[TowerTalk] Rohn 25 & Mast lingth

[john at kk9a.com]

There are many factors involved and I do not know anyone who has done this
calculation. Personally I use 1/3 in the tower and 2/3 out however that is
based on no structural knowledge. Rohn 25 is not that strong so it does
not make sense to use the super 4130 20+ foot DX Engineering mast that was
mentioned in a previous post.


To:	towertalk at contesting.com
Subject:	Re: [TowerTalk] Rohn 25 & Mast lingth
From:	Jim Brown <jim at audiosystemsgroup.com>
Reply-to:	jim at audiosystemsgroup.com
Date:	Tue, 18 Apr 2017 10:21:18 -0700


I'm not a structural or mechanical engineer, but from my courses at the
beginner level in those disciplines 50+ years ago, it seems to me that how
much mast is needed within the tower depends on what is above the tower on
that mast, how long that mast is, and the wind loads.

If you're an ME and have done the calcs, I'll certainly defer to your advice.

73, Jim K9YC

On Mon,4/17/2017 2:26 PM, Grant Saviers wrote:
There is no structural advantage to more mast inside the tower beyond 3 ft
or so. More doesn't matter either way.