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RE: Tower Idea



Hi Les:

I also work the sats and have the UST HDTX-72 with Orion rotator and F12
beams. I personally would not put the satellite antennas at height. I would
add a 6M beam on that mast and call it a wrap. The sat antennas do not need
much height (duh) except for ground clearance with the longer boom antennas.
Also, you are going to want an S-band dish at some point with the new P3E
coming soon. Putting a 60 cm dish at height invites wind trouble. The advice
during storms is to 'birdbath' the dish -- this means other antennas on a
crossboom could rotate vertically and clobber your HF antenna. You are also
going to futz around FAR more with the sat setup than the HF setup - with
mast mounted preamps, downconverters, etc. Also, at those frequencies, at
150+ feet, you'll need hardline or at least LMR-600 even if you are
downconverting at the mast to 2M. I would recommend a smaller separate tower
- say 20 feet of Rohn 25 with a flat-top, separate the G-5500 and put the
elevator at the top of a 8 foot mast with a Max-Gain solid fiberglass 20
foot crossboom and mount sat antennas to your heart's content.

If you have a SPG panel close to your house, your 4" PVC should Y at some
point under ground to go to each tower with 'dog houses' at each tower. That
way you can mount all your lightning suppressors easily on one panel for
both towers and run LMR-600 from SPG to the HF tower and maybe use LMR-400
on the SAT array, if you are say 100' away. I use Bury-Flex up the HF tower
and in close to the rig, and LMR-400 with the sat antennas and its rig.

This is what I've done.  Hope this helps.

73, Jamie
WB4YDL

-----Original Message-----
From: owner-AMSAT-BB@amsat.org [mailto:owner-AMSAT-BB@amsat.org] On Behalf
Of sco@sco-inc.com
Sent: Wednesday, April 20, 2005 7:24 PM
To: amsat-bb@amsat.org
Subject: [amsat-bb] Tower Idea

I would like comments on the following proposed idea for a tower
arrangement:

US Tower TX-72 with motor drive and crank over (72 feet in height plus 10 - 
15 feet of mast above the top of tower).

M2 rotor to turn the mast.

Force 12 XR-6A  (10-40m Yagi on a 18 ft boom) mounted about one foot above 
the top of the tower.

Yaesu G-5500 rotor mounted "pole style" at the top of the mast. It would 
have my short M2 yagis for 2m and 70 cm plus dish for S Band.

If I put the satellite array on the HF tower there will be at least a 150 
ft (min) cable run to the tower from my shack, plus another 50 feet up the 
tower.

This combination would give me at least a 10 ft maximum separation between 
the antennas. Should be fine then with no interference problems for the 
Force 12 or the satellite array (since it would be on the top). Since the 
tower would be a crank over i should be able to get to the satellite array 
to do adjustments. The M2 rotor is very very strong and dependable and 
accurate so there would be no problem to turn the array for HF work or have 
it stopped at a known heading for the satellite rotor (G-5500) to take over 
when i wanted to do satellite work.

Is this a practical and workable approach?  I do NOT want to use the G-5500 
to turn my HF antenna because I have my HF and satellite stations in two 
separate desk areas of my "ham shack". plus I do not like the look and feel 
of the G-5500 for HF work. Therefore that is not an option. I either do the 
above or need to put up two separate towers, one for HF and one for 
satellite. Because of the issues with my trees (I am in a forest, it looks 
like) that would require at least an 80 ft+ tower (to clear my trees) for 
satellite work. Has anyone pole mounted a G-5500 small satellite array on a 
10 -15 ft mast at the top of a 72 ft motor driven crank up/crank over tower?

If this can be done it will save me at least $4-7,000 plus I will have a 
motor drive on my HF tower (which i would not do if I must buy two towers).

Les
W4SCO
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