Wednesday 19 October, 2005, 08:19 - Amateur RadioListening to the 17 and 15 metre amateur bands recently, I was puzzled by a buzzing that occasionally appeared. Centred around 21300 and 18130 kHz, the odd 50 Hz buzz spread over about 30 kHz (which almost wipes out the whole SSB section of the 17 metre band, which is only 57 kHz wide in total!)
A quick web-search and I discovered the IARU Region 1 Monitoring System (the IARU is the International Amateur Radio Union in case you were wondering) who monitor intruders in the amateur bands. To my surprise (I thought these things had died in the late 1980's) the signal is none other than an over-the-horizon (OTH) radar.
But to make matters worse, this particular one emanates from Cyprus and is brought to us courtesy of the British Military base at Akrotiri (see the picture on the right) - my own side! - where there have recently been riots due to the installation of new antennas...
And it seems that Cyprus is not the only one. The Russian Woodpecker is still drilling holes in the amateur bands, and has been joined by Iran who have updated their OTH radar which can apparently be heard on 14000 and 21000 kHz from time to time. There are also some civil radars that occasionally splash against the amateur bands which use HF frequencies to monitor the state of the sea (cold, wet, salty... what more do you need to know?)
The real surprise in all this is that with modern day spy satellites and other surveillance mechanisms, it's amazing that such primitive technology is still useful. Apparently the radars are only used in times of heightened security risk but what with the atrocities of 9/11 in the US (and the UK's much smaller 7/11 bombings in London) I guess risk is high again. Shame. And shame on the British Military for causing all that nasty interference!
Postscript: I was (cough, ahem) checking the frequencies used by the RAF for 'Architect', their HF communication network and lo and behold up cropped the Cyprus radar centred on about 9040 kHz, so they are 'crapping in their own back yard' too!