We have installed a number of the RT4500HD and OR2800 rotators, all in Rohn 45
or 55 towers.
The bolt patterns are the same, though the RT4500HD uses four 5/16-18 bolts for
the base mounting and the OR2800 uses six 3/8-24 bolts. (I have one older
OR2800 here that used four 5/16" bolts).
On the first RT4500HD we installed about three years ago, the K7NV-style clamps
were not available and we used a clamp from an OR2800. They fit together fine
without modification. This was on a new galvanized 3" chromemolly mast and
there has not been any slippage reported. With the OR2800 clamps slippage seems
to be more of an issue with 2" steel masts.
Setup of the RT-21 with the RT4500HD was identical to that of the OR2800 in the
appendix of the RT21 manual. The 4500 has no physical stops though, while the
OR2800 does.
The RT4500HD is lighter -- 22lbs vs 42 for the OR2800.
The RT4500HD should not be lifted by the top plate -- it is held on to the
shaft by a single circlip. DXE ships the rotator with a bar across the base
bolts to use for lifting.
We have never had any fit issues with new or old galvanized 2" or 3" masts
sliding into the K7NV style clamps.
DXE also has their "Super Duty" mast clamps which provide a firm grip on the
mast, available in three different mast sizes: DX Engineering DXE-SDMC-2HD DX
Engineering Rotator Super Duty Mast Clamps | DX Engineering
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DX Engineering DXE-SDMC-2HD DX Engineering Rotator Super Duty Mast Clamp...
Free Shipping - DX Engineering Rotator Super Duty Mast Clamps with qualifying
orders of $99. Shop Rotator Unit M...
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73/Jon
Jon P. Zaimes, AA1K
Tower climber for hire
Felton, Delaware
http://www.aa1k.us/
Cell: 302-632-2353
Reviews of AA1K tower work on eham website:
http://www.eham.net/reviews/detail/12922
Hug your favorite tower every day, and always stay connected to it.
On Saturday, November 8, 2025 at 12:08:24 AM EST, Riki, K7NJ via TowerTalk
<towertalk@contesting.com> wrote:
I'm considering replacing my ancient AC version Orion OR2800 with a DX
Engineering DXE-RT4500HD. If I do this, I would hope that mechanically, it
would be a drop-in replacement. I would be very grateful to receive replies
from anyone who has replaced an Orion 2800 with a DXE rotator in a Tashjian
LM-470 crankup tower. In particular, I would like to know:
1. Is it possible to fit the DXE rotator through the opening in the
top of theLM-470 tower?
2. Is the bolt pattern on the bottom of the DXE rotator the same as on
the Orion 2800?
3. Will the Orion's mast clamps properly mount on the DXE rotator top
plate?
4. Comparing the specs, the DXE rotator is 9.205" from base to top of
mast platform, and the OR2800 is 9.75*. Since I'm not able to conveniently
measure this, I would like to know if these numbers appear to be correct(?).
I would be using a Green Heron RT-21 controller. It seems that many are
using this with the DXE rotator. I've not yet found the recommended set-up
instructions for the Green Heron when used with the DXE rotator. Guidance
on this would be appreciated.
Any other information would be appreciated.
Thanks for your input !
73 de Riki K7NJ
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