Steve The Dim for the two are the same except for the number of Z bars bays.
and the fact of the OD of the Z rung material and the wall thickness of the
vertical tubes , And yes this is Ham radio.... There are 1,000 of told and
many more untold stories of over loaded installation. Look at my 20-g to 25-G
install, I have 2 100 ft 25 G that I lay over falling deric style
But that was installed 25 years ago.... Now everything needs Engineering
drawings and meet a spec. and the truth a little search and for a few extra
$ the 20-G can be upgraded to 25-G and everything will be alright in this
litigating world .
Wayne W3EA
Ps If my mix 35 ft tower were not house bracketed @ 18 ' I would have not
used the 20-G
> Date: Tue, 1 Jul 2014 21:03:37 -0400
> From: lists@oakcom.org
> To: towertalk@contesting.com
> Subject: Re: [TowerTalk] Mixing Rohn 20G and 25G
>
> On 7/1/2014 8:03 PM, Roger (K8RI) on TT wrote:
>
> > Remember, 20G is only rated for 2 sq ft of wind load...IE a TV antenna.
> > They, like many ham installations with other towers have supported much
> > more than their ratings, but you are far past the ratings and who knows
> > how close to the ultimate load and at what wind.
> >
> > I'd not mix them, nor put mote than a 2-meter yagi, or a light weight 3L
> > 6-meter if it's close to 2 sq ft. and then only if I was willing to
> > sacrifice the antenna and it wouldn't hit something expensive or
> > electrical.
>
> Before we go completely off the rails, it might be helpful to compare
> the weights of the sections, since they are of similar dimensions. Rohn
> 25 is around 3.5 lbs/ ft, and Rohn 20 is around 3.0 lbs/ft as I recall.
>
> To me this doesn't immediately indicate that 25 is many times stronger
> than 20. Even if 20 has slightly less leg wall thickness, and slightly
> less material in the Z bracing - I'm sure 60' of 20 with a couple bays
> of reasonable guys will hold a tribander. Cone on....this is ham radio.
>
> -Steve K8LX
>
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