Re: Ozark Patrol Tuning adjustment question
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Those British vans are searching for tea & crumpet shops! :-)
On Wed, Apr 22, 2020, 9:32 AM Gwen Patton <ardrhi@...
Perhaps our British members might be able to verify if this is how the BBC's roving radio detection vans would locate people who hadn't paid their radio license fees? I've seen pictures of these vans, with DF loops on them, to sniff out scofflaws, and I wonder if that's what they were designed to detect.
"I believe with the 560 pF capacitor switched in the circuit, to parallel it to c1 (the 365 pF variable tuning capacitor) you are on the higher frequency band, and when c11 is not in parallel with c1, you are tuning the lower frequency band. (I hope my logic isn't reversed here.)"
To clarify, with the 560 pF switched into the circuit, the resonant frequency of the circuit with the 1.6 uH tank, will be about 3.7 MHz. With it switched out, the frequency will be about 7 MHz. I listen to the oscillator in another receiver to find where the Ozark is tuned.
I have read that the Paraset regenerative receivers used by resistance in WW2 put out strong signals from their oscillators that Gestapo used to locate the clandestine radios. The operators had to limit their time listening to decrease possibility of being detected ( and executed ).
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