[TowerTalk] DX Engineering RT4500HD rotator

[John Vendely]

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 at contesting.com> On Behalf Of John Vendely
> Sent: Saturday, July 22, 2023 9:33 AM
> To: towertalk at 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
>
>
> _______________________________________________
>
>
>
> _______________________________________________
> TowerTalk mailing list
> TowerTalk at contesting.com
> http://lists.contesting.com/mailman/listinfo/towertalk
>
>
> _______________________________________________
>
>
>
> _______________________________________________
> TowerTalk mailing list
> TowerTalk at contesting.com
> http://lists.contesting.com/mailman/listinfo/towertalk