[CQ-Contest] Fw: Bandpass filter

Tom W8JI w8ji at w8ji.com
Tue Jul 10 08:22:48 PDT 2012

>I see the current max data on the pdf pointed out to me, but more spec
> sheets seem to have no data on current data.  Does someone know of a
> listing for 5 or 10kV QRO caps with current ratings?  73, Guy.

Snubber micas are good capacitors, generally they work out better than 
conventional micas in RF systems, but they are not really characterized for 
high power RF applications. Over the years the data sheets have changed. 
Early snubbers somehow got classified with regular mica's, and the detailed 
RF current data that **very sparsely** did appear has now disappeared.

The long and short is, unless the circuit has exceptionally high circulating 
currents, a CDV16 or larger case will work to several hundred watts. Beyond 
that, it is safer with a high voltage multilayer ceramic chip or large 
multilayer mica.

If you want to know the ratings, I'm afraid the only way is to actually 
characterize or test the part yourself. That's what people using the parts 
wind up doing, if they don't chronic field failures.

Otherwise you have to buy a real RF part that is tested and characterized, 
like a multilayer chip. That would be these parts 

or similar parts from the best company for RF parts,  American Technical 
Ceramics. :-) 

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