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Re: [TowerTalk] re; Whiskers growing where you cannot shave them

To: towertalk@contesting.com
Subject: Re: [TowerTalk] re; Whiskers growing where you cannot shave them
From: Jim W7RY <w7ry@centurytel.net>
Date: Sat, 02 Apr 2005 10:38:40 -0800
List-post: <mailto:towertalk@contesting.com>
Motorola had and issue with whiskers inside of their filter 
cavities(receiver pre-selector and exciter filters) used in UHF base 
stations (MSF-5000). This was also an issue in some mobiles (Mostar). If 
you looked closely, you could see them with the naked eye. Some of the 
pictures that were posted looked exactly like the whiskers that "grew" 
inside of the Motorola pre selectors.  General Electric also had this issue 
with some of their MASTR II VHF receiver pre-selectors.

You would just blow them out with a high pressure stream of compressed air. 
If you were brave, you could spray them with clear Krylon to keep them from 
growing back. It worked most of the time.


This has been a very interesting thread. I now know what caused them.

73
Jim W7RY


The wisker issue is not limited to deep space.At 08:16 AM 4/2/2005, you wrote:
> > Whiskers are an issue in reliability of (usually space)
>components and
> > circuits.  The culprits are Tin >97% pure, 100% pure
>cadmium and 100% pure
> > zinc.  If these metals are NOT pure, there is little
>problem.
>
>
>
>Unless we send our solder joints deep into space or
>otherwise place them in a vacuum for many years whiskers are
>not an issue.
>
>They only form in a high vacuum and it takes a long time, so
>why worry about it?
>
>73 Tom
>
>_______________________________________________
>
>See: http://www.mscomputer.com  for "Self Supporting Towers", "Wireless 
>Weather Stations", and lot's more.  Call Toll Free, 1-800-333-9041 with 
>any questions and ask for Sherman, W2FLA.
>
>_______________________________________________
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>TowerTalk@contesting.com
>http://lists.contesting.com/mailman/listinfo/towertalk

_______________________________________________

See: http://www.mscomputer.com  for "Self Supporting Towers", "Wireless Weather 
Stations", and lot's more.  Call Toll Free, 1-800-333-9041 with any questions 
and ask for Sherman, W2FLA.

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