Mine is the earlier version with the AC motor. I don't know if the
mechanical part of the new version has addressed the faults listed below
or not.
I was using a PST61 on the array shown.
http://www.rogerhalstead.com/ham_files/Tower29.htm . It worked fine
except for the top seal design captured water causing the output shaft
to rust which destroyed the seal letting water into the rotator. A
friend turned down the output shaft to get rid of the rust pits, so a
slightly overs size seal worked just fine. That too is shown in the
rebuilding link.
Beside the top seal design which can be worked around, I was made aware
of the rotators main weakness being the bottom attachment to the mount
being only 4 bolts shown in photo 21 in
http://www.rogerhalstead.com/Gears.htm Everything in the rotator is
heavy duty (as shown in the rebuilding photos), "except" for those 4
bolts. I had no problems, but some others have had serious problems
with large antennas.
The rotator is rated for 44 sq ft of antenna wind area, but I have my
doubts as to those 4 bolts in that mount.
I like the way the PST61 works, but it does have a few short comings.
OTOH, I think I'd go with the Alphaspid, or possibly the big (I think
it's the PST71) for the large antenna.
73 es good luck!
Roger (K8RI)
On 4/25/2016 Monday 3:14 PM, john@kk9a.com wrote:
Nice antenna! I'm a big fan of prop pitch rotators.
John KK9A
To: towertalk@contesting.com
Subject: [TowerTalk] Rotator Choice for Larger Yagi
From: Jerry Gardner <jerryw6uv@gmail.com>
Date: Mon, 25 Apr 2016 11:00:22 -0700
Hi Tower Talkers
I'm planning to replace the TH-7DX on my tower with an Optibeam OB17-4,
which is a much larger antenna. I'm now looking at my options with regard
to rotators beefy enough to handle this antenna (~27 sq. ft. wind area).
Which of these would be sufficient to handle an OB17-4? Alfaspid RAK (the
rotator currently on the tower), an Alfaspid Big RAK, or a Prosistel PST61.
I don't need a controller as I already have a Green Heron RT-21.
Thanks,
Jerry
_______________________________________________
_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk
--
73
Roger (K8RI)
---
This email has been checked for viruses by Avast antivirus software.
https://www.avast.com/antivirus
_______________________________________________
_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk
|