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[TowerTalk] Matching capacitors

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Subject: [TowerTalk] Matching capacitors
From: (George Claussen)
Date: Tue, 10 Aug 1999 03:23:39 +0000
Interesting indeed, Drake did not take shortcuts! One advantage to 
the "PC-Board Capacitor" is the very low inherent inductive reactance.
However one problem in homebrewing such a beast is trying to find out
the characteristics of the insulating material. (Dialectric constant,
puncture voltage, etc.) I sure would be skeptical of the garden variety
flea-market stuff out there if the intended purpose required a nice high
"Q" or needed to withstand high RF voltages. BTW, VE3ERP has written a
neat DOS/Basic based set of routines which make it very easy to crunch
the numbers for designing cap's es coils. Software is free, and is 
called "Hamcalc". (George/VE3ERP does ask for a small donation made out
to the Canadian Society for the Blind).  73, George, N7GC, (the OLD ONE)

At 05:32 PM 8/9/99 -0700, Jim wrote:
>Drake uses PC board caps in the L7. The L7 uses a pair of 3-500Z. They use
>one across the plate choke. The plate choke has a tap about 2/3 the way up
>from the bottom. The cap is to stop a series resonance.  They also use one
>for a padder cap for the tuning cap on 160 meters. It is about 1.5" by 2.5".
>The value of this cap is 300pf.
>Thought is was intresting that Drake did that.....
>73 and good luck!
>Jim W7RY

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