Sealing

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jazzboypro

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Hello,

I have a comet GP-3 antenna than i will be installing in a few week. I have sealed the main element with Temflex and Super 33+ electrical tape. That antenna has 3 horizontal radials that screw in the main element. I would like to seal the joint where the radials are screwed in the main body of the antenna. i don't think that tape is the proper solution for those tiny joints. Any recommendation as one i could use ?

1616177061906.png

Thanks
73
VA2FCS
 

K4EET

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Like @iMONITOR said, those radials are part of the ground plane and probably just screw into the metal pipe/housing. You definitely do not want to electrically insulate the threads from the ground. If anything, use an electrically conducting compound but I think you would be better off leaving the threads dry and screwing them in tight until seated. That should seal out any moisture.
 

prcguy

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The threads do not protrude to the innards of the antenna, its a "blind hole". I usually put Burndy Penetrox on those to keep them from corroding together over time. The antennas usually don't leak where you put the tape but I would have put a bead of black RTV silicone around it instead of tape. The place where those antennas leak is on two and three section versions at the coupling nuts. I usually use RTV sealant on the threads and movable coupling parts when I put them together.

Hello,

I have a comet GP-3 antenna than i will be installing in a few week. I have sealed the main element with Temflex and Super 33+ electrical tape. That antenna has 3 horizontal radials that screw in the main element. I would like to seal the joint where the radials are screwed in the main body of the antenna. i don't think that tape is the proper solution for those tiny joints. Any recommendation as one i could use ?

View attachment 100784

Thanks
73
VA2FCS
 

jazzboypro

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The threads do not protrude to the innards of the antenna, its a "blind hole". I usually put Burndy Penetrox on those to keep them from corroding together over time. The antennas usually don't leak where you put the tape but I would have put a bead of black RTV silicone around it instead of tape. The place where those antennas leak is on two and three section versions at the coupling nuts. I usually use RTV sealant on the threads and movable coupling parts when I put them together.

Thanks pcrguy, there was already some silicone where i put the tape, i just added additional protection just in case.
 

Golay

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Are RTV silicon sealants corrosive?
The better question is "Are RTV silicon sealants conductive?".
It's been a few years since I've read about this. But it used to be there was sealants and RTV floating around that would be open at DC becoming conductive at RF frequencies. If I remember right, it took awhile to figure out what was going on.
 

jonwienke

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This stuff is better than any silicone for electrical stuff. Totally non-corrosive and non-conductive, and you can lube up a connection with it before tightening the screw(s) down, and it doesn't bork the conductivity of the joint. I've used it successfully to seal exterior PL-259 connectors, and it works great without causing any weird SWR issues, although you will need a good pair of pliers to unscrew the connector shell once it's dried.
 

WB9YBM

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Hello,

I have a comet GP-3 antenna than i will be installing in a few week. I have sealed the main element with Temflex and Super 33+ electrical tape. That antenna has 3 horizontal radials that screw in the main element. I would like to seal the joint where the radials are screwed in the main body of the antenna. i don't think that tape is the proper solution for those tiny joints. Any recommendation as one i could use ?

I've done the same thing plus added a clear coat sealer (brand name of Krylon works well) over everything. Might want to wash it with window cleaner first & let it dry thoroughly to make sure it's clean...I've had my antennas last 10+ years by doing this...
 

prcguy

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I've had black silicone adhesive react at HF frequencies, possibly due to carbon as the pigment. I would avoid black silicone sealant on anything near RF. On silicone sealants being corrosive, yes and to varying degrees. Most have acetic acid but few have it at a level to be concerned about.

Many years ago the SGC company that makes auto tuners and crappy radios changed the brand of sealant they use inside the auto tuners to hold down coils and to seal the unit up. A guy bought an SGC tuner during this time and it stopped working prematurely and when we opened it up the pungent smell nearly knocked us over and everything inside was corroded and discolored.

The same sealant used outdoors might have been just fine but squirted onto stuff then sealed inside a container was a bad idea for the particular brand and type they used.
 

merlin

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I just use 3M marine grade compound on connectors and mating places. Non conductive, RF proof, displaces any water, never hardens. Pack your connectors and wrap with sealant tape and good for a few decades.
 

jazzboypro

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Very interesting info. I think i will leave it as is and see what happens.
 

N4GIX

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The place where those antennas leak is on two and three section versions at the coupling nuts. I usually use RTV sealant on the threads and movable coupling parts when I put them together.
I've done the same, but then added 1.5" shrink tubing to cover those joint connectors.
 

cistercian

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For sealing coax and wire splices try scotch 2228. It is a rubber tape that welds to itself. It is like
coax seal but thicker and wider. It is fantastic for protecting from water. Lowes has it! Much better than
vinyl tape that seals poorly and ages fast in UV. Scotch 33 is not a good choice for long lasting service.
 
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