[TowerTalk] Protecting a Tower Relay Box

[Jim Thomson]

Date: Wed, 18 Aug 2010 05:04:38 -0700 (PDT)
From: GALE STEWARD <k3nd at yahoo.com>
Subject: Re: [TowerTalk] Protecting a Tower Relay Box
To: TowerTalk at contesting.com, Mark Robinson <markrob at mindspring.com>
Message-ID: <943739.63877.qm at web50706.mail.re2.yahoo.com>
Content-Type: text/plain; charset=iso-8859-1

I'll add my comments which agree with the others advising you NOT to mount the relay box 80ft up the tower. I had to climb my tower once at dusk during the CQWW CW contest to swap out a failed relay box. At least I had a spare. By the following weekend, I had it mounted down at 5ft! It takes a few more coax runs but it's well worth it. Even in bad WX, you can repair something if it's at ground level.

GL with the project!

73, Stew K3ND

##  for a simple 1 in, 2 out box..... I'd use a  spdt vac relay..and be done with it.    Then you could install it at the top of the tower..and forget about it. A gigavac GH-1  or G-2  would be perfect for this application [12 vdc coil] 

## as far as the 1 in, 6 out box's go.... IF all the mech  relay's  are of the DPDT type, with all contacts in parallel, you won't have problems.  No RX path is through any of the NC contacts. 
  If I had ongoing probelms with em.. I'd be swapping them out to  a mess of spdt vac relays.  Even if the box is at the bottom of a tower, with all the heat-shrink, tape, etc on all 7 x connector's, it would take
all weekend to fix it anyway.

##  I re-silver plate all the contacts on the mech relays with 'cool-amp' goop.... then apply a thin layer of 'conducto lube'   [ pure grnd up silver powder in grease]  to all the contacts. ]
Then put heat and silica gel  [ dessicant] inside the box.   You won't have any problems  with it.  7/8" heliax is expensive enough as is.  The last thing I want is multiple runs of 7/8"  heliax
going up the tower. 

later... Jim  VE7RF.