[{"content":"One of the very first things you need to use DMR (Digital Mobile Radio) is your DMR id. These are provided by RadioID. Naturally, they require a copy of your licence to prove you hold your call sign, and show a stern warning along with a mock up of an Australian licence saying if it doesn\u0026rsquo;t look like this, you can\u0026rsquo;t proceed.\nUnfortunately, since Australia moved to a class licence system in 2024, I no longer hold a licence with an expiry date etc. I googled around for what to do with no luck, but in the process discovered there was an Australian DMR group on Facebook - \u0026ldquo;VK DMR Network [OFFICIAL]\u0026rdquo; It\u0026rsquo;s a request-to-join type thing, but my application was approved, and about five posts down was someone asking that exact question I had.\nIf you\u0026rsquo;ve come here looking for the answer, it is to find the \u0026ldquo;Letter of Confirmation\u0026rdquo; the ACMA emailed you in 2024 and upload that - it\u0026rsquo;s something only you would have and it includes your name and callsign.\nEven though I never use Facebook these days, I\u0026rsquo;d still recommend joining that group if you\u0026rsquo;re starting in DMR. DMR looks complex to get set up with lots of opportunities to go wrong, and the responses to questions in the group were welcoming and helpful.\n","permalink":"https://vk6mib.com/posts/obtaining-a-dmr-id-with-the-australian-class-licence/","summary":"\u003cp\u003eOne of the very first things you need to use DMR (\u003ca href=\"https://en.wikipedia.org/wiki/Digital_mobile_radio#Amateur_radio_use\"\u003eDigital Mobile Radio\u003c/a\u003e) is your DMR id. These are provided by \u003ca href=\"https://radioid.net/account/register/dmr\"\u003eRadioID\u003c/a\u003e. Naturally, they require a copy of your licence to prove you hold your call sign, and show a stern warning along with a mock up of an Australian licence saying if it doesn\u0026rsquo;t look like this, you can\u0026rsquo;t proceed.\u003c/p\u003e\n\u003cp\u003e\u003cimg loading=\"lazy\" src=\"/images/Screenshot-2026-01-18-at-10.23.18-1024x794.png\"\u003e\u003c/p\u003e\n\u003cp\u003eUnfortunately, since Australia moved to a class licence system in 2024, I no longer hold a licence with an expiry date etc. I googled around for what to do with no luck, but in the process discovered there was an Australian DMR group on Facebook - \u0026ldquo;\u003ca href=\"https://www.facebook.com/groups/691451895982586/\"\u003eVK DMR Network [OFFICIAL]\u003c/a\u003e\u0026rdquo; It\u0026rsquo;s a request-to-join type thing, but my application was approved, and about five posts down was someone asking that exact question I had.\u003c/p\u003e","title":"Obtaining a DMR id with the Australian class licence"},{"content":"I once owned an expensive Kenwood handheld - perhaps a TH-D74 - that I had been excited about because I wanted to try APRS. To get on APRS at the time the option was to buy an expensive radio or to piece together (or home-brew) the audio interface, a GPS and the board to pull that all together.\nRecently, Chinese radios have started to integrate these in reasonably priced handhelds so the last couple of weeks I\u0026rsquo;ve been trying the Vero VR-N76.\nIt\u0026rsquo;s a modern radio in the sense that you can program it over bluetooth as well as using the bluetooth (with it\u0026rsquo;s own app, or a generic app using the built-in KISS terminal) for doing APRS.\nAPRS APRS - Automatic Packet Reporting System - is for sending telemetry packets over amateur radio. Packets can be repeated \u0026lsquo;digi-peated\u0026rsquo; by radios set up for this to form a bit of a mesh. There\u0026rsquo;s no flow control, but packets contain some \u0026lsquo;path\u0026rsquo; information which is altered when they are repeated so they don\u0026rsquo;t live forever and flood the network. Packets can also be \u0026lsquo;iGated\u0026rsquo; onto the internet, which is a useful way to check your packets are getting out.\nThis image is from the very popular aprs.fi that can be used to view packets containing location information.\nHere\u0026rsquo;s a trip from today. I\u0026rsquo;ve hovered over a packet sent from Albany Highway near Boddington. You can see on the map my packet was digipeated by VK6RMS at Mount Saddleback, then again by VK6RAW at Katanning, then iGated to the internet (but not repeated) by VK6SR at the Mount Barker repeater site. Here\u0026rsquo;s the packet that was iGated:\n2026-01-07 18:07:45 AEDT: VK6MIB-9\u0026gt;APN000,VK6RMS-3,VK6RAW-3,WIDE2*,qAO,VK6SR-10:=3255.63S/11644.28Ek305/059/A=000925146.5 / 439.150 A few minutes later my packets were taking a different path:\n2026-01-07 17:06:28 AEDT: VK6MIB-9\u0026gt;APN000,VK6RMS-3,VK6RMW-3,WIDE2*,qAO,VK6ZRW-10:=3306.66S/11656.61Ek321/052/A=001108146.5 / 439.150 Shout out to everyone involved in building and maintaining this infrastructure, - in this case WARG \u0026amp; Southern Electronics Group.\n","permalink":"https://vk6mib.com/posts/back-to-aprs/","summary":"\u003cp\u003eI once owned an expensive Kenwood handheld - perhaps a \u003ca href=\"https://www.universal-radio.com/catalog/ht/3072.html\"\u003eTH-D74\u003c/a\u003e - that I had been excited about because I wanted to try APRS. To get on APRS at the time the option was to buy an expensive radio or to piece together (or home-brew) the audio interface, a GPS and the board to pull that all together.\u003c/p\u003e\n\u003cp\u003eRecently, Chinese radios have started to integrate these in reasonably priced handhelds so the last couple of weeks I\u0026rsquo;ve been trying the \u003ca href=\"https://www.verotelecom.com/VR-N76-Dual-Band-Handheld-Radio-p2511333.html\"\u003eVero VR-N76\u003c/a\u003e.\u003c/p\u003e","title":"Back to APRS"},{"content":"So\u0026hellip; this arrived in my email this morning\nWhat a nice surprise, well done to the organisers. If their plan was to get people thinking about the next contest in July, it\u0026rsquo;s working. I\u0026rsquo;m not a dedicated contester by any means, but the Trans-Tasman was relaxed fun last time, so I\u0026rsquo;m keen to sort out the problems with my dipole and have another shot. I\u0026rsquo;m pretty much a 40m only operator for this due to the difficulty of squeezing in enough wire on the block. I have looked at plans for some loading coils but I\u0026rsquo;m finding it difficult to find the time to get to that and a number of other projects.\nAnother contest I\u0026rsquo;ll have a shot at if I can make the time is the VK Shires. Since I\u0026rsquo;m out in the bush, but in easy 40m range from Perth I should be able to give some points away to the VK6 operators.\n","permalink":"https://vk6mib.com/posts/follow-up/","summary":"\u003cp\u003eSo\u0026hellip; this arrived in my email this morning\u003c/p\u003e\n\u003cp\u003e\u003cimg alt=\"Participation certificate - Trans Tasman\" loading=\"lazy\" src=\"/images/doc.jpg\"\u003e\u003c/p\u003e\n\u003cp\u003eWhat a nice surprise, well done to the organisers. If their plan was to get people thinking about the next contest in July, it\u0026rsquo;s working. I\u0026rsquo;m not a dedicated contester by any means, but the Trans-Tasman was relaxed fun \u003ca href=\"http://vk6mib.com/2015/07/26/trans-tasman-contest/\"\u003elast time\u003c/a\u003e, so I\u0026rsquo;m keen to sort out the problems with my dipole and have another shot. I\u0026rsquo;m pretty much a 40m only operator for this due to the difficulty of squeezing in enough wire on the block. I have looked at plans for some loading coils but I\u0026rsquo;m finding it difficult to find the time to get to that and a number of other projects.\u003c/p\u003e","title":"Follow up"},{"content":"NO84 Using space based digipeaters this weekend I had a couple of firsts. One was successfully having a packet digipeated by PSAT (Parkinson Sat - NO84). This is a 1.5U CubeSat launched in 2015 carrying a APRS transponder and a PS31 experiment.\nI\u0026rsquo;ve heard this satellite before, but yesterday I had a shot at sending it a packet, I heard it digipeated, but didn\u0026rsquo;t receive it back well enough to decode it. I waited 30 seconds or so and had another shot with the same result.\nAlmost immediately I had an email from Brian VK6TGQ with a screen-shot of his DireWolf iGate log showing both packets had been received by him.\nThe PSAT passes have a lot less traffic on them, so I\u0026rsquo;m starting to get interested in trying a QSO. I can see that I could just change the comment in the packets, but there is also a message format in the APRS specification that might work. I\u0026rsquo;ll have to read up on it.\nOn the Go Even though there was an excellent pass of PSAT predicted for 16:40 local, I knew I\u0026rsquo;d miss it as I had to drive back to the farm. I took the D72 just in case, and at the predicted time I heard a couple of bursts on my mobile rig. I swapped the antenna over to the D72 and decoded a beacon packet as I was pulling back onto the road.\nI sent one of mine and heard it digipeated, stopped again to fiddle with the settings (I was transmitting the house symbol instead of the truck) and had another shot. A few minutes later, barrelling along the gravel at about 80 km/h I decoded a packet from Brian.\nShortly after I received a packet from VK6CO-2. Ken runs an iGate at his station, so I was interested to look on findu to see if Brian or I had made the map, but I haven\u0026rsquo;t. Since Brian and VK6CO are not iGating packets from PSAT there must be something about it\u0026rsquo;s path that the iGate software does not like.\nGetting Busy on the ISS The last success for the day was another ISS pass. I tried one this morning but the transponder was still off (they turn it off if they are doing anything tricky - EVA or docking are examples). There was a good pass tonight and I heard packets as soon as it came up over 10º.\nAs usual, it was pretty busy. Here\u0026rsquo;s the packets I successfully decoded:\ncmd:cmd:cmd:UNPROTO was DDA6P1 VIA ARISS,SGATE,WIDE2-1 cmd:cmd:cmd:VK6MIB-6\u0026gt;DDA6P1,RS0ISS*,SGATE,WIDE2-1:\u0026#39;.86l -/\u0026gt;Hi Brian VK6TGQ= VK6TGQ\u0026gt;APDW12,RS0ISS*,PSAT,SGATE,WIDE2-1,OF76TO:!3324.66S/11538.74E`::EMAIL : vk6tgq@gmail.com Hi Brian via Space. VK6PII-7\u0026gt;APK003,RS0ISS*,SGATE,WIDE2-1::VK6CO-2 :gday ken{97 VK6PII-7\u0026gt;D1ELZL,RS0ISS*,SGATE,WIDE2-1:`+Jdl#1S\\\u0026gt;\u0026#34;4F}= VK6HAM-9\u0026gt;SQU4Q9,RS0ISS*,SGATE,WIDE2-1:`,a{l\u0026#34;l\u0026gt;/\u0026#34;7,}Tony via iss VK6CO-2\u0026gt;APRS,RS0ISS*,SGATE:!3154.00S/11556.42E` Igate Perth WA. VK6PII-7\u0026gt;APK003,RS0ISS*,SGATE,WIDE2-1::VK6CO-2 :gday ken{97 VK6PII-7\u0026gt;APK003,RS0ISS*,SGATE,WIDE2-1::VK6HAM-9 :73{98 VK6PII-7\u0026gt;D1ELZL,RS0ISS*,SGATE,WIDE2-1:`+Jdl IS\\\u0026gt;\u0026#34;4D}= VK6TGQ\u0026gt;APDW12,RS0ISS*,PSAT,SGATE,WIDE2-1,OF76TO:!3324.66S/11538.74E`G Day via APRS Satellite from Brian in Gelorup, WA. 73 \u0026amp; Good DX. VK6PII-7\u0026gt;APK003,RS0ISS*,SGATE,WIDE2-1::VK6CO-2 :gday ken{97 VK6PII-7\u0026gt;APK003,RS0ISS*,SGATE,WIDE2-1::VK6HAM-9 :73{98 UNPROTO was DDA6P1 VIA ARISS,SGATE,WIDE2-1 cmd:cmd:cmd:VK6PII-7\u0026gt;D1ELZL,RS0ISS*,SGATE,WIDE2-1:`+Jdl\u0026#34;cS\\\u0026gt;\u0026#34;4E}= UNPROTO was DDA6P1 VIA ARISS,SGATE,WIDE2-1 cmd:cmd:cmd:VK6MIB-6\u0026gt;DDA6P1,RS0ISS*,SGATE,WIDE2-1:\u0026#39;.86l -/\u0026gt;Greetings from Lake Grace= VK5ATN\u0026gt;BEACON,RS0ISS*,SGATE,WIDE2-1:!3408.82S/13824.96E- 73 de Terry - South Australia :-) UNPROTO was DDA6P1 VIA ARISS,SGATE,WIDE2-1 VK5ATN is my current distance record for via the ISS. Here\u0026rsquo;s what was gated (as show on the ariss.net page):\n00:01:22:00 : RS0ISS]CQ,qAR,VK6PII-6:]ARISS - International Space Station 00:01:22:10 : VK6MIB-6]DDA6P1,RS0ISS*,SGATE,WIDE2-1,qAR,VK6PII-6:\u0026#39;.86l -/]Greetings from Lake Grace= 00:01:22:20 : VK6PII-7]D1ELZL,RS0ISS*,SGATE,WIDE2-1,qAR,VK6PII-6:`+Jdl\u0026#34;cS\\]\u0026#34;4E}= 00:01:22:27 : VK6PII-7]APK003,RS0ISS*,SGATE,WIDE2-1,qAR,VK6CO-6::VK6TGQ :73 {99 00:01:22:30 : VK6PII-7]APK003,RS0ISS*,SGATE,WIDE2-1,qAR,VK6CO-6::VK6HAM-9 :73{98 00:01:22:33 : VK6PII-7]APK003,RS0ISS*,SGATE,WIDE2-1,qAR,VK6CO-6::VK6CO-2 :gday ken{97 00:01:22:45 : VK6TGQ]APDW12,RS0ISS*,PSAT,SGATE,WIDE2-1,OF76TO,qAR,VK6PII-6:!3324.66S/11538.74E`G Day via APRS Satellite from Brian in Gelorup, WA. 73 \u0026amp; Good DX. 00:01:22:51 : VK6PII-7]D1ELZL,RS0ISS*,SGATE,WIDE2-1,qAR,VK6CO-6:`+Jdl IS\\]\u0026#34;4D}= 00:01:23:02 : VK6PII-7]APK003,RS0ISS*,SGATE,WIDE2-1,qAR,VK6CO-6::VK6HAM-9 :73{98 00:01:23:05 : VK6PII-7]APK003,RS0ISS*,SGATE,WIDE2-1,qAR,VK6CO-6::VK6CO-2 :gday ken{97 00:01:23:09 : VK6CO-2]APRS,RS0ISS*,SGATE,qAR,VK6CO-6:!3154.00S/11556.42E` Igate Perth WA. 00:01:23:14 : VK6HAM-9]SQU4Q9,RS0ISS*,SGATE,WIDE2-1,qAR,VK6PII-6:`,a{l\u0026#34;l]/\u0026#34;7,}Tony via iss 00:01:23:41 : VK6PII-7]APK003,RS0ISS*,SGATE,WIDE2-1,qAR,VK6PII-6::VK6CO-2 :gday ken{97 00:01:23:47 : VK6MIB-6]DDA6P1,RS0ISS*,SGATE,WIDE2-1,qAR,VK6PII-6:\u0026#39;.86l -/]Hi Brian VK6TGQ= 00:01:24:01 : RS0ISS]CQ,qAR,VK6PII-6:]ARISS - International Space Station 00:01:24:03 : VK6PII-7]D1ELZL,RS0ISS*,SGATE,WIDE2-1,qAR,VK6PII-6:`+Jdl!/S\\]\u0026#34;4E}= I was glad to get gated on this pass, as on my first effort, I had calculated my latitude incorrectly and placed the house icon near Ongerup. Now it\u0026rsquo;s fixed up again.\nI\u0026rsquo;m having a lot of fun with space APRS. The D72 has probably turned out to be the most fun per dollar I\u0026rsquo;ve spent in the hobby.\nI\u0026rsquo;m not sure what the next challenge will be. Perhaps to run the D72 in KISS mode with some APRS client software that can gate packets.\n","permalink":"https://vk6mib.com/posts/more-space-aprs/","summary":"\u003ch3 id=\"psat__2no84\"\u003e\u003cimg alt=\"psat__2\" loading=\"lazy\" src=\"/images/psat__2.jpg\"\u003eNO84\u003c/h3\u003e\n\u003cp\u003eUsing space based digipeaters this weekend I had a couple of firsts. One was successfully having a packet digipeated by PSAT (Parkinson Sat - NO84). This is a 1.5U CubeSat launched in 2015 carrying a APRS transponder and a PS31 experiment.\u003c/p\u003e\n\u003cp\u003eI\u0026rsquo;ve heard this satellite before, but yesterday I had a shot at sending it a packet, I heard it digipeated, but didn\u0026rsquo;t receive it back well enough to decode it. I waited 30 seconds or so and had another shot with the same result.