I was listening to Glenn Hauser's excellent shortwave listening show on WRMI this week, and he mentioned a technique that I had not been aware of: listening for the harmonics of distant stations. This is apparently being done for medium wave broadcast stations, but also for stations in the lower frequency range of the shortwave bands. If propagation makes it highly unlikely for you to hear the main frequency, perhaps propagation would be better for the the second or third harmonic. This method is discussed here:
http://www.pateplumaradio.com/genbroad/harmonics.htm
Here is some more background information on Glenn Hauser:
https://en.wikipedia.org/wiki/Glenn_Hauser
Here is a real treasure trove of articles and recordings about the history of shortwave radio:
http://www.ontheshortwaves.com/history.html
AHA! That's quite likely how I was able to hear (Radio France?) at either end of the dial during my High School years. My old 'side-pin valve' rescued set served me well there: I topped the class! :)
ReplyDeleteAZ1 rectifier (80 / 5Y3 equivalent)
EL3N Audio out (6v6 equiv)
EF and EBF valves for IF and AF amps (not sure which had the det/agc diode)
and ECH3 rf/converter (ECH34 equiv.)
Rescued from local (Napier) repair shop, about to be dumped.The EL3N's cathode resistor had overheated melting its soldered 'earth' connection. A few seconds with the soldering iron and LIFE! :) Not a bad effort for a 13-y-o me. :)