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Re: [TowerTalk] Need help with tower info

To: choelzle@cox.net, towertalk@contesting.com
Subject: Re: [TowerTalk] Need help with tower info
From: K7LXC--- via TowerTalk <towertalk@contesting.com>
Reply-to: K7LXC@aol.com
Date: Mon, 4 Apr 2016 10:26:16 -0400
List-post: <towertalk@contesting.com">mailto:towertalk@contesting.com>
>  Hello - I am intending on putting up a tower at my new  home in Bandon, 
Or. I
have 40 acres and it is surrounded with 70 foot high  timber. When I saw the
layout and I thought I would put up a 150ft tower. I  will not be doing this
often, so I want to put it up once and have it stand.  General TIA wind
ratings for the county are 80mph, with "special areas" - and  of course I am
in one of those special areas which has ratings of  110mph.
 
>  Right off the bat I excluded putting up a Rohn 25G, opting instead  for 
a 45G
- but then a buddy of mine said that he would go for a  55g.
 
>  I intend on putting up a big M2 or Mosley multi-bander  (15sqft) and a 40
meter three element (20 sqft).
 
>  I know of folks that have these sorts of setups, but  when I take a look 
at
the Rohn wind load I was really surprised.
 
>  A Rohn 45 150 foot 130mph rev G / 110 mph Rev F shows it  will only allow
10.4 sqft of load.
 
>  So, I thought a Rohn 55 would do the trick but it  shows:
 
>  Rohn 55 150 foot  130mph rev G / 110 mph Rev F shows  it will only allow 
16.6
sqft of load.
 
>  Are the specs WAY too conservative or should I put up a  really HUGE 
tower to
accommodate what I want to do?

Hiya, Chris  --
 
    You should get out like gangbusters since  you're close to saltwater.  
 
    First, you should read my UP THE TOWER book -  The Complete Guide To 
Tower Construction - available from many ham dealers  and will answer just 
about all of your questions including some you haven't  thought of yet. 
 
    In it you would find that in the General  Notes is a note that says 
that Rohn has deducted 8.0 square feet for  symmetrical mounts which is common 
in commercial applications. If you add the  8.0 sq.ft. back in, you'll see 
that you'll have significantly more tower  capacity. You're welcome. 
 
    Also, please DO NOT install a Mosley antenna.  In a landmark tribander 
on-the-air test that N0AX and I conducted, we found that  Mosley (Measly?) 
antennas under-perfom the competition. One model even had  negative gain on 
one band. The whole report is available from championradio.com  and will give 
you a complete picture of antenna performance. 
 
    I have a customer in Bandon - Dan Bissell,  W7WVF - you may know him. 
I'll be down there in the next few months to do some  work for him so maybe 
we can get together then. 
 
    I've worked on over 260 amateur and dozens of  commercial sites so have 
plenty of experience. 
 
    And congratulations for using TowerTalk. It's  saved many a newbie 
tower owner lots of grief thru the wealth of experience of  the members. 
 
Cheers,
Steve    K7LXC
TOWER TECH -
Professional tower services for amateurs
Cell: 206-890-4188

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