\u003c/p\u003e","title":"More Space APRS"},{"content":"I took my first road trip within range of some earthbound digipeaters and iGates tonight. The D72 was secured on the dash of the ute, but using the dual band whip on the roof. I decoded one packet just out of Narrogin, I assume via VK6-RAW (I haven\u0026rsquo;t read enough of the manual to work out how to sort the list by time yet) but didn\u0026rsquo;t get any of my own packets digipeated back to me until I got much closer to Perth.\nI had the beaconing mode set to Auto, but also sent through some manual packets when I could hear good signals from other packets being repeated. Next on the list is to re-read the manual in much more detail to get my head around all the settings.\nEdited with BlogPad Pro\n","permalink":"https://vk6mib.com/posts/terrestrial-aprs/","summary":"\u003cp\u003eI took my first road trip within range of some earthbound digipeaters and iGates tonight. The D72 was secured on the dash of the ute, but using the dual band whip on the roof. I decoded one packet just out of Narrogin, I assume via VK6-RAW (I haven\u0026rsquo;t read enough of the manual to work out how to sort the list by time yet) but didn\u0026rsquo;t get any of my own packets digipeated back to me until I got much closer to Perth.\u003c/p\u003e","title":"Terrestrial APRS"},{"content":"With a long weekend, and a major project at work behind me, I had a tiny bit of breathing space to play radio this weekend. What I should have been doing is putting in a couple of hours on the AllStarLink for my club (currently at about 30% finished). What prevented this was a new toy scored second-hand from eBay that arrived this week – a Kenwood TH-D72A handheld.\nI grabbed this off eBay, the main attraction being it’s APRS capability, including: built in GPS, stand alone digipeating, and the ability to plug it into a PC and use it as a TNC. My first big plan for this, since I’m miles from anywhere, was to use it to get my staion on the ARISS map by having it digipeated by the International Space Station\nOne of the ISS experiments is Amateur Radio on the International Space Station (ARISS). Most of the astronauts are licensed amateurs - mostly because they occasionally use an amateur radio on board to make scheduled radio contacts with schools for PR reasons. This is a good deal for NASA as they can depend on local amateur radio operators to turn up a school and set up the ground station and help the students run it. It’s a good deal for amateur radio because we get some favourable PR from being associated with such a cool deal.\n[caption id=\u0026ldquo;attachment_480\u0026rdquo; align=\u0026ldquo;alignnone\u0026rdquo; width=\u0026ldquo;720\u0026rdquo;] ISS Russian Service Module showing amateur radio location and VHF antenna[/caption]\nVery occasionally there will be an active amateur on board with some free time and they will make some voice contacts, last year a UK guy was thrilled to make a contact from his garden shed. Sometimes to commemorate an event, they will run SSTV from the radio. The rest of the time, one of the radios is left in “digipeater” mode to repeat APRS packets.\nAPRS (Amateur Packet Reporting System) packets sound just like a half-second’s sequence of musical notes when you hear them on the radio. They can contain all sorts of data to do with what’s going on in your local area – which repeaters are available, which hams are driving around, and even data from weather stations.\nA digipeater takes in an APRS packet of data, inspects it then re-transmits it. The purpose of this is to allow these little packets of information to travel further. Some digipeaters are on tops of towers or mountains, some just at peoples houses.\nThe digipeater on the ISS is obviously a long way up, so it covers a huge area – probably a couple of thousand kilometres across. Getting a packet up all that way can be more challenging than a local repeater; the ISS can be a long way away, and it can be right overhead – a place most antennas have a large null. In addition to these two factors, the pass can be quiet short – usually less than about seven minutes good working.\nI use the website heavens-above.com to work out when I’ll have a good pass. When looking at the data for a pass, the first thing I’m interested in is the altitude in degrees. 90º would be right overhead. I usually don’t get excited about a pass unless it’s going to be above 20º - much lower than that and it’s behind obstacles and deep in the terrestrial noise.\nI had a go at a pass on Saturday – got all set up, watched a live track of the ISS on a website, listened with my squelch open and heard nothing. I knew that Brian VK6TGQ was beaconing from Bunbury, so to hear nothing meant I had a problem with my setup. I carefully looked over everything. Eventually I realised I was on the wrong frequency – 146.850!\nThere was another good pass on Sunday. I could hear other stations’ packets being repeated from just below 20º, but not clear enough for my radio to decode them. As they got clearer I tried a beacon, but still no luck. Then one the way down again at around 45º I heard some really clear packets – my radio didn’t decode them but I thought this was my best chance. I manually beaconed a packet. less than a second later, my radio chirped and updated the display to say my position had been repeated by RS0ISS – the call-sign of the digipeater radio in the Russian module of the International Space Station.\nA few seconds later, Brian saw me on the ARISS map. It’s also possible to extract the raw packet from that site:\n00:00:05:21 : VK6MIB-7]DDF9X2,RS0ISS*,SGATE,WIDE,qAR,VK6PII-6:\u0026rsquo;.80l -/]First try! =\nThis shows that my packet was ‘gated’ by VK6PII (Chris) at his station in Perth. Brian and I are not sure why Brian’s station didn’t also get a clear copy of my packet, he did gate one of Chris’s.\nAnyway, this counts as success, and is probably the shortest purchase-to-successful-use of any of my gear so far. I’m looking forward to getting a handle on everything this radio is capable of.\n","permalink":"https://vk6mib.com/posts/accessing-the-iss-digipeater/","summary":"\u003cp\u003e\u003cimg alt=\"image_product01\" loading=\"lazy\" src=\"/images/image_product01.png\"\u003eWith a long weekend, and a major project at work behind me, I had a tiny bit of breathing space to play radio this weekend. What I should have been doing is putting in a couple of hours on the AllStarLink for my club (currently at about 30% finished). What prevented this was a new toy scored second-hand from eBay that arrived this week – a Kenwood TH-D72A handheld.\u003c/p\u003e\n\u003cp\u003e \u003c/p\u003e\n\u003cp\u003e\u003cimg alt=\"qsl\" loading=\"lazy\" src=\"/images/qsl.jpg\"\u003eI grabbed this off eBay, the main attraction being it’s APRS capability, including: built in GPS, stand alone digipeating, and the ability to plug it into a PC and use it as a TNC. My first big plan for this, since I’m miles from anywhere, was to use it to get my staion on the \u003ca href=\"http://ariss.net/\"\u003eARISS map\u003c/a\u003e by having it digipeated by the International Space Station\u003c/p\u003e","title":"Accessing the ISS Digipeater"},{"content":"The Phillips FM320 UHF CB has the facility to be locked to a particular channel. This is controlled by the existence or absence of a number of diodes on the circuit board. I\u0026rsquo;ve been looking into this for a telecommand project I\u0026rsquo;m working on. I wasn\u0026rsquo;t able to find the information of how to do this anywhere else, but it was pretty straight forward to figure out.\nThis post describes how modify the FM320 radio to set the nominated \u0026ldquo;NOM\u0026rdquo; channel.\nHere is the relevant part of the circuit diagram:\nThe diodes are IN4148. These are commonly available.\nRemove the radio cover. With the controls facing you, remove the bottom left and top right screws (Phillips head). Turn the radio over and repeat. Both covers will now just pull apart to expose the circuit board with the controls and backplate still attached. The location of the diode links is marked below:\nThe table below shows the effect of the diode link being in place. The diodes are listed from left to right as in the above photo and on the circuit diagram. Note that diodes have a specific polarity. Use the other diodes in this photo as a guide for the correct orientation if you are not familiar with them.\nDiode in D34 D35 D36 D37 D40 D41 Channel 10 20 8 1 4 2 Note that these are additive. If you have links in place for D34 \u0026amp; D35 you\u0026rsquo;ll get channel 30. If you need channel 22, then solder in the links for D35 and D41.\nAssembly (as they always said in the Gregory\u0026rsquo;s car manuals of my youth) is the reverse of the disassembly procedure.\n","permalink":"https://vk6mib.com/posts/fm320-nominated-channel-modification/","summary":"\u003cp\u003e\u003cimg alt=\"manual cover\" loading=\"lazy\" src=\"/images/manual-cover.jpg\"\u003eThe Phillips FM320 UHF CB has the facility to be locked to a particular channel. This is controlled by the existence or absence of a number of diodes on the circuit board. I\u0026rsquo;ve been looking into this for a \u003ca href=\"http://vk6mib.com/2016/01/26/phillips-fm320/\"\u003etelecommand project I\u0026rsquo;m working on\u003c/a\u003e. I wasn\u0026rsquo;t able to find the information of how to do this anywhere else, but it was pretty straight forward to figure out.\u003c/p\u003e\n\u003cp\u003eThis post describes how modify the FM320 radio to set the nominated \u0026ldquo;NOM\u0026rdquo; channel.\u003c/p\u003e","title":"FM320 Nominated Channel Modification"},{"content":"\nHere\u0026rsquo;s a blast from my radio past, the Phillips FM320 UHF CB radio. I\u0026rsquo;ve dusted one off from the slowly collapsing box of radios left over from my farming days. My plan is to use one as the receiver for my DTMF pump switch.\nAs a kid I had always been encouraging Dad to consider radios for the farm. I was a regular reader of CB Action and it seemed like the perfect excuse. He never succumbed to this until the advent of UHF CB. We had seen them at one of the field days, and organised for a Phillips representative (a German guy called Hans) to come out to the farm and do a demonstration. Hans arrived with a wind up mast that he set up at the house and wound up to the same height as our TV antenna. Then we drove around the farm to see what the coverage was.\nOur house is about one kilometre away from a large granite rock the top of which is probably 200ft above the TV antenna. Predictably this did cause a black spot. I recall that Hans changed the antenna (to a lower gain one) and reduced the problem area considerably. Dad was sold on it and we purchased four radios - a sizeable investment, but one that paid for itself hundreds of times in time saved by better communications.\nFrom then (this would have been around 1978 - 1980) until about five years ago (advent of better mobile coverage), UHF CB was the standard method of farm communication around the wheatbelt. Each farm used a particular channel and town directories were published with people\u0026rsquo;s UHF channel. Inevitably you shared a channel with someone else and often got an interesting insight into their family relationships. On one memorable occasion we heard one of our neighbours telling his wife off when he could see her turning in the wrong direction whilst bringing his lunch out to the paddock. For the rest of the afternoon his plaintive calls of \u0026ldquo;Are you there Love?\u0026rdquo; went unheeded.\nWe had pretty good experiences with the FM320\u0026rsquo;s. They were used in very harsh conditions particularly with regard to heat and vibration. The only failures I can recall were the numbers on the channel display slowly dying. This didn\u0026rsquo;t bother us much, as 95% of the time we were on \u0026lsquo;our\u0026rsquo; channel. This was facilitated by a switch that allows you to lock to a nominated (NOM) channel. You had to choose the channel when you ordered the radio. We were channel 1.\nWe later added some more FM320\u0026rsquo;s, but I replaced them all with GME TX4000\u0026rsquo;s in the 1990\u0026rsquo;s. The attraction of this upgrade was selcal (selective calling). The GME\u0026rsquo;s could be placed in quiet mode with the squelch locked down until a sequence of tones were transmitted by pressing a button on the microphone. This allowed the radio to remain on at night in the house, without people chatting waking my wife and babies while I was driving the tractor - but still being able to get in contact if I needed something.\nAs part of this project, I\u0026rsquo;d like to change the nominated channel. I think if you don\u0026rsquo;t use the nominated channel the radio powers up on channel 40. The class licence for UHF CB allows for data to be sent on channels 22 and 23 only. I doubt a DTMF tone would annoy anyone, and it\u0026rsquo;s possibly legal anyway (since the selcall tones apparently were) but I like to do the right thing if I can.\nThe circuit diagram (which is in the user manual - ahh, the good old days!) shows a number of dotted diode links near the NOM switch, so doubtless these are the system for setting the nominated channel. Looking around inside the radio this these are the likely suspects.\nLook at those clear markings and that nice big through hole soldering with components you can see without a magnifier. What a pleasure it must have been to fix electronics in the 1980\u0026rsquo;s!\nI can\u0026rsquo;t find a mapping of the diode links to channel numbers anywhere on the Internet. My radio is set to channel 1 and the diode pattern seems to be 0000 10 so it\u0026rsquo;s not as simple as a binary version of the channel number. I\u0026rsquo;ll have to play with shorting some more links out and seeing what happens to try and come up with a scheme. The exact sort of problem I enjoy!\nUpdate: I\u0026rsquo;ve figured it out.\n","permalink":"https://vk6mib.com/posts/phillips-fm320/","summary":"\u003cp\u003e\u003cimg alt=\"Phillips FM320 UHF CB radio\" loading=\"lazy\" src=\"/images/img_6387.jpg\"\u003e\u003c/p\u003e\n\u003cp\u003eHere\u0026rsquo;s a blast from my radio past, the Phillips FM320 UHF CB radio. I\u0026rsquo;ve dusted one off from the slowly collapsing box of radios left over from my farming days. My plan is to use one as the receiver for \u003ca href=\"http://vk6mib.com/2016/01/20/dtmf-tone-control/\"\u003emy DTMF pump switch\u003c/a\u003e.