Hello,
We live on a very windy Island (with an industrial wind farm) and have been
loosing shingles off the roof due to severe wind storms.
We've been considering having a metal roof, but I'm wondering about the
possible impact of the metal roof on the radiation pattern and efficacy of
nearby ant
On another angle, I have a 2-element vertical array [Christman feed,
BIP-BOP]
for 40m sitting on topof a [large] flat metal roof.
It works FB, perhaps in part because the steel roof provides a
nearly-perfect ground plane ??
Eric VA7DZ
--
"We have the best model of learning that
17th-century te
Paul,
Our home is about 25 miles east of downtown Sacramento, CA. It is a two story
home and until May of 2012 had a wood shake roof - very common in this part of
the state. It was the original roof, about 21 years old, and was getting pretty
nasty. We had it replaced with a metal roof: the "Ba
ground plane. Worked great.
Mel, K6KBE
From: Jim Bennett
To: Paul Taenzer
Cc: elecraft@mailman.qth.net
Sent: Thursday, July 4, 2013 10:31 AM
Subject: Re: [Elecraft] OT - anyone have experience with effects of metal roofs
on antenna performace?
Paul,
Our
Yes. Yes I was. :-)
On Thursday, Jul 4, 2013, at Thursday, 12:11 PM, Tom H Childers wrote:
>
> You must have been running very low power. Laying any kind of
> ladder-line on a roof, insulated or not, is an excellent way to have
> a house fire that the insurance company will not pay for. Espe
I didn't see the original reply, but I just wanted to clear up one
misconception. Homeowner's insurance covers stupidity. Unless it can be
proved that you put that ladder line on the roof and ran high power
through it with the intention of burning the house down, you would be
covered.
73,
Joh
Not sure I'm liking where this conversation is going. I answered the original
poster's question as to whether a metal roof has been seen to adversely affect
antenna performance, not advocate doing "stupid" things. My installation worked
very well for me w/o running high power. I knew I WOULD be
I run an Optibeam OB9-5 at about 42 feet on a tower only 10 feet away
from the corner of our single story house with metal roof.
It hasn't disadvantaged me any. I see a small change in SWR as the
larger elements of 20M and 17M swing over the roof.
Regards,
Mike VP8NO
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> CC: elecraft@mailman.qth.net
> Subject: Re: [Elecraft] OT - anyone have experience with effects of metal
> roofs on antenna performace?
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I ran some quick models of a tower at the corner of a house with
a metal roof in HFTA. The effects of the metal roof were modeled
by a plane (sloping) from the tower to the edge of the roof, a drop
from eave height to local ground height (set to flat for these
purposes) and then flat ground out
On Thursday Taenzer used a Straight-Key to send:
-Original Comment---
> We've been considering having a metal roof, but I'm wondering about the
> possible impact of the metal roof on the radiation pattern
I can tell you that my barn metal roof allows me to make about an hour
wind
Have used metal as a ground plane & it worked great. Metal sections must be
well bonded together or rectification will result. The larger the better.
John Hendricks K7JLT
On Jul 4, 2013, at 16:16, KD7YZ Bob wrote:
>
> On Thursday Taenzer used a Straight-Key to send:
> -Original C
Sorry, that was not my intention. We all do "stupid" things. The
intention of my post was not to say that what you did was stupid. My
illustration particularly mentioned running high power, which you
already said you had not done, as an extreme to illustrate the point.
Insurance won't cover it
I had verticals on concrete, roof shingle and metal roofs. Always radials
lying on top. The metal roof was the best by far.
One way to find out how much the roof is affecting the performance of a beam
is to look at SWR changes as the antenna is rotating.
Ignacy, NO9E
--
View this message in
SWR is a pretty coarse indication of interaction. Interactions can
change directional antenna F/B and F/S ratio by 6-10 db easily (assuming
you have it in the first place) and hardly affect SWR.
At least, this is my experience from antenna modeling.
However, we have to live with the hands we'
I remember the toughest class was antenna theory. As an undergrad EE student,
I believed that this class would kill my plan to be an EE. I got a 25 (out of
100)! No bragging, it was the highest grade. They graded on a curve. My prof
was a world renown antenna expert. He liked to &@#* with u
On 2013-07-05 22:22, Brian Alsop wrote:
SWR is a pretty coarse indication of interaction. Interactions can
change directional antenna F/B and F/S ratio by 6-10 db easily (assuming
you have it in the first place) and hardly affect SWR.
At least, this is my experience from antenna modeling.
Howe
A 4 square can be badly affected by metal (towers, masts, metal roofs). The
gain is similar but it loses front to back ratio in the affected direction.
David
G3UNA
You forgot the Gain. Forexample you can loose 2 - 3 dB gain on an
antenna due to interaction with another antenna or "object" a
ce on the radio and in eyeball QSOs.
Willis 'Cookie' Cooke
K5EWJ & Trustee N5BPS, USS Cavalla, USS Stewart
From: Paul Taenzer
To: elecraft@mailman.qth.net
Sent: Thursday, July 4, 2013 11:19 AM
Subject: [Elecraft] OT - anyone have experience wi
x27; Cooke
K5EWJ & Trustee N5BPS, USS Cavalla, USS Stewart
From: Jim Bennett
To: Elecraft Reflector Reflector
Sent: Thursday, July 4, 2013 3:54 PM
Subject: Re: [Elecraft] OT - anyone have experience with effects of metal roofs
on antenna performace?
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