[TowerTalk] Re: your mail

[Jim Pratt]

We used the "plate technique" for years at my place of employment.  Put 
the PolyPhaser on the plate, terminate the connector to the arrestor, 
connect the cable inside the vault to the other side, and ground the 
plate to a single point ground.  Sounds neat...but we have abandoned that 
method in favor of Microflect feedthrough plates with rubber boots.  We 
could never properly WXproof the connectors outside and the buildings 
would always leak.  Also, over time, the temperature would loosen the 
connectors, making for not only a bad RF connection, but a lousy 
lightening ground.  And it was hard to get a pair of pliers onto a 
connector on a fully-loaded plate.
 
We now ground the shield in three places (top of tower, where the cable 
bends 90 degrees at the bottom of the tower and just before where the 
cable enters the donut/boot), run the cable through the nice WXproof 
boot, and have the arrestor just inside the vault hanging on the end of 
the cable.  The ground wire comes in an unused boot and connects to a 
good ground busbar on the wall of the vault.  No more leak problems...

Of course, if you thought the PolyPhaser was expensive, the cost of the 
MFT feedthroughs and boots will amaze you (they ain't cheap).  The plate 
approach will work well, but you will have to keep the connectors tight.

BTW, the PolyPhaser "PEEP"s (their name) never really impressed me, the 
rubber boots seemed to be something like old bike tire inner tubes with 
the rubber sealed around the coax with a hose clamp.  Never tried it, it 
just looked odd...

73, Jim  N6IG


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