\u003c/p\u003e\n\u003cp\u003eAs a kid I had always been encouraging Dad to consider radios for the farm. I was a regular reader of CB Action and it seemed like the perfect excuse. He never succumbed to this until the advent of UHF CB. We had seen them at one of the field days, and organised for a Phillips representative (a German guy called Hans) to come out to the farm and do a demonstration. Hans arrived with a wind up mast that he set up at the house and wound up to the same height as our TV antenna. Then we drove around the farm to see what the coverage was.\u003c/p\u003e","title":"Phillips FM320"},{"content":"I\u0026rsquo;m in the process of replacing a windmill on the farm with a solar pump. The windmill, carefully adjusted, can keep up with the water consumption at the house and troughs a couple of kilometers away. It isn\u0026rsquo;t perfect; sometimes the house tank overflows and we either water the garden or go down and turn the windmill off for a few days. Sometimes the tank sounds a bit empty and I drive down to the windmill and adjust it for a bit more flow.\nThe solar pump is not so analogue. In order to lift the water the height needed, the centrifugal pump is oversized in relation to the actual flow required. The pump controller can be turned down to some extent, not not enough to avoid overflowing the tank and wasting water. Some system is needed to turn it off an on remotely. My current plan for this is to use DTMF tones over UHF CB radio.\nDual-tone multi-frequency signalling (DTMF) tones are used widely in telephone systems. The frequencies are chosen to be easily transmitted in the narrow voice bandwidths and using two tones for each key allows for a small amount of frequency drift as well as good rejection of noise.\nThe frequencies were originally chosen far enough apart to use analogue bandpass filters for detection, so it\u0026rsquo;s possible that someone smarter than me could implement a simplified Fourier transform that would run on the Arduino. As I need this to be robust, I rejected that idea and decided to use an MT8870 Integrated DTMF Receiver.\nWith a handful of supporting components, this chip will apply filters and digital counting to the incoming analogue signal and output the information as full rail states on five pins. To save money, time, and effort, I purchased a pre-built module for $3.86 on ebay. A particually nice feature of this module is that it has status LED\u0026rsquo;s for each of the output pins - a real bonus when I was debugging my code.\nIt was straightforward to wire up - just the power supply, ground and the five output pins to the Arduino Uno inputs. Arduino users will note I\u0026rsquo;ve changed to the cheap Chinese Arduino clones. At around $5.00 they are great value, but one of the reasons they are so cheap is that they do not use the common FDTI chip for serial comms over USB. Instead they have one of the CH34x chips. These seem to be functionally equivalent, but you\u0026rsquo;ll need to track down and install the driver. I didn\u0026rsquo;t have any drama with this (Mac) but I see many people have been. If you want to avoid all that, just but the genuine ones ($12 if you can wait for them to come from Asia, $35 otherwise).\nMy test setup was a scanner plugged into the module attached to the Arduino, with the Arduino plugged into my USB port, this provided power, serial output for debugging and a source of radio interference! Even without the power supply attached to the laptop, enough RF was getting through to open the squelch on the scanner.\nOne of the outputs of the MT8870 is a pin which goes high when tones are being detected. The test code I\u0026rsquo;ve written scans for this, then when it\u0026rsquo;s detected reads the other pins to determine which code is being received. At the moment, this is just being output as a debug string. When my relay arrives I\u0026rsquo;ll build up the finished hardware and adapt the code to switch it.\n/* ============================================================================== Project: MT8870 DTMF Module test Author: Ian Bailey VK6MIB Created: 19 Jan 2016 Arduino IDE: 1.6.4 Website: vk6mib.com Description: This little module contains the crystal and everything needed to make the MT8870 chip happy. The chip decodes any detected DTMF tones coming in at audio level and sets a binary code on the Q1-Q4 pins. The STQ pin is low when there is no tone and goes high when a valid tone is decoded. The Q pin state is preserved when the tone stops and STQ is grounded. Some credit to: http://arduinobasics.blogspot.com.au/2015/08/mt8870-dtmf-dual-tone-multi-frequency.html ================================================================================= */ //Global variables--------------------------------------------------------------- const int STQ = 3; // Attach DTMF Module STQ Pin to Arduino Digital Pin 3 const int Q4 = 4; // Attach DTMF Module Q4 Pin to Arduino Digital Pin 4 const int Q3 = 5; // Attach DTMF Module Q3 Pin to Arduino Digital Pin 5 const int Q2 = 6; // Attach DTMF Module Q2 Pin to Arduino Digital Pin 6 const int Q1 = 7; // Attach DTMF Module Q1 Pin to Arduino Digital Pin 7 byte BoardState; // current mode/state const byte WAITING = 0; const byte START_OF_TONE = 1; const byte DURING_TONE = 2; const byte END_OF_TONE = 2; byte DTMFread; // The DTMFread variable will be used to interpret the output of the DTMF module. /*=============================================================================== setup() : Prepare the Arduino to receive the MT8700 DTMF module\u0026#39;s output. ============================================================================== */ void setup() { //Setup the INPUT pins on the Arduino pinMode(STQ, INPUT); pinMode(Q4, INPUT); pinMode(Q3, INPUT); pinMode(Q2, INPUT); pinMode(Q1, INPUT); // our starting state is waiting for a tone - note this will ignore the first tone // if it\u0026#39;s being received at boot BoardState = WAITING; // debug code Serial.begin(9600); // set up Serial library at 9600 bps Serial.println(\u0026#34;Hello world!\u0026#34;); } /*=========================================================== loop() : Arduino will interpret the DTMF module output ============================================================ */ void loop() { // use the STQ pin to determine what is happening byte StqState = digitalRead(STQ); if((StqState==HIGH)\u0026amp;\u0026amp;(BoardState==WAITING)){ BoardState = START_OF_TONE; Serial.println(\u0026#34;Start\u0026#34;); DTMFread=0; if(digitalRead(Q1)==HIGH){ DTMFread=DTMFread+1; } if(digitalRead(Q2)==HIGH){ DTMFread=DTMFread+2; } if(digitalRead(Q3)==HIGH){ DTMFread=DTMFread+4; } if(digitalRead(Q4)==HIGH){ DTMFread=DTMFread+8; } Serial.println(DTMFread); BoardState = DURING_TONE; } if((StqState==LOW)\u0026amp;\u0026amp;(BoardState==DURING_TONE)){ // the pin has just gone low at the end of the tone, we can reset the state Serial.println(\u0026#34;End of tone\u0026#34;); BoardState = WAITING; } } ","permalink":"https://vk6mib.com/posts/dtmf-tone-control/","summary":"\u003cp\u003eI\u0026rsquo;m in the process of replacing a windmill on the farm with a solar pump. The windmill, carefully adjusted, can keep up with the water consumption at the house and troughs a couple of kilometers away. It isn\u0026rsquo;t perfect; sometimes the house tank overflows and we either water the garden or go down and turn the windmill off for a few days. Sometimes the tank sounds a bit empty and I drive down to the windmill and adjust it for a bit more flow.\u003c/p\u003e\n\u003cp\u003eThe solar pump is not so analogue. In order to lift the water the height needed, the centrifugal pump is oversized in relation to the actual flow required. The pump controller can be turned down to some extent, not not enough to avoid overflowing the tank and wasting water. Some system is needed to turn it off an on remotely. My current plan for this is to use DTMF tones over UHF CB radio.\u003c/p\u003e\n\u003cp\u003e\u003ca href=\"http://www.beatriceco.com/bti/porticus/bell/telephones-technical_dials-touchtone.html\"\u003e\u003cimg alt=\"DTFM Keypad layout.\" loading=\"lazy\" src=\"/images/dtmf.gif\"\u003e\u003c/a\u003eDual-tone multi-frequency signalling (DTMF) tones are used widely in telephone systems. The frequencies are chosen to be easily transmitted in the narrow voice bandwidths and using two tones  for each key allows for a small amount of frequency drift as well as good rejection of noise.\u003c/p\u003e\n\u003cp\u003eThe frequencies were originally chosen far enough apart to use analogue bandpass filters for detection, so it\u0026rsquo;s possible that \u003ca href=\"https://github.com/jacobrosenthal/Goertzel\"\u003esomeone smarter than me\u003c/a\u003e could implement a simplified Fourier transform that would run on the Arduino. As I need this to be robust, I rejected that idea and decided to use an MT8870 Integrated DTMF Receiver.\u003c/p\u003e","title":"DTMF Tone Control"},{"content":"I\u0026rsquo;m always fascinated with the operating kits people take portable. There are a heap of interesting trade-offs to make. Here\u0026rsquo;s my usual HF kit:\nFT-857ND MFJ 904H Travel Tuner 20m braided wire (with teflony stuff in it) 4S 4.2AhLiFePo 7m Squid Pole and a couple of straps This all fits in one of those insulated wine picnic bags (I tossed the plastic wine glasses and corkscrew). I have a cheap laptop case I put the radio in first so it doesn\u0026rsquo;t get scratched by the other gear. The tuner zips into the glasses pocket.\nI run the antenna as a sloper from the squid pole if there\u0026rsquo;s no tree. I generally only run 20m portable. If I have the time to operate it\u0026rsquo;s usually in the middle of the afternoon and 20m is open to somewhere. Given this situation I could possibly lose the tuner and make a dipole. Doing this and comparing it will be a project for the future.\nThe change to a LiFePo from a gel cell is a recent one. If I\u0026rsquo;m in a vehicle I\u0026rsquo;ll usually take a gel cel that I salvaged from a dead UPS. I generally only operate for a couple of hours and most of that listening; either battery easily does that. The LiFePo is a fraction of the weight of the other. The small meter you can see in the photo plugs into the balance taps on the battery and alerts me if the power is too low. I\u0026rsquo;m very fond of this battery, I\u0026rsquo;ll often use it at home if I feel like operating from the coffee table and can\u0026rsquo;t be bothered moving my power supply and finding an extension cord.\nI recently travelled down to Albany in a rented bus on a job where I needed the ability to monitor UHF CB. The Southern Electronics Group has recently done some work on the Mount Barker repeaters so I thought I might get a chance to range test them a bit as well (sadly this did not pan out). The FT-857ND was an overkill for that so I took a Wouxun KG-UV950P, gel cell, and Nagoya 77-BH on a mag mount.\nThe funky radials on the antenna are a recent eBay impulse purchase - the theory is it will capacitively ground to the vehicle better. I haven\u0026rsquo;t made any careful attempt to compare the with and without situation yet. That\u0026rsquo;s yet another project for the future.\nIf I\u0026rsquo;m staying anywhere for a few days I generally take this Wouxun KG-UV950P and a WARG 2m coaxial dipole (they sell them as the Pogo Stick). I have a 920P in my ute, but the 950 is better for this purpose as I sometimes listen to the aero-band.\n","permalink":"https://vk6mib.com/posts/portable-kit/","summary":"\u003cp\u003eI\u0026rsquo;m always fascinated with the operating kits people take portable. There are a heap of interesting trade-offs to make. Here\u0026rsquo;s my usual HF kit:\u003c/p\u003e\n\u003cp\u003e\u003cimg alt=\"pvnzz8z\" loading=\"lazy\" src=\"/images/pvnzz8z.jpg\"\u003e\u003c/p\u003e","title":"Portable Kit"},{"content":"Common advice to new Amateur radio operators asking questions about antennas is that “anything is better than nothing”. The idea being that you can always improve things later, but for now do something to get on the air.\nI live in a small rental unit in a rural town, with overhead power lines across the front of my block. As far as antenna’s go, the only thing in my favour is that many houses nearby have UHF CB colinears mounted on roofs or free standing at around 6-7m. This proliferation of CB antennas is not a symptom of a thriving CB culture – more that mum and dad usually retire into town when sons take over the day to day operation of farms, and that before the widespread use of phones UHF CB was a staple of farm communications.\nLike many hams, I’m slightly snobbish about making my own wire antennas, however when I ordered my first radio I shelled out for a half-size G5RV made by MFJ – the MFJ1778M. My thinking was that I wanted to be on the air the day the boxes arrived – which I assumed would be sometime that same week. That order ended being a drawn out process (over two months) so in fact I had plenty of time to make a dipole.\nWith the space restrictions I’ve got, and the background noise (usually S7-8 on 40m) I don’t expect wonders from any antenna I have up here, but the limited time I have for the hobby means that if I can only operate portable it won’t happen much.\nThe G5RV ‘Jnr’ is basically a 30m dipole fed with 10m of 450 ohm ladder line. In the proper G5RV configuration it’s meant to be fed with a good length of coax connected directly to the ladder line. Part of the magic of the G5RV is that the length is chosen so it does not present an outrageous impedance at any of the main HF ham bands, so that with a tuner multi-band operation is possible. With the half-size version I’ve got, this should be 10-40m.\nThe other part of the magic of a G5RV is the specific length of ladder line and the lump of coax on the end of this. I don’t follow the theory here, and it seems to be controversial whenever it’s discussed on the internet. Another reason for my scepticism is the trouble I had with fluctuating SWR from mine until I installed a 1:1 balun between the ladder line and coax.\nDipoles should be installed at a height of at least half the wave length of operation. Since I want to work 40m with mine, it should be up at 20m. Since mine is at 6m I’m not expecting nice horizontal lobes. In fact in my current configuration I am basically operating NVIS (signals are being radiated mostly straight up and will bounce down in a cone around my location) which suits me fine – what I’d like to do is to be able to reliably make contacts around the southern half of WA.