[TowerTalk] SteppIR vertical

[Jim Thomson]

Date: Mon, 27 Sep 2010 16:10:55 EDT
From: TexasRF at aol.com
Subject: Re: [TowerTalk] SteppIR vertical

And further, if you don't let the housing breathe, that  condensation can 
accumulate and eventually fill it with water.
 
Trying to seal a box like that will never prevent vapor laden atmosphere  
from entering the box but can seal condensation from escaping. Air apparently 
 will travel through much smaller spaces than water.
 
I have seen this process take place inside hollow Heliax center conductors  
and in a few days flood the downhill connector with water droplets. In this 
 case, the answer was sealing the center pin as if it were a water pipe by 
use of  plumbers tape around the center pin before installation.

##  I'm missing something here?  How do u wrap the center pin, without
upsetting the electrical connection.    I had thought abt this moisture problem
inside heliax b4, and had it on my 'things I better check out asap list'..and
never did, clean forgot. 



 
If you could actually totally seal the box in question, you might be able  
to prevent the problem. But, the problem is: you can't. And if you could, 
you  have to evacuate all air from the box otherwise there will be some water 
vapor  and condensation of that. You can't win!

##  I find that Al/metal boxs are far worse for condensation than plastic box's..
like plastic nema  box's.     All my plastic nema box's have a rubber gasket 
 around the lid.    If they are sealed tight, I will put a big package of dessicant inside
the box  [ silica gel]..and also some heat.    Dessicant changed out once per year. 

## weep holes are  a 2  edged sword.  They also allow for high humidity inside the box,
then eventually everything inside gets corroded, including air variables, relay contacts,and
screws that are not SS, etc.   

Jim VE7RF 


73,
Gerald K5GW