Getting it up

View of a backyard with a dipole antenna. Feedline can be seen coming down at a 30º angleCommon 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.

I 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. Continue reading

Inkscapades

Bunbury Radio Club BadgeI’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.
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Diamond in the Sky

AW07AI’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.

Fast 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.

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RTS-SDR Sleuthing

Harvey_SW_HighwayYesterday 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.

I 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. Continue reading

The Download

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.

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SSTV

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.

The 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). Continue reading