\nI purchased a 6m aluminium tube for the support for one end. This has a stainless link attached with a hose clamp. I use some parracord through this to raise and lower the antenna if I need to do any maintenance. For the support at the other end I have a similar arrangement terminated on the top of my TV antenna support. I thought the tension might bend the TV stick but it does not seem to have yet. Luckily one of the support braces is exactly in line with the antenna.\nYou can see from the photos that it all looks a bit temporary. I really want the ladder line all perpendicular to the dipole, but as it’s so low this would mean it would be sitting on the ground. To avoid this, when it’s deployed it is pulled out to sit on one of my outdoor chairs. When I’m not operating, I just hook the balun up on a handy veranda post so it’s out of the way of the lawnmower man.\nThe other dodgy looking effort is the way I’ve attached the aluminium poll to the fence. I originally used the G clamps to hold it, thinking that the next weekend I’d fabricate a bracket that would slide down over it and the fence. After a few months this seemed less and less important and disappeared off my list of things to do.\nWith this arrangement I’ve made solid contacts as far away as Tasmania on 20m and 40m. My main gripe is not having 80m. I can receive just fine, and can tune it up but the signal that gets out to Perth is tiny – not good enough for a rag chew. My plan for this is to try shorting the bottom of the twinlead and using it as a vertical with some counterpoise. I’ll do that one day… before I replace the G-clamps!\n","permalink":"https://vk6mib.com/posts/getting-it-up/","summary":"\u003cp\u003e\u003cimg alt=\"View of a backyard with a dipole antenna. Feedline can be seen coming down at a 30º angle\" loading=\"lazy\" src=\"/images/img_5983-copy.jpg\"\u003eCommon advice to new Amateur radio operators asking questions about antennas is that “anything is better than nothing”. The idea being that you can always improve things later, but for now do something to get on the air.\u003c/p\u003e\n\u003cp\u003eI live in a small rental unit in a rural town, with overhead power lines across the front of my block. As far as antenna’s go, the only thing in my favour is that many houses nearby have UHF CB colinears mounted on roofs or free standing at around 6-7m. This proliferation of CB antennas is not a symptom of a thriving CB culture – more that mum and dad usually retire into town when sons take over the day to day operation of farms, and that before the widespread use of phones UHF CB was a staple of farm communications.\u003c/p\u003e","title":"Getting it up"},{"content":"I’m a member of a fairly active group – the Bunbury Radio Club. The club’s history stretches back to the 1970’s boom in CB radio and we are open to all radio enthusiasts, not just amateur radio operators - although almost all current members are licensed. As the club has experienced some growth in the last couple of years, we are increasingly conscious of the need to project a positive image for the club and amateur radio in general.\nOur ‘uniform’ is a black polo shirt with the club badge sewn on. Two of these badges are given to each member as they first join and I\u0026rsquo;m proud to be seen sporting mine.\nAn idea we’ve had lately is to purchase some hi-vis vests and have them printed with the logo and the words ‘Amateur Radio’. The point of this is to keep our members safe when they are working around roads (fox hunts etc) or worksites (repeater repairs), or just public events where we can promote the club and hobby.\nTo order the vests, I needed an electronic version of the logo. Fellow club member Brian VK6TGQ had already been through the process of digitising the logo from a scan of the badge, and kindly forwarded me a number of jpeg versions and his original Viso file for this. I used Viso extensively in another life years ago, but don’t have access at home or work to this software. Since I’ve been meaning to investigate the vector graphics program Inkscape for ages, this seemed like the ideal opportunity.\nMany graphics programs, including the ones non-experts are likely to have encountered such as Paint, are bitmap based. That is to say the image is made up of individual pixels set to particular colours. This makes a lot of sense as this is how images are displayed on screens, however it has a downside that you are probably familiar with - when you zoom in on a bitmap based image, at some stage the individual pixels become obvious.\nIn a vector based image, the picture elements are described as being curves anchored at particular points. When you zoom in on a vector based image, it just gets bigger, not blocky. You could try that now on this web page (mac – command+, windows – control+) - the fonts are vectors so they grow and retain their shapes.\nThis sort of project (working out something in some new software you haven’t tried before) frequently becomes one of those jobs that turns out to be harder, and takes longer, than you thought. Not so for this exercise. It took about 45 minutes from opening the program to exporting the final design and was actually fun! I’m highly recommending Inkscape if you have this type of task to complete.\nThe starting point was to pull in a scan of the badge and draw the circles. As expected, the badge was not perfectly circular. To cause the two circles to be concentric, I used the Object|Duplicate command to copy the first, then resized it with the Control key held down to retain the centre during resizing.\nFor the electron orbits, I drew an ellipse and resized, moved, and rotated it until it was a reasonable match with one from a badge. Rotating took me a minute to work out. When you select an object in Inkscape the resize handles appear around it, to get the rotate handles you need to click on it again.\nIn the process of doing this, I had moved the ellipse around so that it was no longer neatly aligned with the circles. Luckily, the Objects menu has an align tool, and it made short work of lining the vertical and horizontal middle of the eclipse up with the circles. To create the second and third orbits I used the duplicate tool again the rotated them by 60° and 120°. In Brian\u0026rsquo;s version of the logo he had cut the electron orbits where they crossed over each other to give them more of a 3D feeling. I decided to ignore this nicety.\nThe actual electrons were just drawn as a small circle then copied and moved to ensure they matched one another.\nI was expecting the text to be the hardest part, but it was also pretty straightforward. In Inkscape, most shapes are \u0026lsquo;paths\u0026rsquo;. Once a path has been drawn, text can be attached to it and will flow along it. To do this, you create a path, (I used another concentric circle) and the text, then just use the Object |Text to Path tool. When I did this, the text was flowing around the wrong way, flipping it horizontally and changing the diameter of the circle fixed that. I had to create a different circle for the \u0026ldquo;W.A.\u0026rdquo; Text at the bottom.\nThe two diamonds on the bottom were just rectangles resized and rotated, and I was done!\n","permalink":"https://vk6mib.com/posts/inkscapades/","summary":"\u003cp\u003e\u003cimg alt=\"Bunbury Radio Club Badge\" loading=\"lazy\" src=\"/images/image_1_hires.jpg\"\u003eI’m a member of a fairly active group – the Bunbury Radio Club. The club’s history stretches back to the 1970’s boom in CB radio and we are open to all radio enthusiasts, not just amateur radio operators - although almost all current members are licensed. As the club has experienced some growth in the last couple of years, we are increasingly conscious of the need to project a positive image for the club and amateur radio in general.\u003c/p\u003e","title":"Inkscapades"},{"content":"I’ve been meaning to write a follow up to my earlier post about the Feature Tech antenna analyser. The short summary of that post was that when I hooked up the antenna analyser to a mobile whip on a magnetic base, I saw all sorts of SWR values which were often not repeatable and changed even as I was taking my hand away from the meter. I was disappointed with the device.\nFast forward a few weeks, in a QSO with Martin VK6ZMS and he was strongly of the opinion that I was doing myself a disservice by running a mag mount without grounding the antenna to my vehicle close to the base of the antenna. Another clue was one idle afternoon at home, I threw the analyser on my WARG Pogo Stick 2m antenna and it had none of the problems I had seen. The SWR readings were reliable (you could read of a value for a frequency, change the frequency then change it back and get the same SWR value) and did not alter as I handled the coax or moved away from the meter. One of the features of this antenna is that it has an coax choke at the base.\nThese two events made me suspect that the problems I’d seen with the analyser may in fact have been related to poor antenna installation letting RF back down the coax, which then interacted capacitively with the surroundings including me.\nI’m working away from my normal home at the moment, and will be moving out in a week or so. I thought I might take down my new Diamond X-50 this weekend as part of the packing up I’ve started on. Since it’s reasonably well installed up away from the roof and in the clear, I thought I might run the antenna analyser across it and make some charts.\nThere is a bit of a tricky compromise when buying Diamond 2m/70cm antennas. Andrews Communications (where I purchased this one and had a great shopping experience) explain it this way:\nWe import, sell and recommend JA-version multiband Diamond vertical antennas. Those models covering the 2m and 70cm bands (or more) are centred on 145MHz and 435MHz and will cover 144-148MHz and 430-440MHz. The swr at 148MHz is 1.8:1 to 2:1 and we know of no problems ever encountered due to this swr present at the top of 2m. This version has been conclusively proven over the past 35+ years to be best suited to the Australian and New Zealand 2m/70cm band plans. Alternatively, we can import \u0026ldquo;A\u0026rdquo; suffix (USA) version multiband verticals. However, they would be at higher pricing and their delivery timing would require confirmation. They are centred on 146Mhz and 443MHz (i.e. 8MHz higher on 70cm), covering 144-148MHz and 437-450MHz. Diamond V/U multiband base station verticals tuned specifically for Australia/NZ band plans simply do not exist!\nI guess the most common use for these sorts of antennas is going to be FM repeaters and simplex, so looking at the new WIA bandplan, the 2m FM is from 144.7 MHz to 148.0 MHz (centred on 146.35 MHz) and 70cm 431.0 MHz to 440.0 MHz (centred on 435.5 MHz). The X-50 is the second smallest of the range, so I imagined that it was not as bigger deal in the lower gain antennas (4.5dB and 7.2dB) and took Andrews’ advice.\nIf the analyser can be trusted, the X-50 in the current mounting situation looks fine in the critical frequencies. In a perfect world it would be mounted on a longer pole to get it further away from the roof and TV antenna, and it would have a more direct run of lower loss coax, but even so I’m happy with how it measures up.\nWhile I was collecting data, I had a look outside the amateur spectrum, just because I like measuring things. I must say I don’t really understand the reason for the cyclical nature of the SWR as the frequency changes. It would make sense at the various multiples and integer fractions of the resonant frequency, but there seems to be a lot more of them than that. A job for another day might be to repeat this exercise on a simpler antenna and look at the lumps to see if I can workout what the cause of each one is.\n","permalink":"https://vk6mib.com/posts/diamond-in-the-sky/","summary":"\u003cp\u003e\u003cimg alt=\"AW07A\" loading=\"lazy\" src=\"/images/aw07a.jpg\"\u003eI’ve been meaning to write a follow up to my earlier \u003ca href=\"/aw07a-antenna-analyser/\"\u003epost about the Feature Tech antenna analyser\u003c/a\u003e. The short summary of that post was that when I hooked up the antenna analyser to a mobile whip on a magnetic base, I saw all sorts of SWR values which were often not repeatable and changed even as I was taking my hand away from the meter. I was disappointed with the device.\u003c/p\u003e\n\u003cp\u003eFast forward a few weeks, in a QSO with Martin VK6ZMS and he was strongly of the opinion that I was doing myself a disservice by running a mag mount without grounding the antenna to my vehicle close to the base of the antenna. Another clue was one idle afternoon at home, I threw the analyser on my WARG Pogo Stick 2m antenna and it had none of the problems I had seen. The SWR readings were reliable (you could read of a value for a frequency, change the frequency then change it back and get the same SWR value) and did not alter as I handled the coax or moved away from the meter. One of the features of this antenna is that it has an coax choke at the base.\u003c/p\u003e","title":"Diamond in the Sky"},{"content":"Yesterday on the way back from a BRC meeting, I stopped in at Harvey to try and track down some interference we are getting on the 70cm repeater VK6RBY that is located on the scarp just east of the town. Listening on the input frequency 433.650 MHz the squelch was breaking as I entered the town limits. Within a few minutes of driving I’d tracked it down to a particular town block.\nI hopped out of my ute and tried to use the scanner to try and narrow it down further – without much luck. I’ll have to come back with a yagi to do any better. Since there seems to be a constant carrier with the occasional burst of pulsing, it’s probably a telemetry device of some sort.\nInterference to UHF amateur radio repeaters is a common issue, as the input frequencies in many countries overlap with the LIPD (low interference potential devices) band. In Australia LIPD devices are covered by a class licence that allows 433.05–434.79 MHz to be used with up to 25mW. Gadgets such as garage door openers and short range video senders are the types of transmitters in common use.\n25mW is not much power, but standing on the side-walk near the source of the signal I could see the repeater tower, so it’s possible this is a legal device. However, plenty of higher powered devices, including telemetry transmitters can be found on eBay capable of transmitting between 100mW and 1400mW.