Needed Info: 100-250 Coil, GD-1B

[Steve Harrison]

Howdy,

I've obtained a great-condition GD-1B from a very kind fellow in
Connecticut; but it is missing the 100-250 MHz coil and manual. I probably
don't need the manual too badly (there isn't much to a GDO, after all!);
but I would like to try to duplicate the original 100-250 MHz coil if
possible. Also, I'm curious about any alignment instructions that Heath may
have had (so the manual might be useful, after all). And, I found the
original 82-ohm cathode resistor shorted with a jumper for some reason. I
want to get this thing halfway calibrated and working on the 100-250 MHz
range in particular to give to a good buddy in Maine so he no longer has
reason to complain "I can't tell if it's oscillating, nor where, if it is!".

SO: can anyone describe to me what the original 100-250 MHz coil looked like?

And, can anyone briefly describe any alignment instructions?

And, was shorting that cathode resistor some mod to enable more consistent
oscillation across the V/UHF range, or what?

Also, what is the claimed value of the two mica DC blocking capacitors
between the tube grid and plate, and the tuning capacitor??

Finally... does the 6AF4 tube have to be in especially-good condition in
order that this GDO operates reliably across the entire range? I recall the
6AF4 was used extensively as the local oscillator in UHF tuners some 30-40
years ago, pre-Nuvistor days. I'm half-tempted to try a FET since I don't
have any 6AF4s left (got lots of acorns for my own Measurements Corp.  GDO,
though!).

TNX Much,

Steve K0XP

Sponsored by the City of Tempe 

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