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Old April 6th 04, 10:02 PM
David Murphy
 
Posts: n/a
Default Air-dielectric variable capacitors

Hey folks. I've had my license for just a couple of weeks now. The only
equipment I have at the moment is a Ramsey 2m receiver kit I bought years
ago. Largely for economic reasons, I'm attempting to build a 40m SSB
receiver from schematics in the ARRL Handbook. The first item I'm looking
for is the tuning capacitor. I searched through the list of distributors
from ARRL's site, and found some candidates in Antique Electric Supply's
catalog. Here are the notes:

* Ball bearing mounted shaft
* Gear drive vernier
* 1/4" flatted shaft
* Body is 1-1/4" high x 1-1/8" wide by 1-7/8" long.
* 15 plate section @ 200 pf with trimmer
* 5 plate section @ 30 pf with trimmer
* 13 plate section @ 85 pf with trimmer
* 5 plate section @ 25 pf (no trimmer)

They're priced right ($6 each), but I'm brand new to this, so I want to
verify that I can use these. The schematic calls for a 30pF cap. For
multi-section caps like these, are the sections isolated from each other
to effectively be their own component? In other words, can I just hook up
the 30pF 5-plate section and leave the rest alone? (And for future
reference, could I hook multiple sections in parallel to create additional
capacity possibilities?)

Thanks,
David Murphy
AB8SO