Turn your old fm radio into an airband tranceiver!

[Simonflyer]

this is really cool..Particularly if it works..

[eastmeg2]

I'm not convinced as it's the AM receiver you would have to make operate in the air-band, not the FM receiver as he appears to be doing in this instance.

 

Even tuned into the right frequency, an FM receiver would not give the audible output corresponding to am AM transmission.

 

BUSTED . . . thumb_down

 

 

[techie49]

You will get some reception even using the FM section of the radio as it's never a perfect FM receiver and will demodulate AM too. It wouldn't be as sensitive as a purpose built air-band receiver, but close by the field you'd get something. You certainly would have to rebuild the AM section to get air-band reception as it normally has a maximum coverage up to about 1.75Mhz.

 

Paul Toone

 

 

[eastmeg2]

Having a reasonably good understanding of both modulation techniques, its like they existing in different dimensions from one another so an FM receiver shouldn't be able to make anything of an AM transmission because the frequency is constant, ie the frequency is not modulated and likewise an AM receiver normally wouldn't make anything of an FM transmission because the Amplitude of the signal is not modulated - only the frequency is.

 

But, I've been around long enough to know that unexpected things can happen to create a result, so I called on the brains trust who has worked in microwave radio communications (40 years) including satellite traffic analysis and optimisation for over 30 years.:gerg:

 

Apparently an AM receiver can make something of an FM transmission via a phenomenon called "slope detection" (Nothing to do with race), but there's no way for an FM receiver to make anything of an AM transmission which is what our friends here claimed to be doing. So my previous response is supported.:ilmostro:

 

Cheers,

 

Glen

 

 

[Guest mike_perth]

As an RF tech I agree FM on AM receiver can happen but AM on FM receiver Im sorry but no way.

 

I was going to comment on this before but couldnt remember the correct term for "slope detection"

 

Mike