Peter Chadwick wrote:
...
>> I believe the '220pf to ground caps' business got used first in the 30L1.
>> The simplified schematic I have suggests that the ratio of grid to
>> filament RF volts were used for establishing correct tuning and loading,
>> which seems a little strange. It may be that approach works with 811As,
>> but I agree with Tom that is isn't a general approach.
>
>Let's look at that.
>
Yes, indeed. Can any of the Collins aficionados out there affirm just how
the 30S1/30L1 "tune" system works? I can remember tuning a 30L1 by the
book, and being told to dip with the Tune cap and then add Loading until
the meter returned to the zero center point, redip, reload, etc. But I
never knew what was being measured or what the significance of the "zero"
point was.
73, Pete Smith N4ZR
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