Tnx Grant, My repeater is desensed....Folks from 30 to 40 miles are not
heard.... Xmit seems ok but the pattern is off.... The tower is on the East
side of the house...
the xmit favors the East side as if reflects off the roof......
I've done some experimenting with my moble HF rig.... I must be over 100ft from
the house to have (what seems like reflection) over 200 ft best on the swam
part
of my property....I would like to keep at least 200 ft between towers....I have
no trees on 16 acres flat land with 190 deg + view.....
I also have an 80 meter four square to install.....I'm getting interested in
contesting again at 70, I do get tired... I'll have 3 stations setup
when its ready.... tnx de Skip K3CC
-----Original Message-----
From: Grant Saviers <grants2@pacbell.net>
To: Gilbert Kauffmann <k3cc@verizon.net>; towertalk <towertalk@contesting.com>
Sent: Thu, Jan 11, 2018 9:26 am
Subject: Re: [TowerTalk] Metal Roof
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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