\nAs I was walking around with the scanner, I realised I hadn’t locked my ute, I pressed the lock button on the key fob and heard a chirp through the radio – clearly my Mazda key fob is a 433 MHz device. The chirp sounded like it might be some frequency shift keying (FSK), so I was keen to have a look at its spectrum. That seemed like a good job for my RTS-SDR dongle.\nThese little devices look like a USB thumb drive and can be had for about $10 on eBay.\nThey are intended for watching digital TV on your laptop. Based on the RTL2832U and R820T chips, they are actually wide band VHF-UHF receivers.\nSome smart hacker realised that the IQ output could be captured and processed and now there is open source software for most platforms so they can be used for radio fun. They are not high quality, and the output ends up with a few birdies and images, but if you want to take a quick look at a signal they are very handy.\nHere is a screenshot of the software I use on the Mac – GQRX while the key fob is transmitting.The top part of the display is a Fast Fourier Transform (FFT) of the signal – basically a graph where the x axis is frequency and the y axis is the amplitude of the signal. The signal we are interested in is the two spikes in the centre. It clearly is FSK using two tones about 100 KHz apart. The bottom part of the screen is a waterfall display and you can just see the signal emerging.\nHere’s a short video so you can see it in action.\nhttps://www.youtube.com/watch?v=n-PgSDw3xY8\nI can’t see how to speed up the waterfall (to effectively stretch it out), if I could do that, we’d see the individual bits of the data being sent. Another approach would be to record the output as a WAV file (GQRX allows this) and process it to extract the timing of the high and low tones.\nIt would be possible to then transmit the code with an amateur UHF radio, but even if I had correctly decoded, and re-encoded the data this would be unlikely to unlock the car. These systems usually use some sort of rolling code (the code is different each time) to prevent this exact type of attack. In the rolling code system the receiver knows the next few codes the transmitter might send using an algorithm. Successful rolling code attacks generally rely on capturing a code at the same time as preventing its reception by the intended receiver - not a simple process if they are in range of each other.\nIf you haven’t got one of these RTS dongles, I highly recommend you grab one and have a play. It was nice to have it lying around when I needed it for this job, and you can\u0026rsquo;t beat the price.\n","permalink":"https://vk6mib.com/posts/rts-sdr-sleuthing/","summary":"\u003cp\u003e\u003ca href=\"https://commons.wikimedia.org/wiki/File:Harvey_SW_Highway.jpg\"\u003e\u003cimg alt=\"Harvey_SW_Highway\" loading=\"lazy\" src=\"/images/harvey_sw_highway.jpg\"\u003e\u003c/a\u003eYesterday on the way back from a BRC meeting, I stopped in at Harvey to try and track down some interference we are getting on the 70cm repeater VK6RBY that is located on the scarp just east of the town. Listening on the input frequency 433.650 MHz the squelch was breaking as I entered the town limits. Within a few minutes of driving I’d tracked it down to a particular town block.\u003c/p\u003e\n\u003cp\u003eI hopped out of my ute and tried to use the scanner to try and narrow it down further – without much luck. I’ll have to come back with a yagi to do any better. Since there seems to be a constant carrier with the occasional burst of pulsing, it’s probably a telemetry device of some sort.\u003c/p\u003e","title":"RTS-SDR Sleuthing"},{"content":"I’ve been drawn away from time playing with radio for a couple of months, working away in another town to backfill someone else’s (harder) job. In addition to the time involved in getting my head around the new job, it means starting from scratch again with antennas etc, and I haven’t brought all my gear so whenever I do have an hour to play, I’ve often not got the tools or equipment I’d like. As a result I’ve been keeping in touch by catching up on a number of podcasts and I thought it might be interesting to talk about a couple of them plus some other ham news sources.\nI’ve brought the FT-857D with me and got that set up in a spare room with the intention of getting on 2m. I was so impressed with the coverage of VK6RAV when I was up in the northern wheat belt, I thought I might get into that here, about 100 east of Perth.\nI had the WARG pogostick up on the TV antenna post for a couple of weeks, and swapped it yesterday for a Diamond X-50 dual bander. With both of these, and my legal 30W I can trigger VK6RAV but it’s far to scratchy to use. The Diamond is noticeably better, but not enough to make it usable. I’m about the same distance to the main Perth repeaters at Roleystone (VK6RAP \u0026amp; VK6RLM) and can’t key either of them up, which just goes to show what a great job the WARG guys have done with VK6RAV.\nEven though it hasn’t brought me much joy, I’ve left the X-50 up there and currently have the FT-857D scanning through the 2m and 70cm simplex call channels as well as the local railway comms repeater. The train tracks are about 200m from my bedroom window and the level crossing in the middle of town is not much further. It’s sort of fun to hear the locomotive drivers getting instructions to pull into the loop to let another train through on the radio then hearing the rattle as they back out past the points and into the loop.\nApart from that, my radio time at the moment is mostly just listening to podcasts and news on headphones while I’m catching up on housework.\nICQ Podcast\nThis podcast is a long running one with very regular updates and is put together by father and son team Martin and Colin Butler from the UK. Colin is a newish amateur but Martin is an old hand and a PMR radio technician so they have a great breadth of experience. Additionally Martin is an instructor so he has a natural tendency to explain things well.\nThey have a fair bit of personality in their podcast, so that might suit you or not, I find it quite nice, especially the earlier episodes where they do the podcast together. They cover all sorts of topics related to radio, including a feature in each episode. As well as trawling through the news, they also comment on it, which often leads to interesting comments.\nSolder Smoke\nSolder Smoke is produced by American Bill Meara and currently co-hosted by Pete Juliano. As you can probably guess from the name it has a home-brew flavour with many interesting discussions about the travails the hosts encounter in their shacks as they design and build radios and radio related equipment. I’m not a big home brewer – too time consuming for me at the moment – but I am getting a better technical understanding of things from listening to this. Bill is a very personable fellow and has had an interesting past.\nMy other good source of what’s happening, particularly more locally, are the WIA weekly broadcast and the Newswest Broadcast.\nThe Wireless Institute of Australia (WIA) is the national body representing Australian Amateurs. They produce a weekly broadcast that covers the activities of the WIA as well as news of general interest to radio enthusiasts. It’s broadcast on Sundays on a number of frequencies including the main 2m repeater in Perth. Once I’ve got an 80m receiving setup I’ll probably listen to it that way, but for the moment I’m stuck downloading it from the WIA website.\nA new ‘club’ in WA is Newswest. This group of amateurs provide a great service to local amateurs by producing a local ham radio news (as well as some other great stuff). All the re-broadcasters of the main WIA news in WA transmit the Newswest version directly after it. Although it’s quite professionally produced, it has a lovely local vibe with stories from the WA clubs and personalities.\nSo keeping in touch is easy and enjoyable, but I’m hankering to get back to playing!\n","permalink":"https://vk6mib.com/posts/the-download/","summary":"\u003cp\u003eI’ve been drawn away from time playing with radio for a couple of months, working away in another town to backfill someone else’s (harder) job. In addition to the time involved in getting my head around the new job, it means starting from scratch again with antennas etc, and I haven’t brought all my gear so whenever I do have an hour to play, I’ve often not got the tools or equipment I’d like. As a result I’ve been keeping in touch by catching up on a number of podcasts and I thought it might be interesting to talk about a couple of them plus some other ham news sources.\u003c/p\u003e","title":"The Download"},{"content":"The enterprising ex-secretary of my club, Brian VK6TGQ coordinates an “experimenters net” most Sunday mornings in Bunbury wherein different aspects of Amateur radio are played with. Over the last month or so they have been experimenting with sending Slow Scan TV over 2m simplex. From this distance I have not been involved in this apart from occasionally joining them on the IRC channel to see what they are up to.\nThe equipment to do this can be pretty basic. They started out just with an app on their phones, to transmit, the app loads the image and plays a series of tones (FSK) as each line of the image is transmitted. If you don’t have a cable into your transmitter, you key the transmitter and hold the phone speaker up to the mic. A similar arrangement is possible for receive – the phone is left near the transceiver speaker and converts the tones (and any nearby noises) back into an image. Crude, but results are possible. A much improved result can be obtained by connecting the transceiver to the decoding device (usually a computer tablet or smartphone).\nLast Friday Brian advised that the International Space Station (ISS) was planning to transmit SSTV to commemorate 40 years of space cooperation between the USSR and the USA that started with a Soyuz docking with one of the last Apollo missions. It’s not well know outside of radio circles that almost all astronauts and cosmonauts are licensed amateur radio operators and that they occasionally operate the ISS ham radio station, especially with groups of school children.\nWe used the satellite prediction service on the Heavens Above website to look at the available passes. Based on my experience of SO50 I was discounting some of the lower passes. This changed when Steve VK6HSB reported that he had heard a good carrier (but no modulation) on one of the low Friday night passes. When I tuned in on Saturday afternoon for a pass, using my WARG unity gain pogo stick for an antenna, I too heard a full quieting carrier for about 3 minutes – all that would be needed to receive an image.\nFor decoding the images, I have an old Nexus 7 Android tablet I purchased off ebay. A lot of ham radio software runs on Android (to a much greater extent than iOS). However I made a mistake with this purchase. I wasn’t aware that it does not have a ‘mic in’ in the headphone plug, so I was restricted to using the tablet-sitting-on-the-speaker method. The ISS was transmitting in the PD180 format, and I used a free app called \u0026lsquo;Robot-36\u0026rsquo;.\nSaturday lunchtime I had some success. Here is the image I received.\nThe green dots are caused by noise. Some of it over the radio, but some just environmental noise in my unit. This was still a low-ish pass. Another was scheduled for about an hour later.\nI was better prepared for the next pass. I used HamSat on the iPad to show the location of the ISS as well as to calculate the changes to the receiving frequency required to adjust for the Doppler.\nIn the next pass a couple of much better (but still far from perfect) images were captured.\nIn this same pass, Brian captured a near perfect image using a cable.\nOn Sunday we discussed the operation – working together on these sort of projects is a great way to maintain the enthusiasm by getting helpful advice from each other to make success more likely, as well as getting encouragement for your efforts when things don’t work perfectly.\nIt’s possible to do SSTV on HF, so I think I’ll acquire or make a basic cable and investigate Mac software for the mode.\n","permalink":"https://vk6mib.com/posts/sstv/","summary":"\u003cp\u003eThe enterprising ex-secretary of my club, Brian VK6TGQ coordinates an “experimenters net” most Sunday mornings in Bunbury wherein different aspects of Amateur radio are played with. Over the last month or so they have been experimenting with sending \u003ca href=\"https://en.wikipedia.org/wiki/Slow-scan_television\"\u003eSlow Scan TV\u003c/a\u003e over 2m simplex. From this distance I have not been involved in this apart from occasionally joining them on the IRC channel to see what they are up to.\u003c/p\u003e\n\u003cp\u003eThe equipment to do this can be pretty basic. They started out just with an app on their phones, to transmit, the app loads the image and plays a series of tones (FSK) as each line of the image is transmitted. If you don’t have a cable into your transmitter, you key the transmitter and hold the phone speaker up to the mic. A similar arrangement is possible for receive – the phone is left near the transceiver speaker and converts the tones (and any nearby noises) back into an image. Crude, but results are possible. A much improved result can be obtained by connecting the transceiver to the decoding device (usually a computer tablet or smartphone).\u003c/p\u003e","title":"SSTV"},{"content":"Now my dipole is up semi-permanently, I can sort of operate every weekend I’m home. I say ‘sort of’ as it’s much noisier here in town than at the lookout where I made my first contacts, and I suspect I don’t get out as well with this little half size G5RV at only 6m high.\nI turned the radio on last Saturday afternoon to have a tune around and heard VK6QM calling CQ contest. I wasn’t aware there was a contest on, but when no one else was answering I called back and got a quick lesson in what the exchange was (signal report and contact serial number) and scrawled that and my times on a piece of paper.\nAfter looking up the rules on the WIA web site, I was keen to get back into it – a good opportunity to get some signal reports and a feel for where I was getting out too. The Trans-Tasman is a low-bands contest 40/80/160m. My 160m here is non-existent and 80m very marginal but I thought I’d be able to give some points away on 40m while it was still open.