Rotators for EME arrays

The following discussion about the rotators for EME arrays took place in the Moon-Net reflector. I found the subject so interesting that I decided to put together all the messages in this page.

On 13-April-1999 AL7EB wrote:
Well, I rewired the two antennas (M2 xpol-20's) after work and installed the M2 4-way divider (with 50 ohm loads on two ports) in place of the RG-11 matching lines.  Perfect match!  So I ran the antennas up to the top of the tower and swung them around toward Anchorage (98 km) for the Monday night SSB net and promply got the rotator stuck.  Arggh!  It didn't want to pass south and I shouldn't have forced it now it won't come back so I can't get back to the stow position for lowering.  Arggh!@#$&*!  Looks like I will be getting a new rotator sooner  (already knew it wouldn't turn 360 degrees...noe it has decided not to turn 180 degrees).  Will have to climb tower and unbolt the rotator clamp and manually turn it to the stow
position (north).  I knew that used Ham-III was too light (hmm...wonder how far I can throw it).

What I really wrote about was for an opinion on new rotators:  looking at the Yaesu G-1000SDX vs. Hy-gain T2X.  both are rated for 20-22 sq ft, 79-83 ft-lbs torque, $479-488.  My antennas will total approx. 17 sq-ft and a K-factor* of 1100 ft-lbs.
Note: K-factor=turning radius x weight.  The K-factor for the G-1000SDX is 2020 ft-lbs.  T2X=?

Is either one easier to computer control?  I'm not going to buy the manufacturers expensive interface.  How about backlash, pointing accuracy?
Since I'm going to spend money, I want to get the right item.

 What's your opinion?

On 13-April-1999 GM4JJJ wrote:
I recommend the CREATE RC5B range (made in Japan) They have worm drive and really good strong chunky metal gear trains. Backlash is very low compared to others and they don't slip in high winds, don't need a brake because of the worm drive. Good accuracy too, with a round controller. Variable speed control and also reversal delay.

I have not seen a Yaesu/Kenpro/Hygain/Emoto model that is anywhere as well engineered.

Another one to look at is the M^2 Orion - again a worm drive I believe.

One further comment, always buy a BIGGER rotator than you think you need, it pays dividends. I bought 3 before I got the right one!

Also consider if you can get spare parts easily in a few years time, I have been caught out that way with Emoto who had no spares a few years down the line.

http://www.elecdist.com/create/rotors.html for details of the Create Range of sturdy rotators.

On 13-April-1999 K0GU wrote:
I have a RC5B3. It's a nice rotator but costs over $1K US these days.I also have a Orion OR-2800 which appears to be a much more heavy duty rotator than the RC5B3 for near the same amount of $$. But I really like the Create control box. Much nicer for day to day operation with the preset control. For EME the Orion has the computer interface that can
be used to control the array for tracking the moon.

I'm not sure what the RC5A series costs these days.

> > What I really wrote about was for an opinion on new rotators:  looking at
> > the Yaesu G-1000SDX vs. Hy-gain T2X.  both are rated for 20-22 sq ft, 79-83
> > ft-lbs torque, $479-488.  My antennas will total approx. 17 sq-ft and a
> > K-factor* of 1100 ft-lbs.

If you put 20 sq feet on a G-1000SDX here in windy Colorado itlikely won't last too long. But it might be OK for your array. The T2X?? I hate wedge brakes, I hate wedge brakes, I hate wedge brakes. In windy CO sometimes the wind is pushing against the wedge and it won't release. Or you turn the antenna all the way to the stop and the wedge gets stuck and you have to climb the tower and unstick it. Did I mention I hate wedge brakes??

My personal comments that you really didn't ask for. I have never sold a rotator in 28 years as a ham. It's the one thing you always need. Figure out what size you need from the manufactures specs then buy the next biggest one (or bigger if you can afford it). Save yourself the grief later. Most of the rotators on the market will not live up to their specs in severe conditions.

On 13-April-1999 GM4JJJ wrote:
> I'm not sure what the RC5A series costs these days.

Its a little cheaper I think about $800, in fact I use an RC5A-3 for my array. The RC5B3 is about $1300.

You may find it cheaper to import your Create from Japan yourself.

I also agree about avoiding Wedge brakes. I had one in an Emoto rotator and that was a pain. Even with the brake the Emoto gear train stripped and I couldn't get spare parts for it.

On 13-April-1999 AL7EB wrote:
Thanks for the replies!
David Anderson GM4JJJ, Jay K0GU, Keith G4FUF, Niklas SM7UFW, Lance Collister W7GJ, and Lionel VE7BQH came back with good advise.  The gist of which was either the Create or Orion rotators.  Well, Mike, K6MYC asked what I was planning on using when I ordered the antennas...probably knew the ham-3 wouldn't make it, but was kind.  The big rotators are out of my reach; have already spent $4K on the antennas, etc, and still have an amp to build.  Probably go with the Create RC5A-3 ($750 from HRO). Unfortunatley, there is a 3-4 week delay on delivery.  I hope it fits on the stock Hazer bracket, otherwise I'll have to take everything down.  Good news, is I've already had an offer for the old ham-3 (I think).


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