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Author Topic: Considering a 6BTV verticle but worried about snow build-up at the base.  (Read 3176 times)
KF7YED
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« on: February 03, 2013, 08:51:03 PM »

I've been working off a homebrew attic dipole since I got my license in August, and now I'm considering putting up a Hustler 6BTV verticle. But I'm worried about snow building up at the base.... We get 2 - 3 ft of snow by January and its here to stay until April. (At 6,000 ft in SW MT.) If I install the radial plate with a tilt-over mount, can I elevate the base up off the ground 2 or 3 feet? I know I'd have a wierd looking setup with radials coming down off the base into the ground. Or does that mess up the tuning of the radials?

Or should I just install it as instructed and wade out there to shovel the snow away from it all winter? I ain't getting any younger....!


Thanks,

Rick
KF7YED

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KQ6Q
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« Reply #1 on: February 03, 2013, 09:49:16 PM »

Consider getting a flexible plastic trash can big enough to enclose the entire base and radial connection plate, cut a hole in it to fit upside down over the antenna base area, and use that to shelter the feed area.
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KK5J
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« Reply #2 on: February 04, 2013, 05:45:13 AM »

I agree with KQ6Q. I use a trash bag not a can, but both work. Our snow just doesnt last that long so I can get away with the bag. You can certainly elevate the base and dont worry about tuned radials, once on the ground they are no longer tuned. Elevated base is a bit more hassle, IMO. Going with the can/bag is easiest.
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K5LXP
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« Reply #3 on: February 04, 2013, 06:52:05 AM »

There is nothing electrically at the base of a *BTV that can be detuned by snow (snow is mostly air anyway and is essentially transparent at HF).  The trashcan idea is a good one if there are mechanically sensitive components at the base but in the case of the *BTV, there's nothing there but the base bracket and monopole.  Do not elevate the feedpoint, it will cause tuning problems.


Mark K5LXP
Albuquerque, NM
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NK7Z
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« Reply #4 on: February 04, 2013, 07:04:32 AM »

You may want to consider elevating the antenna...  See:
http://www.steppir.com/wp-content/uploads/2011/10/radial-systems-for-vertical-antennas.pdf
I have a friend who elevated his vertical and it worked MUCH better...  There is a thread here on elevated verticals at:
http://www.eham.net/ehamforum/smf/index.php?topic=66607.0
The general conciseness appears to be that elevated verticals work much better unless you have something like 60 to 100 radials under the ground mounted vertical.  I know I will be elevating my vertical this summer.

73's,
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Thanks,
Dave
For reviews and setups see: http://www.nk7z.net
W8JX
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Posts: 6468




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« Reply #5 on: February 04, 2013, 08:11:56 AM »

There is nothing electrically at the base of a *BTV that can be detuned by snow (snow is mostly air anyway and is essentially transparent at HF).  The trashcan idea is a good one if there are mechanically sensitive components at the base but in the case of the *BTV, there's nothing there but the base bracket and monopole.  Do not elevate the feedpoint, it will cause tuning problems.


Mark K5LXP
Albuquerque, NM

I have used a 5BTV for many year and while we do not get several feet of snow that lasts for months my base is less than 6 inches from ground and has been buried in more than a foot of snow at times with no effect on its operation.
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W5WSS
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« Reply #6 on: February 04, 2013, 08:29:53 AM »

Hello, If you plan on adding a balun with the metal housing and locating it out at the antenna base radial plate or any device that can get water inside then one may benefit from a wx proof enclosure where the balun may be vulnerable to water getting inside and freezing and expanding enough to cause damage.

Usually the PL-259 UHF coaxial connector/s is aligned with the balun and benefits from this as well.

 Powdery low moisture content Snow itself piled up around the base would not be a disaster.
I am not quantifying the subtle effects of the added element H20 frozen or whatever state near the antenna base but under normal circumstances your transmit signal strength is not the issue but rather the longevity of your antenna system.

I do not see any major issues whether one chooses to omit any wx proofing is mostly a function of maximum device longevity in a harsh outdoor environment where the device is usually designed for it.

