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(meteorobs) Still CW mode
>From: Mike Boschat <aa063@chebucto.nsdot ca>
>Subject: (meteorobs) A really weird thing is happening to my radio listening!
> Well, I listen to meteors with an Icom R10 radio with a dipole antenna
> Now, I monitor on CW mode but was getting a hard tone, by accident I found
>the problem, it was my 900 MHz telephone!! when I unpluged the adapter the
>tone went and I heard meteors on CW ok.
>NOW HERE's the interesting part. When I plug the adaptor in the tone
>comes back BUT I can detect meteors on the AM mode! If I disconnect
>the adaptor I loose them onthe AM mode!
>The theory is that for some reason when I plug the 900 MHz phone in
>I'm making the AM mode a bit more "sensitive" and can detect the meteors.
>Have I stumbled on something?
---------------------------------------------------------------
No, you're still receiving on CW mode - but with an *external* BFO.
When in SSB or CW mode, the incoming signal must be heterodyned (beat)
against another signal for the modulation to be utilized.
On AM mode, this isn't necessary, for the signal itself has its own
"carrier" that the modulation beats against.
When your wireless telephone is on, it's putting out a weak signal on the
proper frequency that functions as a BFO (beat frequency osc.). The
incoming signal from the meteor ping then beats against the weak telephone
signal to produce the tone.
(It probably won't be as sensitive using your wireless fone, for the signal
levels probably won't be well balanced. But it can work, and is an old trick).
73, Shelby, W8WN
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