Around my location, there is an odd signal near 50.145MHz (at this moment it seems centered around 50.14735MHz but that changes as the day progresses). Other amateur radio operators in this city also hear it; apparently it started about a year ago.

I am curious where it is coming from but do not have equipment for 6m fox-hunting. There was something written once about using existing web-SDR stations to triangulate signals. Is such a thing really practical? If so, how would one go about doing that?


I suppose that a very rough estimate of the general location of the transmitter could be made by comparing signal strengths of several receivers with omnidirectional antennas without knowing exact details of the antenna systems of the receivers, but the estimate will be very approximate. That's not a very practical technique.

A better technique is to have several fixed stations point directional antennas at the transmitter as best they can, and then triangulate. However this technique can be fooled by reflections, interference, etc., and it's still not exact.

The best way to locate a transmitter is to use "fox hunting" techniques with a portable antenna, a portable receiver, and other such equipment. (An attenuator can be a great help.)

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    $\begingroup$ A 6m Yagi is pretty big (10 feet across the radiator?), a loop or similar would probably be more practical. There are mobile units that can receive the full 6m band, FM or AM, at under $200. Add a battery and loop and you're ready for fox hunting (as long as the signal isn't CW or SSB). $\endgroup$ – Zeiss Ikon Sep 5 '19 at 11:22
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    $\begingroup$ Also, a loop can be a multi-band antenna, so it doesn't need to be just for 6m only. $\endgroup$ – rclocher3 Sep 5 '19 at 20:42
  • $\begingroup$ A directional antenna isn't strictly required for fox hunting, although one certainly helps. Just putting one's body between the transmitter and the antenna can make enough of a dip in signal strength to be useful. $\endgroup$ – rclocher3 Sep 5 '19 at 20:55

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