[TowerTalk] Replacing Orion 2800 rotator with DXE-RT4500HD

[Richard (Rick) Karlquist]

On 11/8/2025 6:14 AM, john at kk9a.com wrote:
> I have no experience with the Orion or DX Engineering rotator but I would
> recommend using the K7NV style mast clamp with the DXE rotator.  It is a
> great design maximizing the contact surface area.  I have never had a K7NV
> clamp slip, even with 60ft boom HF antennas.

An alternate view of the K7NV clamp from another owner of one.
I have a big problem with "maximizing the contact surface area".
First, coefficient of friction is independent of area.
Second, the effective contact area of this clamp is highly
dependent on small variations in the mast diameter and eccentricity.  It 
turns out that the mast with 2.000 inch diameter might fit the K7NV
clamp like a glove, but if the same mast is galvanized, the thickness
of the galvanizing can cause the mast to have a large effect on the
behavior of the clamp.  The galvanized mast may not even be able to
be inserted into the clamp.  In conclusion, the K7NV clamp is no 
panacea, although it is certainly superior to the Orion clamp.

73,
Rick N6RK