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Old September 23rd 05, 07:38 PM
Rod Maupin
 
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Default Metal Roof and Vertical Antenna

I posted this on the wrong newsgroup a few days ago and no one has answered,
so I'll try here.

I have a Butternut Vertical (as a secondary antenna) and a regular radial
system set up with it. I also have a metal roof on my house (here in the
country in Western Washington). I have been wondering if I can use the
metal roof as the radial system/ground plane for this antenna. Haven't
tried it yet. Would this work or would it detune the antenna?

What do you guys think?

Rod KI7CQ


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Old September 23rd 05, 08:15 PM
Richard Clark
 
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On Fri, 23 Sep 2005 11:38:03 -0700, "Rod Maupin"
wrote:

Would this work or would it detune the antenna?


Hi Rod,

It would be simpler to just do it and see what happens. The worst
that comes of it is that the metal roof needs the sections
electrically bonded together. Not so much as a "ground plane" as to
reduce corroded connections (by bridging and shorting them) that act
as semiconductors and thus give rise to spurious emissions.

Any elevation removes your antenna from the deadly embrace of lossy
ground.

73's
Richard Clark, KB7QHC (also Western WA, Seattle)
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Old September 23rd 05, 08:36 PM
Rod Maupin
 
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I think you are right, Richard. I'll just do it and see what happens. The
thing is the roof is a painted metal, so I'm curious if there is continuity
between the sections.

Thanks Richard. By the way, I live in Rainier, down by Olympia.

Rod


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Old September 23rd 05, 08:58 PM
 
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I have a Butternut Vertical (as a secondary antenna) and a regular radial
system set up with it. I also have a metal roof on my house (here in the
country in Western Washington). I have been wondering if I can use the
metal roof as the radial system/ground plane for this antenna. Haven't
tried it yet. Would this work or would it detune the antenna?


I did that once with a HF6V and a metal roof about 40' above ground.
It seemed to work fairly well. The tuning on the Butternut is fairly
touchy on several bands, so yes, you will probably need to retune it
between roof mounting or ground mounting (I did).

Tor
N4OGW

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Old September 23rd 05, 09:10 PM
Rod Maupin
 
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Thanks Tor. I have the same antenna, an HF6V. You're right. It is touchy
on some of the bands.

Rod




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Old September 23rd 05, 09:11 PM
David G. Nagel
 
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Rod Maupin wrote:

I think you are right, Richard. I'll just do it and see what happens. The
thing is the roof is a painted metal, so I'm curious if there is continuity
between the sections.

Thanks Richard. By the way, I live in Rainier, down by Olympia.

Rod


Rod;

Assume not and you will not make an Ass of you and me.
Bond the individual segments and let us know how it works.

Dave WD9BDZ
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Old September 24th 05, 03:26 AM
Gene Rodgers
 
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Try an antenna tuner to balance it out.

gene

"Rod Maupin" wrote in message
...
Thanks Tor. I have the same antenna, an HF6V. You're right. It is
touchy on some of the bands.

Rod




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Old September 25th 05, 03:42 AM
 
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It will work, but you have to treat the roof as a psuedo
mobile setup, as it's not resonant. Well... Unless you
get lucky.
I'd just ohm out the roof and see if it's connected before
I started trying to bond it together.
The performance is semi iffy...
In general, radials that are resonant would be better, but
that assumes there are enough of them for a given height.
It's quite possible some bands may be fairly poor, if the
roof shows a high impedance. IE: much like trying to
use 1/2 wave long radials elevated...
MK

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Old September 25th 05, 04:38 AM
H. Adam Stevens, NQ5H
 
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I have a Fluidmotion BiggIR on a 3500 sq ft peaked aluminum roof.
Feedpoint impedance near 50 ohms at resonance can be achieved in such a
configuration.
73
H.
NQ5H

wrote in message
ups.com...
It will work, but you have to treat the roof as a psuedo
mobile setup, as it's not resonant. Well... Unless you
get lucky.
I'd just ohm out the roof and see if it's connected before
I started trying to bond it together.
The performance is semi iffy...
In general, radials that are resonant would be better, but
that assumes there are enough of them for a given height.
It's quite possible some bands may be fairly poor, if the
roof shows a high impedance. IE: much like trying to
use 1/2 wave long radials elevated...
MK



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Old September 29th 05, 06:44 PM
Dick, AA5VU
 
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In article ,
"Rod Maupin" wrote:

I posted this on the wrong newsgroup a few days ago and no one has answered,
so I'll try here.

I have a Butternut Vertical (as a secondary antenna) and a regular radial
system set up with it. I also have a metal roof on my house (here in the
country in Western Washington). I have been wondering if I can use the
metal roof as the radial system/ground plane for this antenna. Haven't
tried it yet. Would this work or would it detune the antenna?

What do you guys think?

Rod KI7CQ


Rod,

Several years ago I tried a 14AVQ vert next to the house with a big
jumper to the tin roof. Boy was that a mistake! It did not work at
all. I gave up on the vert and installed a tower and beam.

FYI, the best improvement ever made to the beam was when we replaced
the tin roof with normal singles. It was like getting a new antenna too.

Good luck with the tin roof. BTW, it did work pretty good with a mag
mount VHF/UHF antenna. HiHi

Dick AA5VU
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