[TowerTalk] Datasheet for Rohn TA-55

[Steve Maki]

I've mentioned this very point here in the (distant) past, when there 
were folks anguishing over whether they needed to reduce rotational 
torque on their tower. And others worried about shock loads on rotators. 
Maybe they do from an engineering standpoint...but noting that there are 
many 150'-200' heavily loaded 18" rotating towers still standing after 
many years can serve as a sanity check about needing star guys.

That said, tall 18" towers (without star guys) DO twist a lot. If you 
stand at the base of one during high winds and look straight up, you'll 
see yagis pointed every which way but south, simultaneously. That tends 
to be a good thing as far as shock loads on rotators - the tower itself 
acts as a shock absorber.

Not good though if you're trying to keep a high gain UHF yagi or dish on 
target.

-Steve K8LX

On 1/6/2017 12:32 PM, Jim Thomson wrote:

> ##  heres the part that I dont get.   The 6 point guy system will reduce on the tower
> where the..cue rack is installed... almost down to nothing.   Is torque even an issue ?
>
> ##  these rotating towers  all use rings..and the typ 3 guy wires per ring..are attached  to the
> ring.... not to the tower.   IE:   There is nothing to stop the tower from torquing at all !
> The guy wires on the rotating towers just hold up and support the tower, they dont provide
> any torque redux  at all.     Then folks install 188-220 ft tall rotating tower assys... with the
> usual myriad of large HF yagis on them, typ with a 80m yagi  at the very top.
>
> ##  meanwhile the rotor is at the very bottom, like on the K0XG setups.   The tower appears
> to me to be one big.... mother of all torque wrenches.  The myriad of yagis are all bolted to
> the same tower face too.  How much to these rotating towers actually twist in high winds ???
>
> ##  If twist is a non issue on a rotating tower, then why even mess with the ...cue-rack..aka
> rohn TA55  assy at all ??   What am I missing here ?
>
> Jim   VE7RF