I recall reading that if an AM radio is tuned to frequency x plus or minus the heterodyne frequency a radio tuned to frequency x will be blotted out. Is this true? If so what is the heterodyne frequency? Will it work with FM?
If you're speaking purely about receiving rigs, POSSIBLY... (but probably only under very specific conditions) for a TX/RX rig, the situation changes drastically.
I'm quite sure you'll find that varies from radio model to radio model. There's nothing "magic" about it - It's just the frequency the designers picked for the heterodyning process. In theory, it could be any frequency the designers care to choose. In practice, there are some limitations (imposed by both the laws of physics, and the available parts to build the beast) on what frequencies can be used with a given reception frequency range to get decent results.
See first answer.
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I am talking about off the shelf transistorized receivers which usually, here at least permit reception of both AM medium wave and FM.
I see no mention of FM in the first answer.
R >
The idea is that the first radio's LO is leaking and will interfere with the signal? I guess I don't see why that wouldn't happen, if the first radio is poorly made and/or the signal is weak.
I think it's usually 455 kHz for AM and 10.7 MHz for an FM receiver, but as another poster said, it's entirely up to the radio's designers.
An FM receiver might be less susceptible to this kind of interference because of the FM "capture effect". Or maybe it would me more susceptible. I dunno.
-- Wim Lewis , Seattle, WA, USA. PGP keyID 27F772C1 "We learn from history that we do not learn from history." -Hegel
Use a brain-cell, dude...
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-- Is the second radio you mentioned the first radio you mentioned?
No. A is driven mad by continual noise from the radio of B. A would like to deter B from keeping his radio switched on all day.
R
My brain cells work OK when applied to matters I know something about. I doubt that your brain cells would be much use in dealing with matters that I know something about however well they may work in relation to matters you know something about. e.g. I imagine that all you know about proving up uranium ore reserves in sedimentary rocks could be writ large on the back of postage stamp.
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