[TowerTalk] Relay Specs -Coax Switch

[Pat Barthelow]

Hello Tom, Keith, and group.

I went searching the web for some relay images to post and have some experts 
view them and comment on the plusses and minuses relative to High Power RF 
use, of the various designs. I found quite a few pictures on the web, which 
I may post for viewing and feedback from the experts.

I also remember in the W6AM Biography book by Jan Perkins, that Don Wallace, 
W6AM had humongous numbers of big antenna relays for his Rhombic Farm
that he had to modify to make less lossy at HF...Very interesting book...

BUT what I also found is mind boggling and I think of interest to many of 
us, especially in this time of (apparent) change towards no-lead solders.  
Check out these NASA and related sites and what they document with respect 
to tin whiskers and the damage they do, esp to high rel (space) systems.

http://nepp.nasa.gov/whisker/photos/
http://nepp.nasa.gov/whisker/photos/relay/ng/relay-armature2.jpg
http://nepp.nasa.gov/whisker/photos/relay/ng/relay-armature1.jpg
http://nepp.nasa.gov/whisker/photos/relay/gsfc/whisker2.html
http://nepp.nasa.gov/whisker/photos/relay/gsfc/whisker3.html
http://nepp.nasa.gov/whisker/photos/waveguide/2004-waveguide-tin-whiskers01.jpg
http://nepp.nasa.gov/whisker/photos/waveguide/2004-waveguide-tin-whiskers05.jpg
http://nepp.nasa.gov/whisker/photos/waveguide/2004-waveguide-tin-whiskers02.jpg
http://nepp.nasa.gov/whisker/photos/waveguide/2004-waveguide-tin-whiskers02.jpg
http://nepp.nasa.gov/whisker/anecdote/20year/index.html
http://nepp.nasa.gov/whisker/failures/index.htm

There are also Ziinc whiskers that did damage, that came from: Floor tiles, 
of all things...
A paper within these listings documents quite a few million dollar plus 
satellites destroyed by these teeny tiny tin whiskers...
Fascinating, and scary if you are in the space electronics industry...

73, DX, de Pat Barthelow AA6EG aa6eg at hotmail.com