[TowerTalk] Antenna switch isolation?

Jim Thomson jim.thom at telus.net
Sat Jun 5 05:48:55 PDT 2010


Date: Sat, 05 Jun 2010 08:27:27 -0400
From: Pete Smith <n4zr at contesting.com>
Subject: Re: [TowerTalk] Antenna switch isolation?

Another trick to consider is arranging the relays so that there are two 
sets of open contacts between ports.

BTW, it is quite amazing how little relay capacity is really required 
for a legal limit antenna switchbox - Top Ten, for example, uses a NAiS 
relay that costs about $2 a pop.  I have tried to break these running 
really high SWRs at 1200 watts - without success.

73, Pete N4ZR

##  what is the CCS current rating of the top ten relays ??   The usual deal
is they are rated at dc/60 hz.... and  really drop off on 10m band. 

##  relays  with ..'10A'  contacts   usually have problems on the upper bands... somedo
some don't.   A good way around that is to use a DPDT relay.. then parallel all the contacts.
Then you quadruple the power rating.. since you doubled the current rating.   Of course the V
rating does not change. 

later... Jim  VE7RF



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