[ARC5] Zero Beat Question

[Robert Eleazer]

I suppose that what you can do is to tune in the marker signal to the full 1000 cycle tone and then tune it a little more to get the tone lower, creep up on it from one side.  Then set the calibration mark there.  You may be off by maybe 500 HZ or less.  For the radios that the signal generator is intended to calibrate 2 to 3 KHZ is considered to be adequate.

The SG-297 is indeed made by Polrad.  It has output with either no modulation, FM 150 HZ, FM 400 HZ, and FM 1000 HZ.  When you are in calibrate mode there is no modulation.  Deviation can be set at 10 KHZ, 20 KHZ and modulation "volume" adjusted as well.  It also has fixed crystal controlled outputs associated with various radios' IF's.

The mechanical inner workings are fascinating, with direct oscillator outputs controlled by a probe that goes into the oscillator tank and a fine tuning feature for that probe as well.  It also has an amplified and adjustable output.

By the way, the first thing I picked up to look up Zero Beat was the 1965 edition of the ARRL handbook. The results were disappointing; they use the term Zero Beat without defining it, referring to it in the context of a regenerative detector.

Thanks!

Wayne
WB5WSV      
               
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