[Elecraft] KAT100 Relay Noise Supression Results

[Logan R. Zintsmaster]

I took a trip to my friendly Ace hardware store and bought a package of
adhesive Felt Blankets  (ACE 54487).  There are two 4.5" by 6" pieces of
3/16 felt with adhesive backing in the package.  I also bought some 3/4"
by 3/16" thick closed cell PVC weatherstrip and began to see how to
soften the relay rattle in my EC-2 enclosure (with the KPA 100).

I put two strips of the felt on the bottom plate just underneath the
relays.  I couldn't put in a single piece because of the tie wraps.  I
also put a piece on the blank area of the front panel and on the blank
panel between the front panel and the KPA 100.  This really took the
edge off of the sound.  It was still there, but somewhat muffled.

I also cut the weatherstripping to fit the sides and tops of the relay
banks. This helped a little bit more but didn't seem worth the effort. 
My guess is that the sound is coming through the relay cases into the
PWB and is then coupled into the case.

Usual disclaimers apply, I am not affiliated with Ace hardware, "your
mileage may vary."

Logan, KZ6O
#1609