Including Slightly elevating the ground mounted system on a pedestal block

73



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N0YXB
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« Reply #7 on: February 04, 2013, 08:41:32 AM »

I believe you'll be happy with the 6BTV and there have been some good suggestions mentioned for dealing with snow.  I don't agree with the suggestion that one needs 60-100 radials to make this antenna work well, or else it needs to be elevated.  Mine is ground mounted with 37 radials and I could not be happier.  Follow the directions and put down a decent radial field and I believe you'll find the 6BTV to be a step up from your attic antenna.
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KK5J
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Posts: 82




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« Reply #8 on: February 04, 2013, 08:57:31 AM »

There is nothing electrically at the base of a *BTV that can be detuned by snow (snow is mostly air anyway and is essentially transparent at HF).  The trashcan idea is a good one if there are mechanically sensitive components at the base but in the case of the *BTV, there's nothing there but the base bracket and monopole.  Do not elevate the feedpoint, it will cause tuning problems.


Mark K5LXP
Albuquerque, NM

Mark:

You are correct in that snow itself isn't the problem. For me its the freeze/thaw cycles after the snow that create the problem.
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KF2Q
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« Reply #9 on: February 04, 2013, 04:36:25 PM »

I'm doing the exact thing thing with the exact same antenna under the exact same circumstances... and indeed my concern is the thaw/freeze cycle where the base would end up enclosed in conductive ice around the feedpoint conductor.  My solution is a sliced plastic garbage can of appropriate (to the surrounding ground) color for those three months when I get a couple feet of snow.
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W8JX
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« Reply #10 on: February 04, 2013, 05:37:19 PM »

I'm doing the exact thing thing with the exact same antenna under the exact same circumstances... and indeed my concern is the thaw/freeze cycle where the base would end up enclosed in conductive ice around the feedpoint conductor.  My solution is a sliced plastic garbage can of appropriate (to the surrounding ground) color for those three months when I get a couple feet of snow.

If you are worried about it you could even use a 5 gallon pail. Lot less noticeable and less sail in wind too. 
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W9PMZ
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« Reply #11 on: February 05, 2013, 02:12:45 AM »

Yup.. the snow at the base is not a problem.  Then antenna will continue to work with no problems.

What is the problem is the connection at the base.  Forget a coax pigtail connection!  You will shortly have water logged coax.  Get a connector kit such as the one DX engineering sells, or make your own.  (DX Engineering AOK-DCF - DX Engineering Direct Coax Feed Add-On Kits )

The other point is to make sure you weather proof the coax and connections.  A number of years ago while on 75M running my L4B in the evening during a 6" snow event things suddenly stopped working.  Next day traced the problem to water inside the PL259 connection.  The center pin was nice and black and welded to the other end with the coax was shorted inside the PL259.  Wasn't as weather proof as I had thought.

I keep it as a reminder to weather proof, weather proof and weather proof.

73,

Carl - W9PMZ
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K0YQ
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Posts: 509




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« Reply #12 on: February 05, 2013, 11:10:00 AM »

Consider getting a flexible plastic trash can big enough to enclose the entire base and radial connection plate, cut a hole in it to fit upside down over the antenna base area, and use that to shelter the feed area.

Same idea but I just use a Rubbermaid office container, upside down, and drill a hole for the antenna to go through.  Keeps the pigtail and radial connections nice and dry all year.
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W8JX
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Posts: 6468




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« Reply #13 on: February 05, 2013, 12:18:18 PM »

Consider getting a flexible plastic trash can big enough to enclose the entire base and radial connection plate, cut a hole in it to fit upside down over the antenna base area, and use that to shelter the feed area.

Same idea but I just use a Rubbermaid office container, upside down, and drill a hole for the antenna to go through.  Keeps the pigtail and radial connections nice and dry all year.

This could be counter productive because is cannot breathe out excess moisture.
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N4NYY
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« Reply #14 on: February 05, 2013, 04:13:31 PM »

I never had a problem with mine. I used coaxseal on the feed. I would not worry about the ground radials and radial pad. If you are really concerned, then shove the area near the feed.
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