Use LCC or their Brittish equivalents. ( Ask Ian G3SEK )They are made for
tuned circuits and have been used for years in Swedish ship transmitters
instead of variable condensers. Together with those very handsome Swedish
made roller coils. There is a world outside the US and Centrallab, hi!
What values do you need? 73s de Hans SM5KI
----------
>Från: measures <2@vc.net>
>Till: "Nancy & Steve Lawrence" <smlx@earthlink.net>, "AMPS"
><amps@contesting.com>
>Ämne: Re: [AMPS] Loss in doorknob caps?
>Datum: mån 21 feb 2000 05.13
>
>
>>
>>I'm shunt feeding my tower for the low bands. When replacing air variables
>>caps with fixed doorknobs, the reflected power is much greater. Any
>>thoughts on the losses in doorknob caps vs frequency?
>>
>This problem could be caused by using a bypass type cap in a tuned
>circuit app. .
>There are two kinds of doorknob caps. . Bypass / coupling service and
>tuned circuit service. Typically, the largest value for tuned circuits
>is 200pF at 7500v (type 57). Most 500pF and 1000pF doorknobs are for
>bypass/coupling and drift way too much for tuned circuits. In the
>smaller case size, 100pF at 5kV is the largest value for tuned circuit
>use.
>
>good luck, Steve.
>
>--
>FAQ on WWW: http://www.contesting.com/ampsfaq.html
>Submissions: amps@contesting.com
>Administrative requests: amps-REQUEST@contesting.com
>Problems: owner-amps@contesting.com
>Search: http://www.contesting.com/km9p/search.htm
>
>
--
FAQ on WWW: http://www.contesting.com/ampsfaq.html
Submissions: amps@contesting.com
Administrative requests: amps-REQUEST@contesting.com
Problems: owner-amps@contesting.com
Search: http://www.contesting.com/km9p/search.htm
|