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Author Topic: Butternut HF6V  (Read 1066 times)
W1JOP
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Posts: 21




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« on: December 20, 2008, 07:12:00 AM »

Hey,


 This may not be the best place for this but thought id give it a try.  I am looking into the Butternut HF6V HF antenna for my future upgrade, however I have a few quesitons about mounting recomedations at the antenna is 26ft tall, I live in a house wear I can ground mount the antenna and I cant penitrate the roof, roof mounting is the way to go but I am limited to the following

 Vent pipe mount-useing the  plumbers vent pipe to mount the antenna on a reltivly short mast


Chimeny mount, with a 10ft mast, antnna is designed not to be guyed however it i were to use saftey guys the vent pipe would be a better location for that.


anyone have any ideas of what would be best?


JP/W1JOP
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W3LK
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Posts: 5639




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« Reply #1 on: December 20, 2008, 08:32:19 AM »

See my response to your other posting.

The vent pipe is not a viable mounting for ANY antenna and the chimney isn't much better.

73,

Lon - W3LK
Naugatuck, Connecticut
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MAZZ1232002
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Posts: 205




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« Reply #2 on: December 20, 2008, 11:33:09 AM »

 I had a two meter 9 element yagi mounted to a chimney at one time and after several months I had to hire a brick mason to rebuild the chimney from the roof up. The chimney was 2 feet on a side by 4 feet high.
  Forget the vent pipe.

      Pete
      WB4CGA
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K0OD
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Posts: 2560




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« Reply #3 on: December 20, 2008, 12:58:40 PM »

When I was a kid I strapped a 3-element 20-meter beam to the chimney of my parents single story home. As I recall, I used just two straps.

It was a big chimney, perhaps 3' by 8' and about 6' tall.  Incredibly, nothing disastrous happened in the year or two the yagi was up. But Dad complained about roof leaks in that area for years afterward.

I cringe now to think of things I did when I was 16.
 
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WW5AA
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Posts: 2086




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« Reply #4 on: December 21, 2008, 05:23:50 AM »

Roof mount on a tri-pod.

73 de Lindy
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WB6BYU
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Posts: 13353




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« Reply #5 on: December 21, 2008, 06:25:18 AM »

I've seen commercially made mounts that straddle the peak of the roof
and hold cinder blocks to keep them in place, and I presume you could
make your own using angle iron.  You'll have to consider the tipping
and bending forces on the antenna (especially in the wind) but that would
be one option for mounting it on the roof without putting any holes
through it.

Most modern vent pipes are plastic and won't support the forces involved
with an antenna of any significant size.  The other problem is that, if
anything breaks in the system, you may end with sewage leaks in the
walls of house.
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W3LK
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Posts: 5639




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« Reply #6 on: December 21, 2008, 07:10:08 AM »

<< The other problem is that, if anything breaks in the system, you may end with sewage leaks in the walls of house.>>

The vents do not carry sewage, they vent sewer gas to the atmosphere. A cracked vent would vent the gas into the walls, not actual waste.

The vent system is at the TOP of the waste lines in a house. It would take a total blockage of the waste system in the house to force any waste into the vent system, and the sinks and toilets would back up and overflow first. I have never heard of actual waste in the vent system.

73,

Lon - W3LK
Naugatuck, Connecticut
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K0XU
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Posts: 294




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« Reply #7 on: December 21, 2008, 09:38:15 AM »

For many years I used a HB vertical with a mount INTO the vent pipe. I used galvanized pipe with a heavy galvanized angle u-bolted to it. Then the antenna mounted above the angle. I did use some guying to cut down on the noise of the thing banging around in the wind. This was a 20 meter quarter wave of aluminum tubing with parallel elements for 10, 12,15 & 17 meters. However the stuff coming out of the vent is damp and I needed to clean/redo the connections often. Be very sure of the u-bolt to the angle iron, if that fails you would have a mess.

BTW, the coax entry was through the rubber collar of the vent. Just bought and trimmed another collar to use above the original and ran the coax between the pipe & original collar. When I took it down all traces were removed. Might be a good trick for someone who was renting their home.

Jim
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W3LK
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Posts: 5639




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« Reply #8 on: December 21, 2008, 10:49:53 AM »

Jim, you were lucky!

That's a very bad way to mount an antenna.

<< Might be a good trick for someone who was renting their home. >>

If I were a landlord and found someone doing that, the rental contract would not be renewed.

73,

Lon - W3LK
Naugatuck, Connecticut
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A smoking section in a restaurant makes as much sense as a peeing section in a swimming pool.
KI5JB
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Posts: 2




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« Reply #9 on: December 23, 2008, 02:49:33 PM »

look up the Bencher site.go into Butternut then look up dirty little secrets.Study what Don has to say.He invented this antenna.73 Dan ki5jb
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WD8LIC
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Posts: 32


WWW

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« Reply #10 on: December 31, 2008, 04:42:38 AM »

My experience is the pressure from the wind, ice, etc. makes roof mounting not a good idea.  Ground mounting with 8 radials will preform very well and you can sleep nights, unless you are up working DX, and not have to worry about the damage to your roof, chimney, vents, etc.

Bob WD8LIC
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W3LK
Member

Posts: 5639




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« Reply #11 on: December 31, 2008, 03:46:15 PM »

<< Ground mounting with 8 radials will preform very well>>

With all due respect, eight radials is the bare minimum and "perform very well" is a nebulous phrase. A light bulb performs "very well" if one has nothing to compare it to.

Even if the eight radials were 1/4 wave on 80m, they would still be barely  adequate. 20-25 radials, 25' long is considered to be starting point for good performance.

73,

Lon - W3LK
Naugatuck, Connecticut
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KV9U
Member

Posts: 166




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« Reply #12 on: January 03, 2009, 03:08:42 PM »

I concur that 8 radials at least as long as the height of the vertical will perform well. Even four will do OK in many cases, but soil conductivity can make a difference.

I found that just over 30 radials would allow my Butternut to perform quite consistently better on 40 meters when compared to a low inverted vee dipole at about 35 feet apex height for longer distances. This is not a NVIS antenna however.

Since it is easy to add radials by just laying them on the soil surface, the best time to do this is in the spring before grass growth. In a few months the radials are not that exposed. In a few years you have to struggle to find them, HI.
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