\nThe rules allow for repeat contacts in each of the three two hour periods. I decided that I’d need a better system for keeping track of things than my current logging software (HamLog) and downloaded the VK Contest Logger (VKCL3). This software is designed for Australian contests and it handles all the complexity of the rules for you.\nFor example, during this contest I was tuning up and down (the search \u0026amp; pounce method). If I heard someone calling CQ I could just type their call into VKCL3 and it would let me know if I’d contacted them on this band in this time slot. If it indicated that this call sign was worth points, I could go ahead and make the contact and just type the call and serial number into VKCL3 to log the contact. The software also keeps track of what my serial number for each contact was.\nI wasn’t contesting very seriously as I had other work to do, and after sunset most of the action moved to the lower bands but it was still fun to make these short contacts and support the VK6 community by giving away some points.\nI finished my contesting night with an 80M contact with VK6QM, nicely bookending my first foray into contests. I finished with 18 points (a tiny total compared to others). Although I stuffed up the serial number for one of the contacts. I left him in the log as perhaps he’ll get the point when the contest manager matches the logs. Speaking of logs, it was a simple matter to export it from VKCL3 for upload. The log contains all the time, band, call sign and exchanges for each contact. I imagine they are validated against each other somehow – hence the importance of submitting my log even though I wasn’t competitive.\nI’m definitely keen for more of this. If you haven’t had a go at a contest, I’d recommend it, and I highly recommend the VK Contest Logger software if you are going to give a local contest a try.\n","permalink":"https://vk6mib.com/posts/trans-tasman-contest/","summary":"\u003cp\u003e\u003cimg alt=\"G5RV Jnr\" loading=\"lazy\" src=\"/images/antenna.jpg\"\u003eNow my dipole is up semi-permanently, I can sort of operate every weekend I’m home. I say ‘sort of’ as it’s much noisier here in town than at the lookout where I made my first contacts, and I suspect I don’t get out as well with this little half size G5RV at only 6m high.\u003c/p\u003e\n\u003cp\u003eI turned the radio on last Saturday afternoon to have a tune around and heard VK6QM calling CQ contest. I wasn’t aware there was a contest on, but when no one else was answering I called back and got a quick lesson in what the exchange was (signal report and contact serial number) and scrawled that and my times on a piece of paper.\u003c/p\u003e","title":"Trans-Tasman Contest"},{"content":"I went out for my first shot of HF operating today had had some success as well as learning a couple of lessons.\nThe set up was at a local lookout - it has a slight elevation compared to town, it\u0026rsquo;s out of the noise (nearest power-line is about 400m away) and partially surrounded by the salt lake that the town is named for. The lookout has an iron railing that is perfect for strapping my 7m squid pole to. The plan was to hook 20m of wire from that down to the back of the ute and run it as an end-fed.\nLesson 1 - there is only so much tension that can be placed on a squid pole before it snaps.\nSo, I ended up with a six metre pole but the east/west antenna at the east end was probably seven or eight meters up from ground level then sloped down to my ute where I had set up. As my 40m dipole at home tunes up on a couple of bands, I was hoping this arrangement might be multi-band as well, but no luck there.\nLesson 2 - 20m end-fed antennas are good on 20m.\nIn any case as soon as I tuned up on 20m it was clear this was a whole lot better from a noise point of view than at my house. I don\u0026rsquo;t want to say the noise was S1 - because I don\u0026rsquo;t quite understand the interaction of my S meter and the RF gain control, but it was substantially quieter. Tuning around the band I found plenty going on - several eastern states VK\u0026rsquo;s rag chewing and some DX from ZL, Germany and Spain. There was a very quiet but readable portable station in Florida, VE2MW. He was the first operator I heard who was \u0026lsquo;only\u0026rsquo; running 100 watts into a modest antenna. Everyone else I heard discussing their station had big beams and high power.\nA little later I heard a really nice signal from Peter G2YT in England chatting to a VK5 who was running 100W into a mobile whip. From the conversation it sounded like Richard VK5ZRY had initially made the contact with only 2.5W, so that cheered me up a little and I decided to have a go.\nI heard a Spanish station Juan, EA5CTE finishing up a QSO with a ZL, so keen for my first ever HF contact I answered his CQ. He was clearly struggling to make me out, but after several tries with a partial call we got through our calls, names and a signal report. Since I was obviously such a small signal at his end I was very grateful - Juan persisted; getting me to repeat things long after I guess most would have given up.\nAlmost immediately after this I tuned back up to where I had heard Peter \u0026amp; Richard and they sounded like they were finishing up. I glanced over at my tuner, wondering if I\u0026rsquo;d need to retune, then remembered: I hadn\u0026rsquo;t reset my power after tuning - I\u0026rsquo;d completed my first HF contact with Juan in southern Spain on only 5W! No wonder the poor bloke had to work so hard to make me out. I feel bit bad about it.\nLesson 3: Although it\u0026rsquo;s good practice to tune up with low power, you need to wind it up again after.\nAs I set my radio back to 100W, Richard signed off and Peter called CQ. I answered and was thrilled to hear his reply. He had to work a little hard at the start of the QSO (I was 4-4) but we had a lovely conversation and he was suitably excited about being my second HF contact. I think we probably chatted for 15 minutes or so and he struck me as a terrifically nice guy.\nSo, all in all, a great day. My first HF contacts both DX and both operators who were nice enough to work at pulling my mouse-powered signal out of the noise, especially Juan for working an unintentional QRP! I hope to become the sort of skilled and caring operator on HF that these two blokes are.\n","permalink":"https://vk6mib.com/posts/contact/","summary":"\u003cp\u003eI went out for my first shot of HF operating today had had some success as well as learning a couple of lessons.\u003c/p\u003e\n\u003cp\u003eThe set up was at a local lookout - it has a slight elevation compared to town, it\u0026rsquo;s out of the \u003cimg alt=\"Snapped squid pole\" loading=\"lazy\" src=\"/images/img_5439-copy.jpg\"\u003enoise (nearest power-line is about 400m away) and partially surrounded by the salt lake that the town is named for. The lookout has an iron railing that is perfect for strapping my 7m squid pole to. The plan was to hook 20m of wire from that down to the back of the ute and run it as an end-fed.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eLesson 1 - there is only so much tension that can be placed on a squid pole before it snaps.\u003c/strong\u003e\u003c/p\u003e","title":"Contact!"},{"content":"I got another BF-888S in the post today. This one was $18.03 from ebay seller jeenygq. It continues to amaze me that I can buy a frequency agile 70cm transceiver for less than a packet of cigarettes. My ‘reason’ for needing another one is that in addition to my uncompleted 70cm foxhunt project, I’m starting an AllStar Link Node project. I’m always keen to test eBay purchases straight away while they are inside the 45 day PayPal refund timeline, and this seemed to call for one of my other recent purchases – a Rike RK-560 frequency counter.\nPreviously, my only method of testing CTCSS encode and decode has been to program another radio and see if the squelch was opened. This is a bit hit-and-miss as low cost CTCSS chips can often be triggered by adjacent codes.\nThe $29 RK-560 includes CTCSS and DCS decode. It’s about the size of a packet of cigarettes with a single momentary press button on the side, a two line eight character LCD and a 5cm extendible antenna. Mine is in jungle pattern camouflage. I’m never sure if this is an Asian fashion statement or part of the US prepper radio movement. I’m not sure of the post-apocalyptic use of a frequency counter, but there you go.\nThe claimed frequency range is 50MHz to 2.4GHz, and it takes a standard 9V battery that you have to take the back off with a screwdriver to access. My first battery ran down pretty quick – I suspect the button has been inadvertently pressed jiggling around in my backpack. There is a small hole in the back of the case that you might imagine is aligned with a reset button, but the board underneath is unremarkable.\nIn the slow gate setting, the Rike has an error of plus or minus 1 KHz compared to my ACECO FC2002 frequency counter. Operation is pretty straightforward, but as is often the case, the manual was of little use. What I’ve been able to deduce:\nTurn on: With the unit off press and hold the button for about 0.5 seconds. The display come on and toggles back and forward between the two gate speeds. When you release the button you are selecting the fast gate (1K resolution) or slow gate (0.1K resolution)\nSignal capture: Nothing to do, the unit will automatically hold on a strong local signal. The frequency is shown on the top line of the display.\nCTCSS and DCS decode: Happens automatically. CTCSS seems to take about another quarter second after locking the frequency, it looks like it tries to decode CTCSS first, then if none is found it scans the DCS. The DCS identification can take a few seconds. The code is shown on the bottom line of the display, or it says NOCDTCS. Reset/Un-hold: short press of the button. Turn off: press and hold the button, or wait a minute for the auto-off. While I was playing, I thought it would be worthwhile to document the default frequencies of the BF-888S. It seems likely they are being illegally used in clubs and so forth, and if that is happening it’s also likely they are on the shipped frequencies – although there is no guarantee they are all shipped with the same test set of channels.\nCh MHz Sub 1 462.125 69.3 2 462.225 none 3 462.325 none 4 462.425 103.5 5 462.525 114.8 6 462.625 127.3 7 462.725 136.5 8 462.825 162.2 9 462.925 none 10 463.025 NO51 11 463.125 N125 12 463.225 N731 13 463.525 N331 14 450.225 N023 15 460.324 none 16 469.951 203.5 In the Australian 400MHz plan these channels cover some low power simplex licences (including a number of Kmart stores) and land mobile repeater outputs so, along with the low power and minimal antenna, the potential for interference is not huge.\n","permalink":"https://vk6mib.com/posts/rike-rk-560-frequency-counter/","summary":"\u003cp\u003e\u003cimg alt=\"Rike RK-560\" loading=\"lazy\" src=\"/images/img_5385.jpg\"\u003eI got another BF-888S in the post today. This one was $18.03 from ebay seller jeenygq. It continues to amaze me that I can buy a frequency agile 70cm transceiver for less than a packet of cigarettes. My ‘reason’ for needing another one is that in addition to my uncompleted \u003ca href=\"/baby-fox/\"\u003e70cm foxhunt project\u003c/a\u003e, I’m starting an \u003ca href=\"https://www.allstarlink.org/about.html\"\u003eAllStar Link\u003c/a\u003e Node project. I’m always keen to test eBay purchases straight away while they are inside the 45 day PayPal refund timeline, and this seemed to call for one of my other recent purchases – a Rike RK-560 frequency counter.\u003c/p\u003e","title":"Rike RK-560 Frequency Counter"},{"content":"On the F-Troop net this morning, VK6AS mentioned there was another good pass of SO-50 today. With last weekend’s mistakes learned from, I had another shot at it. I thought I could hear snippets of voice modulation down in the static when the satellite was still at -5º elevation which seemed odd. It wasn’t until about 40º that I got anything readable, and even then it was only for half a second at a time.\nThe pass was almost directly overhead for me, so at the apex I was able to just point the Arrow straight up, and copied VK6AS’s call. I put out a call to him and was thrilled to hear his reply of congratulations. So thrilled in fact that I wobbled the antenna and lost him. I was so frantic from then on trying to find the satellite again that I completely forgot to keep adjusting my downlink and didn’t copy anything for the rest of the pass.\nMy Wouxun KG-UV920P arrived yesterday, so I’m finally on 70cm at home. I only have a 2m coax dipole antenna (a WARG made pogo-stick I purchased at HARGFEST ) up at the house, but I’ve heard they tune up on 70cm, but the radiation pattern is no good – being mostly straight up. That sounded perfect for a very high satellite pass, so I left the squelch open on 436.800 MHz with a recorder running – the idea being that I might be able to hear part of the pass on a recording.\nWhen I eventually converted the audio from the Sony proprietary audio format (after having to download special Sony software and Sony drivers – way to go Sony – never forget Betamax!) I was excited to hear my calls out of the noise. I can also hear some of the voice modulation I heard out in the paddock during the pass, and I kinda think maybe perhaps I can hear some of the other satellite traffic. See what you think.\nAt first I thought that my good signal on the recording proved I was getting into the satellite better than the others, but on reflection I’m wondering if I’m not so sure. It’s not exactly a third harmonic of my uplink frequency, but I still suspect it might have been a local signal. Like a lot of the Chinese SDR’s, the UV920P is a fairly wide range receiver so the front end is not going to be stella. On the other hand, I don’t think I was picking up anything in the very wide range scanner I was using for the downlink, and it was on the same beam as I was transmitting on.\nAs for the voice modulation I heard in the field and on the recording, there are transmitters in town for a Christian FM station and ABC TV. The TV is digital, so I think I was probably hearing the Word. I might try further out in the bush for the next pass to eliminate that problem and the possible local bleed onto the 70cm recording.