In the R L Drake equipment, there was a "tab" which extended outside the
encapsulated VFO (PTO) compartment. This is where you could attach an
NPO trimmer cap and a simple diode switching circuit. The trimmer was
adjusted to provide the desired shift, as Tom mentions. I don't recall
any "shift drift" once that trimmer was set. It only required a few
picofarads, if I remember correct.
I used this method on the T4X, TR4, and RV-4 that I had in my station.
73 de Bob - KØRC in MN
------------------------------------------------------------------------
On 8/23/2011 8:13 PM, Tom Osborne wrote:
>> Then exactly what is the true definition of FSK ?
>>
>> Ed W3NR
> In the 'Olde Days', it was frequency shift keying.
>
> You actualy built a circuit into the VFO that would shift freqency 850 (or
> 170 later) cycles.
>
> There were problems with some VFO's that doubled or tripled to get to the
> higher frequencies. Sometimes you had to built a circuit for each band.
> Lots easier now. 73
> Tom W7WHY
>
>
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