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As a bit of curiosity, I was wondering what the longest path ever used by amateur radio operators has been.

Of course the opposite side of the Earth is no problem with a good HF station. And you can work long-path, so that's at least the circumference of the Earth.

EME contacts are an even longer path, even if the stations aren't as far apart.

A longer path would seem to require reflection off a natural satellite (doesn't seem feasible) or via an artificial satellite with amateur radio equipment. Have any of the few artificial satellites to have left Earth orbit had any amateur radio equipment? Or is there some other mechanism I'm not considering?

To be clear, receiving telemetry from any artificial satellite with amateur radio equipment does not count. I'm talking only about communications in the ham bands, intended to be used by the amateur radio service.

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  • $\begingroup$ This reminds me of the wonderful story that emerged recently of Larry Baysinger W4EJA of Louisville, Kentucky receiving and recording VHF signals directly from the Apollo 11 astronauts on the moon in July 1969, but those signals were not intended to be used by the amateur radio service. $\endgroup$ – rclocher3 Apr 21 at 22:06
  • $\begingroup$ I wonder if a dual band "big gun" EME station has ever operated as a cross-band repeater between 2 other smaller EME stations. $\endgroup$ – hotpaw2 Apr 21 at 22:56
  • $\begingroup$ Venus at closest approach is "only" 100 x as far away as the moon, so about 80 dB harder. Does a big EME station have an 80 dB margin? I have new respect for planetary radar. $\endgroup$ – tomnexus Apr 22 at 4:25
  • $\begingroup$ Correction - Venus is 67 dB weaker than the Moon because of the moon's much smaller RCS; $0.009\pi a^2$ at 3.6 cm, while Venus is $0.2\pi a^2$ $\endgroup$ – tomnexus Apr 22 at 13:11
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    $\begingroup$ Would you include those controversial Long Delay Echos (LDE)? One claim is that they're multi-orbits of the earth. Don't know if the timing of the echo supports a count of orbits. $\endgroup$ – glen_geek Apr 22 at 18:34
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AMSAT-DL has heard their own echoes on an Earth-Venus-Earth path, on the 13cm band, with the help of the 20-meter dish at Bochum Observatory. It falls a little short of "communication", but it seems that, given two stations with 20m dishes, a Venus-bounce QSO using QRSS, or perhaps one of the slow FSK modes (FST4?) would be achievable.

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  • $\begingroup$ I have no idea how much transmitter power they were using. If anyone is able to find that information, please fill it in :) $\endgroup$ – hobbs - KC2G Apr 22 at 5:24
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    $\begingroup$ Looks like 5 kW amsat-dl.org/en/… $\endgroup$ – Phil Frost - W8II Apr 22 at 15:40

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