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Author Topic: SWR,Verticals and rain and snow  (Read 511 times)
NK8A
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Posts: 24




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« on: March 22, 2008, 01:12:09 PM »

Hello, I have two vertical antennas.One for 40/80 meters/butternut hf 2v,ground mounted, and I also have a Hygain 12 AVQ for 10/15/20 meters that is mounted on the roof:15 feet off the ground. These antennas have low swr when outside conditions are mostly dry. I find that when it rains or snows the swr goes up sometimes on one antenna and not the other. Just wonder what is the cause of the swr going up? Thanks for any information....Dave
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KZ1X
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Posts: 3228




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« Reply #1 on: March 22, 2008, 01:29:20 PM »

Please describe the radial system you use for these antennas.
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KA5N
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Posts: 4380




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« Reply #2 on: March 22, 2008, 01:30:49 PM »

The simple answer is that water changes the tuning of the coils/traps.  One of your verticals has coils open to the air and the other has shielded traps.  Rain should dry off the the open to the air coils quickly.  Of course snow and ice will stick.  The trap housing may get water inside and not drain properly due to spider webs and insect debris.
Allen
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W8JI
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« Reply #3 on: March 22, 2008, 03:24:32 PM »

I've never had that problem with my trap verticals or trap dipoles or trap yagis.

Perhaps you have a marginal ground system?

What type of ground system do you have?
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VA3KUG
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« Reply #4 on: March 22, 2008, 06:01:29 PM »

I have a 5 band trap vertical (Hustler 5BTV) ground mounted with about 60 buried radials. Regardless of weather conditions (dry, wet, snow, etc.) the antenna systems vswr doesn't change. I would suspect a problem with your radial system.

Greg VA3KUG
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W3ML
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Posts: 166




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« Reply #5 on: March 22, 2008, 07:33:05 PM »

I have the 6BTV and when I take the coax off the bottom screw water runs out.

So, it will collect water and hold that water, which will change the swr.

John
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K1WJ
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Posts: 455




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« Reply #6 on: March 22, 2008, 09:11:42 PM »

Seems to only happen when it rains or snows, maybe the uhf/coax connection needs better water proofing.

I've have a ground mounted 4BTV 2 years of service in Michigan, SWR steady, does not change, hope that lasts....

I have an AR-10 vertical the SWR went up after a rain wind / snow storm this winter & has not recovered yet, when warmer (hope soon) will check connector 1st because I used nothing to water proof it.
Before it went 1mhz out of tune, the swr whould change like your describing. The AR-10 is acting long so I know tubes have not slid down.

I am not sure if this is your issue, but proper inspection for water proofing may be in order

Im not familiar with your Hy-gain antennas, maybe someone who has one of these can relate, my Hustler 4 BTV has been very steady on SWR.

73 David K1WJ  
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