That's what we did (on a small scale) with our 4 high 10 meter stack of
4L yagis. The yagis at 40' & 60' rotate together and are treated as one
antenna in the stack switch. And likewise the pair at 80' & 100'.
300° of rotation is fine as long as you have at least one antenna that
can rotate the full 360°.
Our 20' masts are only 1-7/8" OD water pipe, which is perfectly adequate
for this little system. The thrust collars are short pieces of 2" ID
water pipe. I wouldn't hesitate to scale this up for larger antennas, up
to a point, depending on tower strength.
Everything is welded except for the antenna mast clamp. Very cheap to make.
Here's a couple shots:
https://app.box.com/s/fkft820hkiukr3ms4n909t16wz1d8hw3
-Steve K8LX
On 2/26/2020 11:49 PM, Grant Saviers wrote:
K0XG rings meet the bill, seven on my Rohn 65. Some startup fixesand
then no problems 5 years. see my QRZ page. A huge complex project though.
Would I do it again - no. I'd go with swing arms with 20ft masts,top
and bottom supports, 2 yagis per. It's rare I need fully independent
beams and almost never 360 degrees for me. I did the CAD work forthese
swing arms. Some CNC plasma cutting of 1/4" steel plate and welding
needed for a fraction of the cost. Uses a standard mount rotator,eg
Orion 2800, etc for rotation.
Grant KZ1W
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