Hi Paul,
Thanks for the comments. Electrical storms, torrrential rain,
humidity, and relentless temperature cycling make Florida an unusually
hostile environment for antenna rotators, even for those purpose-built
for this application. Water ingress seems to be an inherent "difficult"
spot on vertical output shaft rotators. I'm on the Space Coast of FL
myself, so this is of particular interest to me as well.
M2 seems to have addressed prior output shaft water ingress problems in
their product several years ago with a significant redesign. So far,
I've found no info on the RT4500HD output shaft bearings and seals. DX
Engineering did release some informative 3D CAD drawings of the
internal drive components of the RT4500HD, but drawings of its output
shaft bearings and seals are conspicuously not among them. I did talk
to one of the DXE sales people, who was quite helpful in contacting the
rotator manufacturer who was willing to state that there are two buna-N
o-ring seals on the output shaft and an external rain shield of some
kind. Any observations or impressions you might have of your RT4500HD
in this area would therefore be most useful.
The RT4500HD has a particularly useful feature permitting easy
replacement of the magnetic reed switch in its positioning feedback
system without removal and disassembly of the rotator. Like the feedback
pots used in other rotators, these reed switches are easily destroyed by
direct or nearby lightning strikes which, unfortunately, are another
common and unavoidable problem here in FL.
Altogether, the RT4500HD appears to be well thought out, and a prototype
is said to have been subjected to extensive testing in the northeastern
Ohio environment. However, as the product is still quite new, it
appears few are in the field and no environmental reliability info is
yet available...
73,
John K9WT
On 7/22/2023 10:02 AM, Paul Christensen wrote:
I own a RT4500HD but waiting on cooler weather for installation. It seems robust enough
as it's replacing a small form-factor prop-pitch. Between excessive water leakage after
rebuilds and K7NV now SK, I was looking for an alternative. The reliability of
prop-pitch rebuilds has been disappointing. N4CC and I have been changing them out every
1-2 years at a cost of $2,500 per rebuild. Crazy. We have a prop-pitch
"graveyard" at our remote site with something like six prop-pitches needing
repair.
What seems to happen is that water ingress is caused by excessive surface heat
in the Florida summers, followed by cool rain. This creates a suck-in effect.
Because a prop-pitch is mounted upside-down in a tower, the seal needs better
protection without having to resort to a special covering. In this regard, the
DXE rotator seems much better. In fairness, the prop-pitch was designed for a
different application. But yes, only time will tell.
The first DXE rotator installation will turn a full-size 4L M2 40m monoband
Yagi at 140 ft and a 9L M2 6m Yagi at 155 ft. Both antennas are mounted on a
3-inch chromoly mast. This fits within the DXE design spec. In preparation
for the installation, we used a crane back in April to change out a Rohn 3-inch
thrust bearing with the equivalent type from DXE. The DXE bearing seems much
more robust.
Paul, W9AC
-----Original Message-----
From: TowerTalk <towertalk-bounces@contesting.com> On Behalf Of John Vendely
Sent: Saturday, July 22, 2023 9:33 AM
To: towertalk@contesting.com
Subject: [TowerTalk] DX Engineering RT4500HD rotator
Does anyone have any experience with or comments on the DX Engineering RT4500HD
antenna rotator? This new product appears to be a take-off on the M2 2800G2,
purportedly with some improvements, albeit at a significantly higher price.
Only time will tell, but I wondered if anyone actually owning one had any words
of wisdom for us.
73,
John K9WT
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