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[AMPS] Band Switch Heath SB-1000

To: <amps@contesting.com>
Subject: [AMPS] Band Switch Heath SB-1000
From: km1h@juno.com (km1h@juno.com)
Date: Mon, 28 Apr 1997 17:20:14 EDT
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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