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Subject: Re: [TowerTalk] WHICH ROTOR TO USE?
From: Per Molund <>
Date: Sun, 6 May 2012 01:11:00 +0200
List-post: <">>

I do not think it is quite fair to compare the largest PST with the small
CYtorq DX 1500. However, if You compare the PST with the DX Pro 4800 I
think You will find them quite comparable.

The CYtorq rotators have quite impressive data regarding accuracy and speed
and it is nice to see some advance in technology from the old 'dumb' DC
drive with potmeter as position sensor. Looking thru the documentation I
did not find any reference to wheter this is a open-loop system that can
get 'out of sync' and have to be recalibrated regularly (ref. SteppIR
antennas) or they have a closed-loop implementation with a position sensor.
Also there are no indication of the required number of conductors for the
rotator cable, since it involves a eight phase stepper I would guess 6
conductors for the stepper motor alone. From the picture of the controller
it looks like there is an 8 pin connector for the rotator.

I did not find any information on availability, I understand CYtorq have
been displayed on some ham shows? Hopefully it is not another 'shipping
next week' product, hint KX3 :-)

LA9XKA - Per

At 23:36 05.05.2012, K8RI wrote:

1500 in# of torque and 4500 in# of holding torque limit 25 sq ft of
antenna. It also has a 30' boom limit. My 7L 6-meter yagi would take
care of that.
It's not clear in the photos but I hope that is the top seal and not a
bearing where they show the rotator mounted to their 25G mounting plate.

  The PST-61D has 2,150 in# of torque and 16,530 in# of holding torque.
IE, it doesn't need a brake and is rated for 39 sq ft of antenna.
Weight 55#
IE about 43% more torque  2150-1500 = 650/1500=0.43 and almost 4X the
holding torque and 56% more antenna.

The heavy duty version PST61DHP has 7,640 in# of torque, the same 16,
530 in# of holding torque and is rated for 42 sq ft of antenna(s)Weight 66#
5X the rotating torque and 4X holding torque.

The early PST61s had a top seal problem that is supposed to have been fixed.
   Be wary of the older ones using the green, AC motor.  You can build a
shield to keep water off the top seal fairly easy, but they are likely
to fail if not modified.
I believe they also are using white Lithium grease now instead of the
heavy weight gear lube there were using.
One more point, I don't think you will get one inside a 25G.


Roger (K8RI)

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