2000-03-25
My Pirate Radio Station
Some years ago, when I was still in high school, I decided to start a radio station. Just a few watts, 2 CD players, a mic or two, and a mixing desk. Not content with mono operation, I hacked a stereo multiplex, which was probably a mistake as weak signals get noisy faster with stereo. Still, it was a lot of fun, I was never caught, and I learnt a lot from it.
At the time, the call sign 2 HOT FM was not in use in Sydney, neither was the frequency of 94.5 MHz. This I believe is no longer the case. Now days I could probably get a community low-power licence from the ACA, but in those days of the SMA no such provision existed.
The Hardware
Bits of the transmitter and studio have gone astray over the years. I sold the mixing desk when other interests took my fancy, I believe I got about $200 for it and purchased a CB with the cash. I still have the mics and the RF gear, I used 2 radio mics, one for me, the other for guests.
The exciter was composed of a VCO and buffer, plus a 3 stage amplifier. The VCO has been stripped out for other projects (it worked very well for its simple design, it still rocks actually) the three stage amplifier is show here.
The VCO board connected to the power rails and the MPX signal input (the BNC connector) the buffer output fed into the first stage of the amp.
The 200 mW output of the exciter was fed by coax into a 2 W amp. The output device in this amp was grossly under-speced for the abuse I gave it. I blew them weekly, but at about $3 each it was affordable.
The antenna for the station was a 5/8th wave vertical fed over four 1/4 wave radials. It made a good match to 50 ohms, and was fed using a few metres of RG-58. The physical support for the antenna was a combination of a potted plant, the balcony roof fascia and a length of nylon rope tied to the balcony railing.
The RF system as a whole was terrible, it had to be tuned carefully to avoid parasitics that would otherwise take out TV reception for a block. I've learnt much about RF engineering since then and cringe at how primitive it was, but it did work quite well.
Once it was all tuned up and working the station was heard for several kilometres at full quieting. The fringe zone extended across most of the metro area. My QTH is on the south side of a hill, directly over water, VHF DX heaven, at least towards the south.
What We Played
Well, we are talking about the 90s, so, 90s music.
I can't remember what our exact programming was, but every Friday I would invite anyone I could (mic shy or not) over as guests for the broadcasts. This must have been quite amusing to listen to, and probably refreshing compared to the usual dribble commercial stations air on Fridays. I still have at least one analogue tape recoding of "The DJ Crew" sessions, I should digitize it before analogue technology disappears completely.
We were far from professional, but a great time was had by all. After a few months we even had a phone patch going (even more laws broken!), which became a feature of the Friday programs.
Somewhere along the way I got a girlfriend (perhaps the radio station helped a bit with that! :), got into CB radio, and had to attempt to study for the HSC. The radio station got less and less attention, and fell into disrepair. The Fridays stopped and it was largely forgotten, until I dug out the hardware and took some photos for this page.
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