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Author Topic: Leaky Coax?  (Read 2458 times)
KG4DZB
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Posts: 1




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« on: September 27, 2000, 09:46:51 AM »

Been very rainy in these parts lately.  Inadvertently gave my underdash radio a good kick the other day and so I reached down to check my connections. Horror! Water drops on the antenna SO-239 coaxial connector.  No underdash leaks, and no water sneaking down the outside of the coax.  Dried the connector thinking maybe I had "kicked" some water up under there, but checked later in the day.  Additional horror!  More water drops.  Replaced the magmount/coax feed.  No more water drops.  So, can coax really wick water (assuming water was getting in at the magmount itself)? Is this just a strange condensation issue?  Or what?  I can't figure it, and would appreciate the collective wisdom of this group.  Thanks.
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AD8K
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Posts: 19




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« Reply #1 on: September 29, 2000, 10:45:21 AM »

Can you spell "Capulary Action?"   I probably can't.

Vic  AD8K
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AC5WA
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Posts: 35




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« Reply #2 on: October 10, 2000, 05:04:49 PM »

AD8K's capliary action comment is probably on the mark.  If water can get into the mount base fitting and the coax is not sealed to keep it out, it can indeed pipe water right into the back of your radio.  If you have a small nick anywhere in the cable jacket, it can also serve as an ingress point and the wicking action begins.  

I repalaced a LOOONG run of coax that had the shield almost completely destroyed by this problem in a marine installation.  One would not think that much salt water would get into a cable running from the bridge to an antena mounted on the tip top of the mast of an oil tanker but it did.  There was a nick in the cable jacket about 3 feet below the antenna where it was cut by a cable clamp. It was so bad the R.O. had cut the cable jacket where it went into the VHF to let the water drain out.

I fill the end of the cable with silicone grease and tape and dope all connectons where I am worried about water.

73 de AC5WA
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