[TowerTalk] Shielding of antenna switching/interstation interference

[Pete Smith N4ZR]

I am trying to track down a source of inter-station interference between 
my two radios when using them for SO2R contest operation.

My SO2R antenna switching system is located at the tower base.  Two 
TopTen 6-way relay boxes are mounted on an aluminum plate, as well as 6 
minibox-enclosed A/B relays.  The plate is grounded to my tower ground 
by a short, direct #2 copper wire.

The TopTen boxes are bolted to the plate.  The Miniboxes are mounted to 
it with a pair of metal tapping screws each.

I did not use Noalox between any of these enclosures during 
construction.  My question -- can I rely on the bolts and metal tapping 
screws to make a good connection between the shielding boxes and the 
aluminum plate?  In terms of RF shielding, how important is it to have 
the shield boxes well connected to a common ground?  Would it likely be 
worthwhile to disassemble everything and apply Noalox?  Alternatively, 
should I figure out how to run some sort of dedicated grounding 
conductor among the boxes and down to the tower ground?

TIA

-- 
73, Pete N4ZR
New Articles Daily - the Contesting Compendium at http://wiki.contesting.com
The World Contest Station Database, updated daily at www.conteststations.com
The Reverse Beacon Network at http://reversebeacon.net