\nToday went a lot smoother, I parked the ute at right angles to the pass so I could dump my stuff on the back, this was especially useful to leave the downlink scanner where I could read it and change the frequency. Handling the antenna is still the worst problem. I’ve obtained a good tripod, and I’ve been looking at one of the K7AGE videos – it turns out the Arrow has a threaded mounting hole under the handle and he just has a hole in the counter weight that he lines up and joins with the tripod.\nI\u0026rsquo;m regretting not purchasing the duplexer. The theoretical advantage of being able to hear yourself on the downlink is not eventuating for me, so I\u0026rsquo;d be better of with just the HT. I think I\u0026rsquo;ll look into this.\nI got an email from VK6MT to say he had copied me in Katanning soon after I got home, so it was nice to get that confirmation, and I’ve since emailed VK6AS to thank him for the contact and he says he\u0026rsquo;s already logged it on QRZ! So it’s official, I’m a sky-talker.\nUpdate: (7/6/15)\nAndrew forwarded an email from Allen VK6XL. Allen was tracking SO-50 during the pass and forwarded this log:\n30°elev VK6MP Cq call - no response 35°elev VK6AS Cq call - no response 55°elev VK6MIB Cq call - no response 56°elev VK6MP Cq call - no response 57°elev VK6AS Cq call - no response 61°elev VK6MIB Cq call - VK6AS responds \u0026#34;5/9 good work (Adrian?)\u0026#34; 71°elev VK6MP Cq call - no response Zenith passed by SO50 and no more downlinks heard as elevation declines. :-)\n","permalink":"https://vk6mib.com/posts/sky-talker/","summary":"\u003cp\u003e\u003cimg alt=\"Ready for action\" loading=\"lazy\" src=\"/images/img_5125-copy.jpg\"\u003eOn the \u003ca href=\"http://ftroop.vk6.net/\"\u003eF-Troop net\u003c/a\u003e this morning, VK6AS mentioned there was another good pass of SO-50 today. With last weekend’s mistakes learned from, I had another shot at it. I thought I could hear snippets of voice modulation down in the static when the satellite was still at -5º elevation which seemed odd. It wasn’t until about 40º that I got anything readable, and even then it was only for half a second at a time.\u003c/p\u003e\n\u003cp\u003e\u003cimg alt=\"SO-50 pass\" loading=\"lazy\" src=\"/images/passgtracklargegraphic-aspx.jpg\"\u003eThe pass was almost directly overhead for me, so at the apex I was able to just point the Arrow straight up, and copied VK6AS’s call. I put out a call to him and was thrilled to hear his reply of congratulations. So thrilled in fact that I wobbled the antenna and lost him. I was so frantic from then on trying to find the satellite again that I completely forgot to keep adjusting my downlink and didn’t copy anything for the rest of the pass.\u003c/p\u003e","title":"Sky Talker"},{"content":"In February, I attended a meeting at HARG that included a talk and demo by Chris VK6FCGB on using the FM repeater payload on SAUDISAT 1C (SO-50). Satellite work is definitely in my ham radio hobby plan, both because of the technical challenges and my remoteness from other hams here.\nThe repeaters in satellites are usually cross-band in order to avoid the need for large cavity duplexes in these micro satellites (about 10kg mass and 23cm cubed). This is the case for SO-50, having a 2m uplink on 145.850 MHz and downlink on 436.800 MHz. It orbits at about 630 km high and completes an orbit every 97 minutes. Due to it’s immense speed, the Doppler effect on the downlink frequency needs to be taken account of; starting about 10kHz up as it approaches from acquisition and winding up about the same down as it sets.\nIt is allegedly possible to work SO50 with a hand-held radio with the built in whip, but I doubt anyone has much success with that. Certainly not much power is needed so a hand-held is fine, but a directional dual band antenna is highly advisable. I’ve recently acquired an Arrow portable yagi – 3 element 2m and 7 element 70cm for this purpose. The \u0026lsquo;Arrow\u0026rsquo; name comes from the fact that the antenna elements are manufactured from aluminium arrow shafts.\nWith a long weekend Monday holiday (thank you WA day!) and a 73º altitude pass predicted, today was the perfect opportunity to give it a whirl. A bit of planning is required. Several websites such as Heavens-Above and Satview will give you the details of each pass. To also have the pointing information live in the field I also used an app on my iPad (HamSat) and Android tablet (Predict).\nThe Arrow 146-437 has separate antenna connections for each band. This is a good thing as it allows you to listen on the downlink full time with one radio while you transmit on the uplink. I used a scanner to monitor the 70cm downlink, with the settings to allow 5kHz tuning steps. The idea is you are able to hear your own voice from the satellite repeater, this is especially important if there’s no one already on so you can be sure you are pointing in the right direction.\nIn addition to aiming the antenna to hunt out the signal, its necessary to rotate it to the correct polarization. The satellite is tumbling slowly as it orbits, so this is just a matter of constantly rotating the antenna whilst listing to the downlink for the strongest signal. Your arms (I had to keep swapping) get something of a workout.\nSo with two radios, two tablets, a note book, a voice recorder and a compass it was quite a production to get set up.\nI had some success in that I was able to copy a QSO between VK6XLR and VK6AS near the end of the pass. I was surprised that when I transmitted that it completely de-sensed the receiver I was using. As I was packing up it occurred to be to have a careful look at where I was transmitting – I was stupidly transmitting on the downlink, instead up the uplink, frequency – so that’s that mystery solved.\nI probably also need some practice of tracking the satellite, I must have been looking in the wrong place for most of the pass. Certainly, I was surprised each time I looked down at Predict and saw how far SO-50 had moved. I should be able to practice this by trying to track any of the other satellites outputting telemetry in AX25. Predict announces some of the azimuth and elevation information by audio, so another future improvement might be to make a little mixer so I can hear both on my headphones.\nI also found myself juggling a fair bit of gear, in particular I was not happy about dangling my transmitter by the antenna socket while I adjusted the downlink frequency on the scanner. I might program one of my BF-888S\u0026rsquo;s for the receiving job. As they don\u0026rsquo;t have a display, they have a voice announce of channels (in English or Chinese!) That way I could leave it on my belt. It would also avoid the problem I had with the scanner buttons getting pressed as I shoved it into my pocket. If I make my transmitter coax a bit longer, that can clip on to me as well, and I\u0026rsquo;ll use a speaker microphone.\nThis was fun, and I feel I’m not far off having some success, so I will definitely be doing some more of this. I just have to wait for another high SO-50 pass on a weekend!\n","permalink":"https://vk6mib.com/posts/space-adventures/","summary":"\u003cp\u003e\u003cimg alt=\"saudi-oscar-50\" loading=\"lazy\" src=\"/images/saudi-oscar-50.gif\"\u003eIn February, I attended a meeting at \u003ca href=\"http://www.harg.org.au/\"\u003eHARG\u003c/a\u003e that included a talk and demo by Chris VK6FCGB on using the FM repeater payload on \u003ca href=\"http://www.amsat.org/?page_id=1015\"\u003eSAUDISAT 1C\u003c/a\u003e (SO-50). Satellite work is definitely in my ham radio hobby plan, both because of the technical challenges and my remoteness from other hams here.\u003c/p\u003e","title":"Space Adventures"},{"content":"I like measuring things, this is perhaps best illustrated with this photo of the current contents of the second drawer in my kitchen. Apart from the usual cooking implements, it contains an infra-red thermometer, a compass, luggage scales, gas bottle scales, 10.5 GHz dopper speed gun and a Geiger counter. I also own numerous electronic meters of various kinds. My most esoteric measuring device is probably a Brix sugar refractometer (uses the bending of light to measure the concentration of sugar in a liquid).\nSo it caused great excitement here when my antenna analyser arrived this week. At over $300 it’s my most expensive piece of equipment in the hobby. I purchased it on ebay, from a seller I’ve dealt with before and it took about exactly a month to get here due to some story about the stock they had being damaged. To their credit, they air freighted it when they finally had stock.\nIt covers 160m to 70cm and is basically a signal source with a frequency counter and a SWR meter. This makes it simple to look at the SWR of an antenna over any range of interest. Previously I’ve had to do this by stepping through the frequencies of interest with my UVB5 handheld on the low power setting, then for each frequency, calibrate my Revex SWR meter and read the result from an analogue scale. This is potentially harmful to the radio, and potentially interfering with other users. I live many miles from my nearest licensed amateur, and I checked for any passes of satellites with 2m uplinks each time, so the risk is small, but still, I liked the idea of the analyser that only uses a fraction of the power to make it’s measurements.\nI excitedly hooked it up to a Chinese dual-bander (Nagoya NL-77BH) I had on a little mag base. Here is the plot I made painstakingly in Excel.\nSo far so good. That’s the sort of curves I was expecting, I was a bit concerned that the usable portions of the 2m band were 132-135MHz and 150-155MHz, since I was sort of hoping to use it in the FM portion I’m licensed for 145-148MHz. However, before this whip is condemned, I haven’t trimmed it (it came with the Allen key to allow for this) and I was measuring it on a 3” magnetic base, sitting on the coffee table inside my steel frame house – not exactly the ideal installation conditions. A better set-up would be mounted on an SO-239 mount installed in a hole the centre of my ute roof and carefully grounded.\nWith this in mind, I tried a variety of other situations. It’s a piece of cake to do – I could just walk around with the antenna connected to the analyser and read off the SWR. The frequency displayed does drift quite quickly, so each time I moved it, I spent a few seconds carefully adjusting the oscillator frequency. I chose 147.000MHz as my frequency of interest, In practice because of the finicky-ness of the frequency adjustment, and the speed of the drift, the measurements were probably about +- 20 kHz.\nCoffee Table 2.4 Coffee table on Baking Tray 3.9 Dinning Room table baking tray 2.9 Dining room table 2.1 Concrete driveway 1.6 Concrete driveway with baking tray 1.9 Centre of ute roof in porch 2.8 Centre of ute roof in driveway 3.1 Centre of ute roof in driveway bigger mag base 2.6 End of dining table, small mag base 1.3 Centre of dinning table 1.6 End of dinning table 1.3 So – interesting. I was expecting on the large (about 5”) magnetic base on the ute roof, parked a couple of wavelengths from anything to be quite usable, but no. Also interesting was the difference in the readings at the centre of my wooden dining table to the end of the table My guess is the extra meter of coax laid out perpendicularly is helping as a counterpoise. Also that’s the sort of positive effect I was expecting from the baking tray as well. Possibly, baking trays need to be earthed to the coax braid for permanent dining room table installations of dual-band whips, that\u0026rsquo;s my recommendation anyway.\nOf course, another possibility is the meter is lying. I was half-hoping that it would have a big frequency error so that plot would move to the left and the antenna under test would turn out to have a solid 5MHz usable right in the 2m band.\nI used to do a little work with radio in a previous work life and have some basic test equipment, including a portable frequency counter so I dug it out. I’ve never had it professionally calibrated, but have tested it against several commercial radios over the years and always found it agreed with the claimed frequencies within a few hertz on the slow gates. With the antenna still on the end of the dining table, I took a number of readings. On average the frequency counter was reading 45 kHz higher than the AW07A. That’s a significant error, but one I feel I can live with, and not enough to make my plot look good.\nAnother possible error is in the SWR readings. I own an old Revex W560 Power \u0026amp; SWR meter, so with the same antenna position, I hooked up the Baofeng to that, calibrated it on 147 MHz and tried to read the SWR to see if it matched the 1:1.3 being reported by my new analyser. For some reason, I couldn’t get a reading, and I actually checked the instructions to ensure I was doing everything correctly, until I realised the meter wasn’t moving when I was looking at the SWR because it was 1:1! Putting the baking tray back to mess it up soon established this was the case.\nSo now I had two devices telling me different things, with a SWR difference from 1:3 to 1:1. This is not a big deal in practical terms, but if this is across the scale it is considerable (for example the difference between 1:1.5 and 1:1.8 is important. However, this doesn’t really tell me which one is wrong. I have faith in the Revex, but it’s just faith, not science!\nThere isn’t much I could do without visiting another amateur with better gear (rare in these parts). I briefly considered constructing a perfect reference antenna for 147 MHz, and may still do that in the future (in conjunction with visiting another amateur with good test gear). I do have a 30W dummy load, so I thought that was worth looking at. The Revex reports it as 1:1 at 147 MHz, whereas the AW07A claims it has a 1:1.2 SWR. It’s not looking good for the AW07A.\nSo now I have a difficult decision. I can send the new meter back, and save my money for a better quality one (perhaps a MFJ-269C or Comet CA-500). The problem is both of those are so expensive I feel I can’t justify them. You can get much cheaper analysers that only cover the HF bands, but I expect that most of my fiddling will be a VHF \u0026amp; UHF.