[TowerTalk] Mixing Rohn 20G and 25G

[Wayne Kline]

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 at oakcom.org
> To: towertalk at 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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