[Yaesu] Fw: Silver Mica ap.

[Steve Harrison]

At 08:55 AM 8/3/2008 -0700, Joe Hatvany wrote:
>Does anyone on the list have, or knows where I could buy a 10pF 1000V Silver 
>Mica Capacitor for my old FY-101. I need the cap to replace the 100pF 
>neutralizing capacitor so I can use American made tubes. Please e-mail me at 
>joekb7svi at verizom.net

If you cannot find one, consider making one from a pair of insulated
solid-conductor wires twisted together. You can adjust the capacitance by
the number of turns or the tightness of the twisted wires. If I recall
correctly, about an inch of PVC-insulated wire of about #20 or 22 or 24
gauge wire will give you around 15 pF when twisted to about ten twists per
inch. Since you need 1000 volts insulation, don't twist them too tight or
you'll compress the insulation and it may arc over. Separate the far ends
so they don't arc over. If you find it works fine, you can put a dab of
silicone rubber or cement or epoxy on each wire end. The stability of the
capacitance should be adequate as long as humidity doesn't get too high,
like 90% condensing or something.

We used to do this all the time in the olden days with V/UHF converters and
transmitters. When we needed insulation for a couple thousand volts, we'd
simply put teflon sleeving over the wires or insulation from bigger wire
like ordinary #12 or #14 house wire.

Steve, K0XP