[TowerTalk] Mixing Rohn 20G and 25G

[Steve Maki]

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