>
>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.
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