On Mon, 28 Apr 1997 16:49:45 +0000 w8jitom@postoffice.worldnet.att.net
writes:
>Ceramic chips are the way to go now. You can get multi-layer NPO
>type chips that have very low dissipation factors for about $5 each.
>The voltage rating is about 3 kV, and they work very well if the are
>not contaminated during manufacturing.
WHERE????
>I never use ceramic caps of any type in large PA's (5 kW up), I
>prefer large silver mica's.
But not available new at sane prices if you mean the large BC/Mil style
that bolt down. New prices are $60 and up into the $$hundreds. True
Silver Micas are only available up to 500V ratings thru distributors.
Ratings of 1000 and 2000V are special purchases in quantity thru the
manufacturer.....not available to Joe Sixpack.
>Pi's are also a problem when unused turns are not shorted!! I've
>arced an RSC 25 kV bandswitch with only 5 kW and a anode voltage of 5
>kV in a properly loaded pi.
Then how come almost all RSC switches are non-shorting, even in
commercial (not ham) amps? They appear to circumvent the voltage problem
with large spacing and current overkill.
>Letting taps hang loose is asking for switch failures no matter what
>network you are using. It's really not much different than inserting
>a bullet, rolling the barrel and going click.
>From the failures that wander thru my shop I cant tell any
difference....they all short. Makes me wonder if we are all missing
something?
73...Carl KM1H
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