John.Evans@comsat.com wrote:
>
>
>
> ______________________________ Forward Header
> __________________________________
> Subject: Re[2]: HD rotators
> Author: John Evans at COR-FS5
To: <towertalk@contesting.com>
> Date: 1/6/97 3:57 PM
>
> Steve,
> My rotating tower system uses an HDR 300 rotator operating
> at half-speed through a chain drive. My particular "war
> stories" are that it would not hold the drive shaft provided
> by RTS, which is 2-inch in diameter. I had to get a collar
> welded on to increase the diameter to 3 inches to solve this
> particular problem. My other difficulty has been with the
> small screws that attach it to a mounting plate. Wind-induced
> vibration of some of the antenna elements couples into the
> tower and has twice caused these bolts to unscrew leaving the
> rotator hanging by its control cable! (The reason it happened
> twice is because I did not understand the cause the first
> time around!) When it happened the first time, the fiberboard
> cover was all smashed as well as the internal electronics. I
> had an aluminum box fabricated to replace the fiberboard one.
> This problem seems to have been solved by "Loctiting" the
> bolts into their sockets! Other problems include the control
> cable fouling the brake pall when first installed (resulting
> in the coax loop being shredded and the readout pot being
> smashed), and having to make harder keys. I am curious,
> however, to hear if you ever built someone a propitch rotator
> for this application? John N3HBX.
>
>
>
I have a HDR300 turning my RTS rotating tower and its worked fine for 4
or 5 years now. I don't think anyone has more antennas on theirs than
me, John. But I believe what you say. Just check out www.dunestar.com
to see the mess of aluminum I had on mine.
Anyway the shaft did turn in my hdr300 when I originally put it up.
Dick K5iu recommended I go to grade 8 bolts vs the HDR300 supplied ones.
Bingo no more problems. I think if it ever did turn again it would
probably save the rotor from destruction. So I want that.
I wonder if you must have some very unbalanced loads from your antennas.
I tried to keep mine in the exact centers of the booms to reduce torque.
I have not had a problem with the bolts backing out of the rotor plate
either. Dick supplied mine with huge bolts and split washers. I have
had the chain loosen up over the years. But it was easy to retighten by
moveing everything out in the slots provided for this purpose.
I think the HDR300 is fine for the RTS system. I did have CATS do a
total rebuild on my HDR300 before I put it into service. Well worth the
money to get the new gear assy. and the gold wx proof plug.
Just my $.02
Jay, WX0B
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