Is there a significant difference between guying and bracketing a tower?
I'd expect them to behave about the same, but maybe house bracketing is
more rigid since guys are springy.
Alternatively, I hear that for short (~100 foot or less) 25G towers,
1/4" EHS can be used instead of 3/16" EHS for a more rigid tower without
putting too much weight on the legs. If flex is an issue, maybe that's
the way to go? Although if leg weight loading is a concern, I guess I
should work out how much downforce a 20G section can support, since
it'll be less than 25G.
--Nathan
On 07/01/2014 10:32 PM, Wayne Kline wrote:
Two levels of guy is what my concern would be. I am in as now and be home in PA
next week.
I have a library or Rohn catalogs and in the older ones I have the full spec on
r 25 -G.
But if my gray matter serves me well R 25- Gg is not suitable for guying let
alone two levels .
And this was the old spec. So with out a house bracket your walking on thin ice.
YMMV
Wayne W3EA
Sent from my iPad
On Jul 1, 2014, at 6:24 PM, "Linux Mercedes" <linuxmercedes@gmail.com> wrote:
Wayne,
I'll primarily be using it for wireless internet. Unfortunately, the tech at
the WISP I spoke to was pretty vague about the wind load of the antenna they'll
be using, but he assured me it would be 'minimal' and didn't think it would be
that big of a concern.
I won't be house bracketing this install, but it will be guyed at two levels
(what Rohn recommends for 50' of 25G).
--Nathan
On 07/01/2014 09:59 AM, Wayne Kline wrote:
I also have experience with 20-G and 25-G towers... @ my station my 2mter/450
MHZ and one 6 meter beam
5 element 14' boom are on at 36ft. an consist of 3 sections of 20-G and a
top of 25-G AG3 ? it's house bracketed @ 18 ft.
Been in place for 24 years BUT extremely light wind load.
IMHO @ HF a C-3. TA33 or A3 would be the BIGGEST .
So my question to you is WHAT are you planning to adorn the tower with ?
Wayne W3EA . .
Date: Tue, 1 Jul 2014 07:42:14 -0500
From: kkbroadcastengineering@gmail.com
CC: towertalk@contesting.com
Subject: Re: [TowerTalk] Mixing Rohn 20G and 25G
Nathan,
I would caution you to not mix the sections nor even use the 20 for
anything more than VERY light duty use.
With that said... Back in my younger days when I did a lot of tower work
for CB and Ham operators, there were a number of mixed 20/25 towers
supporting large CB antennas and they stayed up many years. I do recall
working on one where the 20 top section physically broke during a wind
storm.
Climbing a mixed 20/25 tower is a real pain as the steps are different
distances apart.
Good luck,
Kevin C. Kidd, CSRE/AMD
AM Ground Systems Company - WD4RAT
kkidd@kkbc.com -- 866-22-RADIO -- 866-227-2346
www.amgroundsystems.com
On Mon, Jun 30, 2014 at 7:42 PM, Linux Mercedes <linuxmercedes@gmail.com>
wrote:
Hello,
Whilst moving tower sections from the shed to the shop so I could clean
them up and make a couple of fixes before putting up my tower, I noticed
that some of them seemed lighter than others. Turns out I've got a mix of
20G and 25G sections.
What are your thoughts on putting up, say, 30 or 40 feet of 25G and then
another 20 or 10 feet of 20G? I'd like to use the best sections I have on
the tower, but if mixing is a no, then I'll fix up some of the other
sections I have and build a homogeneous tower.
Thanks,
Nathan
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