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Re: [Amps] New FET's

To: n4zr@contesting.com, w5lu@hotmail.com, craxd1@ezwv.com,Amps@contesting.com
Subject: Re: [Amps] New FET's
From: G3rzp@aol.com
Date: Thu, 10 Feb 2005 08:38:37 EST
List-post: <mailto:amps@contesting.com>
Semiconductors to MIL Spec for space use are MIL 883 level S. They are made  
in the same way on the same production line as the common or garden commercial 
 variety (in most firms, anyway), but just get a lot of extra inspection, 
which  tends to be what costs. How much extra reliability you really get is 
probably  arguable in any one case, although averaged over a lot of units, it 
should show  up. 
 
But one of the OSCAR satellites had a command rx which used a Plessey  
SL6640, and that was not only a standard part, but it came from some unmarked  
devices which had been kicking around in a box in an engineer's drawer for some 
 
years, and not even the batch number was known! This was because a launch was  
offered at short notice, and the design was for a SL6640: the device was  
obsolete, and there wasn't time to redesign and test the rx. 
 
Worked perfectly until the satellite eventually burned up on  re-entry......
 
For prices, you should also try parts for implanted medical devices like  
pacemakers. A crystal ordinarily costing $2  comes in at about $15......a  
1000pF 
X5U chip capacitor in 0204  size is around $2.
 
73
 
Peter G3RZP
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