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Re: [TowerTalk] Prosistel PST-61 or PST-2051 (a word of warning)

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Subject: Re: [TowerTalk] Prosistel PST-61 or PST-2051 (a word of warning)
From: "Kimo Chun" <>
Date: Mon, 7 May 2012 09:24:56 -1000
List-post: <">>
I agree with Andy.

We went through two Prosistel rotators. We got our money back on the third.
We went to prop pitch rotators with Green Heron controllers from Kurt, K7NV.


Agreed. In our case the rotator motor housing was connected to its base
housing with those 4 small machine srews, the base was made of cast aluminum
and they had no steel bushings on the bolts or special bolts with less
thread. In the near constant hammering the antenna (3 ele 40m yagi, full
size) put on the rotator in 5 - 25 mph daily trade winds the bolt threads
filed away the base housing holes until we had a nice pile of aluminum dust
between the base plate and the rotator shelf. We were alerted due to the
water ingress that then destroyed the position pot sticking out the bottom
of the motor housing, not to mention the increasing slop in the whole system
which eventually became visible from the ground.

With 1/2 inch or 5/8 inch bolts(?) (it has been a few years) holding the
base housing to the tower rotator plate, guess which bolts came loose first?
I am not a mechanical engineer but it looks like they could have changed the
location / design of their cast reinforcing ribs on the motor housing so
that half the holes (you can see are blanked out) that are not drilled or
useable to tie the motor housing to the base could be made useful. It
doesn't take an engineer to wonder why you would design 4 large bolts to the
shelf (good) then transfer that arrested torque to only four 1/4 inch bolts
into the motor housing. I suppose at least having a steel base housing may
have helped.

Yes, the motor assembly seems to be beefy enough but the physical
implementation through the base to the tower is poor. I had hoped it would
be redesigned by now (4 or 5 years later). Has it? We were fortunate that
the distributor stood behind his sale but when we spoke to the Prosistel
President in Dayton and presented our detailed analysis he essentially
brushed us off as "being a 2 percent problem" - Meaning you don't make major
manufacturing changes for problems that only affect 2 percent of your
customers. Okay, I suppose I can understand that but I can't see saying that
to the 2 percent to their face!

So, if you have the potential of the hammering that trade winds or
equivalent on a large antenna (within the specs of the rotator) can put on
the rotator don't take the chance you will be part of their 2 percent of
customers. We do have a motor assembly gathering dust on the shelf with at
least a bad pot and base (I don't know its true status).

There is absolutely no comparison between them and prop pitch motors. My
guess is that if an Orion is combined with a Green Heron controller that
would be another somewhat less durable choice.  We have used a number of old
Wilson WR-1000 (like T2X on steroids - running on 120VAC), M2 Orion - with
their digital controller (difficult to use), 3 Prosistel rotators and a T2x
on our 5 el 10M yagi. We have changed most to K7NV small prop pitches and
one medium on the 80m yagi. I think we still have the T2X but it is also
controlled by a Green Heron controller (none better). No problems anymore.

I apologize for getting on their case as we did get some satisfaction but
since someone else has broached the subject (and issue) I feel justified in
letting people know our experience and to exercise adequate caution in their
application or make another selection.



Kimo Chun, KH7U




Date: Mon, 7 May 2012 07:27:46 -0000

From: "Andy GD0TEP" <>

Subject: Re: [TowerTalk] Prosistel PST-61 or PST-2051 (a word of


To: <>

Message-ID: <00cc01cd2c22$e696b8c0$b3c42a40$@com>

Content-Type: text/plain;    charset="US-ASCII"


A word of warning about the PST61...


The PST61 looks man enough to turn most large antenna systems, BUT, that
large and strong look is let down by what you cant see...


The main body of the rotator is well built, and, in principle, would turn a
house :-) 


The main body is fastened (bolted) to the lower casting (that bolts to your

tower) using only FOUR 1/4 inch machine screw, yes.. that's not a typo...

1/4 inch machine screws. The casting has no other locating pins, or
interlocking castelations...  So, please have that in mind when you buy your
rotator for your large antenna system....


I have pictures of my PST61 once it had failed here: (and how i fixed it)


The control unit main transformer is (in my opinion) under rated if your
turning a large antenna... Where I am, the local contest group has 6
prosistel rotator, a mix of PST61, PST51 and PST2051, and we've had FOUR
transformer failures, after the first unit failed a second time, we pulled
the 100va transformer and fitted a 150va.


The prosistel design is a great idea, that in my opinion is poorly




Andy <> 





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