\nAnother possibility would be to home brew one. I was listening to an old Solder Smoke this morning, and Bill Meara was discussing a DDS chip – the AD9805 I think, that can easily be controlled by an Ardunio and could therefore easily be put into service as a frequency generator. The schematic for my Revex does not look too complex so it should be possible to put together something better than I could afford to buy. This also opens up the tantalising idea of being able to data log plots like the one I made above by hand.\nMy guess is inertia will cause me to hang on to the Feature Tech AW07A in the hope that I can somehow calibrate it’s results against some good gear and end up with a usable discount analyser.\n","permalink":"https://vk6mib.com/posts/aw07a-antenna-analyser/","summary":"\u003cp\u003e\u003cimg alt=\"Kitchen Drawer\" loading=\"lazy\" src=\"/images/img_5072-drawer-resized.jpg\"\u003eI like measuring things, this is perhaps best illustrated with this photo of the current contents of the second drawer in my kitchen. Apart from the usual cooking implements, it contains an infra-red thermometer, a compass, luggage scales, gas bottle scales, 10.5 GHz dopper speed gun and a Geiger counter. I also own numerous electronic meters of various kinds. My most esoteric measuring device is probably a Brix sugar refractometer (uses the bending of light to measure the concentration of sugar in a liquid).\u003c/p\u003e\n\u003cp\u003eSo it caused great excitement here when my antenna analyser arrived this week. At over $300 it’s my most expensive piece of equipment in the hobby. I purchased it on ebay, from a seller I’ve dealt with before and it took about exactly a month to get here due to some story about the stock they had being damaged. To their credit, they air freighted it when they finally had stock.\u003c/p\u003e","title":"AW07A Antenna Analyser"},{"content":"One of the exciting things in amateur radio at the moment is the unbelievably low price of the Chinese handheld radios. One of the very cheapest is the BF-888S. It’s a 16 channel 70cm unit putting out about 2.5W. I got a pair for $42 from a Chinese ebay seller.\nThese radios are so cheap, they make you want to invent projects to use them. One project I’ve had in mind for a while is to use them for ARDF/fox hunting (you hide a transmitter, and people drive/wander around with receivers trying to find it) with kids armed with little Yagis.\nAll this would need would be a little programmable logic board plugged into the speaker/mic plugs so the transmitter could be keyed up and play the CW tones required to output my call sign.\nSome variant of Aduino is probably the obvious choice to run this sort of application on for me. Although it could be done on something even simpler, I also have in mind to build an Arduino TNC on a very similar circuit, and that will need a bit of grunt.\nI worried a lot about the TX/RX interface, and looked at many circuits on the internet that used 600 ohm transformers on both to isolate the radio from the electronics, one circuit went as far as using opto-isolators. In a conversation with VK6MT when I was looking for advice about this, he suggested “start with the simplest thing that works”. Sounds like good advice.\nAs mentioned, in parallel with this project, I’ve been thinking about a low cost TNC based on Arduino. This would have exactly the same type of audio/radio interfacing issues. Looking for circuits for this led me fairly directly to Mobilinkd who sell a bluetooth TNC based on an AVR chip for interfacing to APRSdroid. They are good sharers, and they provide a hex file to make your own KISS TNC and have a blog post to explain it.\nThe circuit they show for this is pretty simple (I’m not assuming it’s the same as in their bluetooth verison, but maybe). It has a voltage divider on the sound output of the Arduino to bring it down to 0-500mV and a capacitor to block any DC before it is fed into the mic input on the radio.\nTheir input from the radio audio (which I don’t currently need) also uses a capacitor, then adds a DC offset to the signal to use more of the range of the Arduino ADC. A straightforward NPN transistor is used to switch the PTT to ground.\nThis diagram of their circuit is from M0PZT I plan to use the input circuit eventually, partly for the aforementioned TNC but partly because it opens up the opportunity of remote control of the fox.\nI built it up today on a prototyping shield to test the circuit – pretty much a 20 minute job and had the satisfaction of it working first shot.\nhttps://www.youtube.com/watch?v=nuUJwT6rRpc\nAs you can see it’s currently based on an Arduino Uno, It makes sense to shrink it down to a Nano or Mini Pro eventually. I’ll build it properly onto a blank UNO shield for the time being, and order some PCB breadboards for a mini version. According to Miklor, there is some voltage available in the speaker/mic plug. If there’s enough to run a 3V mini-pro, I could end up with a matchbox sized unit that just plugs straight on the side of the radio.\n","permalink":"https://vk6mib.com/posts/baby-fox/","summary":"\u003cp\u003e\u003cimg alt=\"BF-888S\" loading=\"lazy\" src=\"/images/bf-888-bovenkant.jpg\"\u003eOne of the exciting things in amateur radio at the moment is the unbelievably low price of the Chinese handheld radios. One of the very cheapest is the BF-888S. It’s a 16 channel 70cm unit putting out about 2.5W. I got a pair for $42 from a Chinese ebay seller.\u003c/p\u003e\n\u003cp\u003eThese radios are so cheap, they make you want to invent projects to use them. One project I’ve had in mind for a while is to use them for ARDF/fox hunting (you hide a transmitter, and people drive/wander around with receivers trying to find it) with kids armed with little Yagis.\u003c/p\u003e","title":"Baby fox"},{"content":" I am Ian, VK6MIB. This blog documents some of my adventures fiddling around with radio. My interest in the magic of radio electronics goes back a long way - I built crystal radios with Dad as a kid - but I\u0026rsquo;ve only been a licensed amateur radio operator for a few months.\nI live and work in rural Western Australia as a teacher.\n","permalink":"https://vk6mib.com/about/","summary":"\u003cimg src=\"/images/cropped-cropped-square-radio1.png\" alt=\"\" class=\"about-logo\"\u003e\n\u003cp\u003eI am Ian, VK6MIB. This blog documents some of my adventures fiddling around with radio. My interest in the magic of radio electronics goes back a long way - I built crystal radios with Dad as a kid - but I\u0026rsquo;ve only been a licensed amateur radio operator for a few months.\u003c/p\u003e\n\u003cp\u003eI live and work in rural Western Australia as a teacher.\u003c/p\u003e","title":"About"},{"content":"My club (BRC) is looking at getting in to some fox hunting as a way of creating some shared activities, so I\u0026rsquo;m going to need a simple, portable beam with a good front to back ratio in order to play.\nI had a look around and vk3hra\u0026rsquo;s blog had a nice step-by-step so I decided to copy his. It\u0026rsquo;s based on the fairly common PCV pipe \u0026amp; tape measure approach. The idea with steel tape measure is that it bounces back from being folded, so it\u0026rsquo;s easy to fold the elements for transport etc. Here\u0026rsquo;s his design:\nWhile I was standing in Bunnings looking for PCV pipe, I decided that using a wooden boom would make for simpler construction, so ended up with that, plus a box of self tappers and the cheapest 8m tape measure they had. I probably spent about an hour on it, in no particular hurry.\nI started out with the hairpin match at the recommended 10cm fully expecting I\u0026rsquo;d need to adjust it, and started looking at the SWR across 144-148 MHz (the national ARDF frequency is 145.300 MHz but I want to use it for SOTA and FM repeaters as well). I must have made some building error, because to get the SWR down I ended up with the shortest possible hairpin, basically straight across. Compare the design, with my finished version:\nOn the upside, the SWR looked pretty reasonable by the time I had shortened it to there.\nW and I tested it out in the park with the UVB5 transmitting into a dummy load, and using a scanner as a receiver. It does have a good null to the back and a clear gain improvement at the front about 30-40 degrees wide. For some reason, the null and the forward lobe did not appear to be straight down the boom. I\u0026rsquo;ll need to do a bit of testing on this away from metal fences etc as obviously the direction is going to be important.\n","permalink":"https://vk6mib.com/posts/2m-tape-measure-yagi/","summary":"\u003cp\u003eMy club (\u003ca href=\"http://bunburyradioclub.blogspot.com.au/\"\u003eBRC)\u003c/a\u003e is looking at getting in to some fox hunting as a way of creating some shared activities, so I\u0026rsquo;m going to need a simple, portable beam with a good front to back ratio in order to play.\u003c/p\u003e\n\u003cp\u003eI had a look around and \u003ca href=\"https://vk3hra.wordpress.com/2013/10/12/2m-portable-beam/\"\u003evk3hra\u0026rsquo;s blog\u003c/a\u003e had a nice step-by-step so I decided to copy his. It\u0026rsquo;s based on the fairly common PCV pipe \u0026amp; tape measure approach. The idea with steel tape measure is that it bounces back from being folded, so it\u0026rsquo;s easy to fold the elements for transport etc. Here\u0026rsquo;s his design:\u003c/p\u003e\n\u003cp\u003e\u003cimg alt=\"vk3hra tape measure beam\" loading=\"lazy\" src=\"/images/2m-beam.gif\"\u003e\u003c/p\u003e","title":"2m Tape Measure Yagi"},{"content":"I purchased a UV-B5 for my first radio. In general the cheap Chinese hand held radios are incredible value for money. I assume they are selling thousands into the business market in Asia and that\u0026rsquo;s what\u0026rsquo;s allowing these prices.\nSimilar to the best selling UV-5R, the UV-B5 can transmit anywhere in 136 - 174 MHz and 400 - 480 MHz including being field programmable. A result of this, and their lack of certification, they are only legally able to be owned by licensed ham radio operators in most developed countries.\nThe reason for choosing this model over the ubiquitous UV-5R is a couple of things. One of the common faults of these wide band radios is that the front ends can be easily overloaded. According to Brick O\u0026rsquo;Lore the UV-B5 handles this better than the other radios in this price range.\nThe other thing I really like about it is the tuning knob. I\u0026rsquo;m quite interested (in part because of my remote location) in getting in to satellite. A requirement for this is the ability to easily change the frequency as doppler causes it to change during the pass. I\u0026rsquo;m guessing that\u0026rsquo;s be a lot easier to do with a knob rather than up down buttons when I\u0026rsquo;m juggling the yagis to keep them correctly lined up and polarised.\nOne short coming for some users is the five character limit for the memory display names. The radio is quite dated, having come out in 2012, so another possible problem is that spares such as batteries will be much harder to get than for it\u0026rsquo;s more popular sibling. I had a look to purchase a spare battery on ebay, but since for $20 more I can get an entire second radio that\u0026rsquo;s probably the plan.\n","permalink":"https://vk6mib.com/posts/baofeng-uv-b5/","summary":"\u003cp\u003eI purchased a UV-B5 for my first radio. In general the cheap Chinese hand held radios are incredible value for money. I assume they are selling thousands into the business market in Asia and that\u0026rsquo;s what\u0026rsquo;s allowing these prices.\u003cimg alt=\"Baofeng UV-B5\" loading=\"lazy\" src=\"/images/uv-b5_2.jpg\"\u003e\u003c/p\u003e\n\u003cp\u003eSimilar to the best selling UV-5R, the UV-B5 can transmit anywhere in 136 - 174 MHz and 400 - 480 MHz including being field programmable. A result of this, and their lack of certification, they are only legally able to be owned by licensed ham radio operators in most developed countries.\u003c/p\u003e\n\u003cp\u003eThe reason for choosing this model over the ubiquitous UV-5R is a couple of things. One of the common faults of these wide band radios is that the front ends can be easily overloaded. According to \u003ca href=\"http://www.brickolore.com/2013/01/baofeng-uv-b5-best-kept-secret.html\"\u003eBrick O\u0026rsquo;Lore\u003c/a\u003e the UV-B5 handles this better than the other radios in this price range.\u003c/p\u003e","title":"Baofeng UV-B5"},{"content":"I was looking on ebay for radios and saw some old QSL cards being sold. This inspired me to design my own while I wait for my licence to come through. I really love the look of these old cards, the typefaces and cardboard remind me of the wool consignment books in which we used to record details of each bale of wool during the early nineteen seventies.\nAfter a bit of fiddling around in Seashore I had what I was after. I do feel a little bad for poor old Tassie. They don\u0026rsquo;t get left off things so much these days, but it must still grate. I\u0026rsquo;ll have to design another if I ever have a QSO with an apple islander. It might actually work better to shrink the map and have more room for writing around the outside.\nI was tempted to use MC (Megacycles) instead of MHz, but that just seemed a bit too hipster, and a bit hard on Mr Hertz, to whom this hobby owes a bit.\nI sent the design off to Atanas LZ1YE for printing. His washed out pastel card colours probably the closest to the speckled cheap cardboard look I\u0026rsquo;m after.\nI\u0026rsquo;m having this lot done on the burnt orange colour, since that seemed very Australian and suited the 1950\u0026rsquo;s vibe I was after. I don\u0026rsquo;t plan on being a big contester or QSL card seeker, but it does seem like a nice thing to post off a QSL card for important contacts or amateurs that are chasing them.\n","permalink":"https://vk6mib.com/posts/qsl-cards/","summary":"\u003cp\u003eI was looking on ebay for radios and saw some old QSL cards being sold. This inspired me to design my own while I wait for my licence to come through. I really love the look of these old cards, the typefaces and cardboard remind me of the wool consignment books in which we used to record details of each bale of wool during the early nineteen seventies.\u003c/p\u003e\n\u003cp\u003e\u003cimg alt=\"vkaxr qsl card\" loading=\"lazy\" src=\"/images/screen-shot-2015-03-08-at-5-03-15-pm.jpg\"\u003e \u003cimg alt=\"vk6yz qsl card\" loading=\"lazy\" src=\"/images/vk6yz.jpg\"\u003e\u003c/p\u003e","title":"QSL Cards"}]