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.
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!
73,
Gerald K5GW
In a message dated 9/27/2010 2:57:58 P.M. Central Daylight Time,
xdavid@cis-broadband.com writes:
I totally agree. Don't seal holes, especially if the housing is
plastic. Virtually any commonly used plastic is non-hermetic to
individual water molecules, and internal condensation over time (changes
in atmospheric pressure, changes in humidity, changes in temperature) is
inevitable. If you don't let it out, you increase your chances of
internal corrosion.
73,
Dave AB7E
On 9/27/2010 6:06 AM, Kelly Taylor wrote:
> If they are entering from below, I would suspect it's not through a hole
> that is a design flaw, but rather a hole designed as a moisture vent. I'd
> think if that was the case, screening the hole is a better idea than
sealing
> it.
>
> Most of the other vertical antennas with tuning boxes at the bottom
(whether
> mechanical (Steppir) or electrical (R5, R6000, etc) use these holes to
allow
> water to escape. The water isn't from leaks but from condensation.
>
> 73, kelly
> ve4xt
>
>
> On 9/26/10 1:44 PM, "Ryan Jairam"<rjairam@gmail.com> wrote:
>
>> How about some compressed air?
>>
>> I would be wary of cleaning out with any sort of liquid.
>>
>> I would look at sealing it up properly if you think they are entering
>> from below.
>>
>> Ryan, N2RJ
>>
>> On Sun, Sep 26, 2010 at 10:35 AM, Steve Daniel<nn4t@comcast.net>
wrote:
>>> Good morning. I have the 6-40 meter vertical which, until recently, has
>>> worked well. Suddenly, I was hearing nothing. The element seems to
cycle
>>> properly but no signals.
>>> After checking the coax and finding no problem I opened the unit at the
>>> bottom of the antenna to find it full of ants and not a few small
spiders.
>>> The gasket was in good repair so they must be entering from underneath
>>> somehow. My question is this. How can I clean out the mess they have
left
>>> without damaging the motor? Can I use an insecticide to kill the
little
>>> critters? Can I hose out the unit, allow it to dry, try to determine
the
>>> entry point and then plug it? Then perhaps I can determine what the
>>> electrical problem is. I am just not sure how aggressive I can be in
cleaning
>>> the unit. If anyone has any experience or suggestions I would certainly
>>> appreciate the input. 73, Steve, NN4T.
>>> _______________________________________________
>>>
>>>
>>>
>>> _______________________________________________
>>> TowerTalk mailing list
>>> TowerTalk@contesting.com
>>> http://lists.contesting.com/mailman/listinfo/towertalk
>>>
>>
>
> _______________________________________________
>
>
>
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>
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