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If you're stacking the 91XGs horizontally, you can't use a metal cross-boom between the antennas - you have to use something like a fibreglass cross-boom. The metal cross-boom will impact the designed behaviour of the antennas, likely adversely.
 

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Thanks. I've been using/experimenting with stacks for a long time,using AL crossbooms with a 10-12 inch riser on the ends and decided to push the envelope to reduce the mast windload. I experimented quite a bit this last Fall with different configurations.The best seemed to be two vertical rows with 6 or 8 antennas.Pics are in gallery album;

http://www.digitalhome.ca/forum/album.php?albumid=40
 

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hoosierdxer,

Interesting antenna experiments you’ve conducted.

Have you shared your tower setup? I have one mounted on my patio roof (~9’ up) that hinges @ the base. It is raised & lowered by an electric winch & stainless steel cable. I looked in your album (http://www.digitalhome.ca/forum/album.php?albumid=40) & it looks like you have a crank-up tower. Do you lower it and manually tip it over? Or have you designed a more elaborate scheme?
 

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ten cent tour

Not all that elaborate but it's handy and quick.I've had this old Heights 64 footer for some time now. 16 ft sections(4) so it goes low to hide from the wind & lightning. You can see in the pics there are two worm gear winches. I remove the handles and JB Weld an extra nut,or coupler nut and use the drill w/ socket on it.Takes around 2min to lower and 3 back up.This tower has a 26" base section so I had to make an adapter plate from 1/2" steel to transition from a smaller Aluma Tower I had previously. The base is not to spec for this freestanding tower,so I use 3/8" black double braided Dacron guy ropes from the previous tower.These ropes are over 15yrs old and are still like new.Good stuff. The rotor is a Yaesu G800DXA mounted 7ft down.I use 1-1/4 Sch40 Aluminum for masting and stiffen it up with 1" galv pipe inside that extends 5ft above the top bearing past the Aluminum.This way I can build mast for any arrangement out of 1-1/4" Aluminum and slide it down over the 1" pipe and tighten with set screws.Plus,I make a 1ft long clamp by slitting 1-1/2" galv pipe and use 4 muffler type clamps on that joint.Makes for a very stiff mast above the tower but flexible for making changes.
Pics;





All photobucket pics;

http://s498.photobucket.com/user/locknut-1/library/Antennas-Dxing?sort=3&start=20&page=1
 

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Tower Mount Rotor

I've brought this up before and got a nice pic from loveota:

http://www.digitalhome.ca/forum/1272664-post1612.html

but need more specifics on exactly how the rotor is mounted to the tower.

Is the rotor bolted to the tower plate or is their another piece to join the rotor to the tower?

Is there a special sheath or something where the mast exits the tower top?

Is a thrust-bearing used and where is is placed?

Additional pics would be great. Thanks
 

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Thanks for the pic BOUVAL.

I guess there are a few ways to do it, but I would like to have the rotor mounted to the tower or tower plate because of my 2 antenna set-up.

I know if you are going to go with a two mast set-up, the top mast which is supported by the rotor should be as short as possible, ideally 12 inches or less. In my situation I have two antennas (VHF/UHF), so the top mast cannot be very short. I guess I could shorten the distance between the two antennas, and then lengthen the lower mast... But ideally, I would like to go with the single mast set-up with the rotor mounted inside the tower, a thrust-bearing and a single mast.
 

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Is the rotor bolted to the tower plate or is their another piece to join the rotor to the tower?
The rotor sits on an accessory shelf inside the top section of a Rohn 25G.
ROHN 25G | Communications Tower Specifications, Prices, and Availability Here
ROHN 25G Tower Top Single Accessory Shelf R-AS25G

http://www.dxengineering.com/parts/roh-as25g

Is there a special sheath or something where the mast exits the tower top?
The top cap section can be ordered with different diameter tubes for the mast.
ROHN 25G Tower Sections
ROHN 25AG 9 Foot Top Cap Tower Section with 2 inch O.D.
Is a thrust-bearing used and where is is placed?
If you use thrust bearing, it would mount on a thrust bearing plate on a standard tower section.

buyers guide:
http://www.3starinc.com/manuals/25G_buyers_guide.pdf

see also
ROHN Products at DX Engineering

Rohn website:
http://rohnnet.com/
 
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