On 9/3/2010 7:46 AM, Jim Thomson wrote:
> Date: Thu, 2 Sep 2010 20:10:38 +0200
> From: "DF3KV"<df3kv@t-online.de>
> Subject: Re: [TowerTalk] Antenna Rotor Speed
>
>
> I found 40 seconds for one rotation real nice for contesting after I built
> my own rotator.
I used the PST-61 to turn
http://www.rogerhalstead.com/ham_files/Tower29.htm which takes about 90
seconds per revolution, BUT as it has 520 degree rotation any particular
direction is usually no more than half a turn or 45seconds.
> I turned a christmas tree of 5 element yagis 20-10m + 3L FS on 40m without
> problems, but the stress on the double worm gearbox is quite heavy.
The PDT-61 uses a soft start and stop so there is no abrupt stress on
the gear train or antenna system.
73
Roger (K8RI)
> I used finally a 50mm drive shaft to flange to the rotating mast, 25mm
> sheared off immediately the first time the rotation stopped.
> On my present installation with slew ring drive it takes 90 seconds to
> travel 360? which I find a bit too slow.
> Higher speeds are no problem for antennas built to survive storms.
>
> 73
> Peter, DJ7WW
>
> ## PWM is cheap. I bought a small pre-assembled PWM on a PC
> board... and it's rated for a max of 30 Vdc @ 50 A CCS. The pot on
> the board is removed... and replaced with 1-3 pots..and a switch. Then you
> can switch from slo-med-fast.... and back down again.
>
> ## The GH box is superb.. with it's ramp up/down and point
> and shoot feature.
>
> later... Jim VE7RF
>
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