Twelve Metres of Wire

2024-09-08 · 3 min read

The first antenna was the telescopic whip on the portable receiver, pointed out of the window, and it heard a handful of the strongest broadcasters and a great deal of hiss. The second antenna, which is the one I still use, cost less than a takeaway and took an afternoon.

It is twelve metres of thin insulated wire, the kind sold for speakers, run from the kitchen window along the balcony rail and then up the drainpipe to a hook under the gutter, roughly in an L shape. At the window end it goes into a small transformer, a 9:1 unun wound on a ferrite core, with the coax from the transformer to the receiver. A second short wire, about four metres, runs along the inside of the balcony wall as a counterpoise connected to the transformer’s ground side. The whole thing is held on with cable ties and is nearly invisible from the street.

The transformer is the part that made the difference. A random length of wire presents a wildly varying impedance to the receiver, and most of the signal was being reflected at the mismatch; with the unun in place the signal strengths on 31 metres went up by about three S-units and the hiss went down. I had read that this would happen and did not quite believe it until I unplugged the transformer and plugged it back in a few times to be sure.

The first week’s log, in UTC, for the record:

18:05, 9,420 kHz, Greek music and announcements, very strong and steady.
18:40, 7,345 kHz, a Romanian external service in English, good signal with slow fading.
20:15, 6,000 kHz, a Cuban station with Spanish music, readable but with a hum from something nearby.
21:00, 10,000 kHz, a time signal with voice announcements on the minute, weak but unmistakable.
05:30, 5,935 kHz, a religious broadcaster in English from across the Atlantic, fading in and out with the sunrise.

Five identifications in a week from a fourth-floor concrete flat with a piece of speaker wire seemed to me a remarkable return, and it is what turned a passing curiosity into a log. The problems I did not yet know about, the noise and the summer doldrums, were waiting, but that first week was all good news.