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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