[AMRadio] Re: Parallel capacitors for C1

D. Chester k4kyv at charter.net
Sat Apr 5 11:17:30 EST 2008

Is C1 part of the plate tuning capacitance or part of the loading 

If it is on the plate tuning side I wouldn't  recommend those doorknobs. 
Better to use a vacuum fixed or variable, or a heavy  duty  transmitting 
mica like the ones used in broadcast transmitters.

I think doorknobs are pretty light in rf current ratings.  I have seen them 
explode  like a firecracker when their current rating is exceeded.  They are 
most often used as plate coupling capacitors, or with several in parallel, 
as bypass caps.  The circulating current is  likely to be too high in any 
part of the resonant tank circuit.

Don k4kyv 

More information about the AMRadio mailing list

This page last updated 14 Dec 2017.