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Author Topic: To weep hole or not to? That is the question..  (Read 363 times)

Offline Kage

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To weep hole or not to? That is the question..
« on: October 12, 2019, 2103 UTC »
Replacing my old EFHW antenna match box I built a few years ago. It progressively climbed in SWR slowly over time until it became unusable.
Took down the vertical today and disconnected the box, opened it up and you guessed it.. water came gushing out.
Thought for sure I had that thing waterproofed well with RTV silicone but the antenna mount bolt is on top so rain ran down the antenna pole on top of that bolt and nut and somehow worked its way through the bolt threads into the box even being on there as snug as I could twist along with sealant.

So would it be advisable to make my new box waterproof with some other method/sealant or have a bottom weep hole to let water out?
This raises another issue in that humidity could get through the weep hole causing its own damage so not sure which is better practice in proofing it.
Luckily my coax didn't get water down it, or not enough to damage it but I definitely checked it with a dummy and meter to make sure and crossed my fingers.
I'm worried if the weep hole is at the bottom which is where my coax will connect that it will let water out which can then drip towards the coax connection. Thinking of maybe gluing a tiny tube into the hole so it runs past the connector

Ugh Midwest weather season is brutal on antennas  ::)
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Offline pinto vortando

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Re: To weep hole or not to? That is the question..
« Reply #1 on: October 12, 2019, 2152 UTC »
Any penetration on top of a "weatherproof" box is a potential failure point.
If you decide to go with a weep hole, make sure it is small enough to prevent entry of yellow jackets, spiders, etc.
Das Radiobunker somewhere in Michigan

Offline Kage

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Re: To weep hole or not to? That is the question..
« Reply #2 on: October 12, 2019, 2227 UTC »
Any penetration on top of a "weatherproof" box is a potential failure point.
If you decide to go with a weep hole, make sure it is small enough to prevent entry of yellow jackets, spiders, etc.
Looks like I typed too soon. After a little reading it sounds like a weep hole is actually required because a perfectly sealed box will build up condensation. After pushing the top of my old match box into a glass of water there was no leak. Looks like the few tablespoons of water in it built up from condensation alone over the seasons since I didn't build it with a bottom weep hole.

Now the question is how large of a hole? My match unit is small since I am using a toroid this time instead of air coil so guessing it won't need to be any larger than a coffee straw opening, small enough to keep bugs out for sure. Wonder if that might be too small?
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Offline pinto vortando

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Re: To weep hole or not to? That is the question..
« Reply #3 on: October 13, 2019, 0914 UTC »
Whether it is condensation or leakage, two 1/8" weep holes in the bottom should work.
Otherwise, if the box is small as you mention, you may want to consider potting the
whole inside in epoxy if it's just a small toroid and no moving parts in a low power QRP or RX application.
Das Radiobunker somewhere in Michigan

Offline Josh

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Re: To weep hole or not to? That is the question..
« Reply #4 on: October 13, 2019, 2156 UTC »
Any size hole is fine as long as it passes air, but put some screening material glued to the housing to discourage insects if the size hole warrants.
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