[Top] [All Lists]

Re: [TowerTalk] Antenna loads for rohn 45

Subject: Re: [TowerTalk] Antenna loads for rohn 45
From: jimlux <>
Date: Sun, 18 Jul 2010 15:58:03 -0700
List-post: <">> wrote:
> Apparently solid leg Rohn 45 does exist (model# 45GSR) and its windload 
> ratings are quite impressive - similar to Rohn 65G.
> John KK9A

But what's the cost comparison?  My gut feel is that 65G would be 
cheaper than 45G.  65 is also larger overall diameter than 45, which 
helps with the overall buckling load (you have to figure out the loads 
for the buckling of the little sub-tubes and the whole tower as a 
complete column)

off, I found this:
65G 1.9" OD tubes, .625" solid rod diagonal braces, 26.25" face width
45G 1.25" OD 9 tube (14 ga), 7/16" brace, 16.76" face width

So the question is, is a 1.25" solid member more cross sectional area 
(1.23 sq in) than a 1.9" tube (of some TBD wall thickness), and, more to 
the point, is its section moment comparable?   That 4th power adds up 
real fast.

Cost is probably pretty close to proportional to weight.

It kind of depends, too, on whether the limiting load is the buckling, 
or just straight compression.

(I guess that's why people pay Engineers to figure this stuff out)


TowerTalk mailing list

<Prev in Thread] Current Thread [Next in Thread>