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Re: [TowerTalk] Metal Roof

To: Gilbert Kauffmann <k3cc@verizon.net>, towertalk@contesting.com
Subject: Re: [TowerTalk] Metal Roof
From: Grant Saviers <grants2@pacbell.net>
Date: Thu, 11 Jan 2018 09:26:59 -0800
List-post: <mailto:towertalk@contesting.com>
What does "interferes with the 2 meter repeater" mean?

We could get in the ballpark SWR curves to prove an A4S tribander was assembled correctly for FD at about 60' out and 42' up from a 56 x 70 x 14' all metal building. That doesn't say much about the pattern, 'tho. I think a couple of wavelengths is a good goal. My 40m Moxon seems to perform as modeled F/B at 91' up and 70' out from the same building, SWR is perfect to modeling. A 4L SteppIR at 40' out and 91' up from same building works very well (F/B, swr) 20 > 6m.

A 40' 3" irrigation pipe 80m top loaded vertical I had on a galvanized metal barn roof peak was awesome at 1550' above a prior Silicon Valley QTH. Wind to 80mph. Something you might consider for 80/160.

It is possible to model large conducting plates near antennas or as ground planes, but it is a lot of work and requires NEC4 IMO.

Grant KZ1W


on 1/11/2018 8:19 AM, Gilbert Kauffmann wrote:
I live on top of Niles Hill  about 2,300 ASL  and the winds is unbelievable 
high...
I lost part of my shingle roof twice and the insurance company dropped me.....
Now, I have a metal roof, fantastic, no problem with 60 mph winds.....

However, I have a 40 ft tower with a 2 meter repeater antenna.....It seems that 
the metal
roof interferes with the 2 meter repeater....  Also, my 160 meter OCF pattern 
has changed
a bit toward Northeast....
As a summer project I have help to erect 2 towers  40 and 50 ft,  If more time 
89 ft Self support....
antennas,  M2 3 el 40 yagi....Mosley TA34XL,......2 stacked 105CAS....M2 6M7JHC

Does anyone know how to figure how far the towers should be away from the house 
?? It seems
the metal roof  80 ft long has some interference of 2 meter and my  OCF 
dipole....

Tnx  de Skip  K3CC
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