On 4/30/2011 2:00 AM, Jim W7RY wrote:
> Naw! The antenna just stop when it hits the tower. I know. I had one.
First the design is a very simple one, and like Jim I suggest the two
leg design. It is possible to exert a twisting motion on the side of the
tower if the all the bolts are not tight, or the system isn't aligned
correctly. That's not usually a problem, but a possibility.
At for the antenna hitting the tower
http://www.rogerhalstead.com/ham_files/tower36.htm this can happen
although it took years in this case. It was also under slightly
different circumstances, and quite close to the mast as you can see the
end of the boom to mast clamp.
OTOH IF and I emphasize the "IF" you have a lot of windy days AND the
antenna gets parked near the end of rotation, it is possible for it to
bang into the tower leg. There are just too many "IFs" to say if a
particular set up will cause damage or not. It generally takes
momentum/energy and a lot or repeats or rotating the antenna to the stop
on a 70 MPH plus windy day.
You could likely have the antenna up for years with no problem. Me? It'd
probably get busted the second week it was up. <:-(( I've literally
shattered Ham IVs, and messed up the insides of a pair of HDR 300s,
before i went to a PST-61, but the array was a tad larger than the 3L
SteppIR http://www.rogerhalstead.com/ham_files/Tower29.htm
> 73
> Jim W7RY
>
>
>
>> If the rotator OR antenna ever slips on the mast (and who hasn't seen
>> that happen) you are screwed. It might be worth putting
>> limit switches on the tower that contact the boom just
>> before a collision.
>>
>> Rick N6RK
>>
I don't think slipping on the mast would be much of a problem in this
case as directivity would *probably* be noticed as a problem before much
damage was done.
73
Roger (K8RI)
_______________________________________________
_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk
|