[R-390] Another possable mod.

[Mark Huss]

There are several modifications that have gained popularity. Among these 
are the SSB mod by Lankford, the receifier mod, the audio mods, etc.
One thing that has been an annoyance for me is the error in frequency 
when switching bands. This is caused by the crystals aging at different 
rates. In my receiver (made in 1955), some of the crystals are over 
50PPM off frequency. One is 200PPM off frequency! The simple cure is to 
use a DFD-3 to convert the mechanical dial with a electronic counter 
display. Then the oscillators, including the PTO being off would not matter.
But while looking around, I ran across some articles on a 'HUFF-PUFF' 
oscillator stabilizer. Seems to me that, as best I can understand it, it 
would make a nice circuit to pull in the 2nd crystal oscillator using 
the 200 khz calibrator as a reference. From what I can gather, this 
might be a simple fix, involving very little circuitry.
Anybody ever give this a try? Anybody? Lankford??
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Some people are like a Slinky .. not really good for anything,
but you still can’t help but smile when you shove them down the stairs.
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