[amsat-bb] Re: Tower suggestions....

[Edward Cole]

Rod,

Sounds good. Rohn-45 really much more tower than needed for the 
antennas you are considering.  I am using a 50-foot Rohn-25 to 
support two 6m beams, HF Tribander, 222 and 432 antennas.  My tower 
is also uses a house bracket (HB from angle-iron) at about 12-feet 
(but this is from ground where I use a hinge-over plate in concrete 
slab (12-inches deep).  At 45-feet I do have guys, but you need not 
use them on your shorter tower.  I see no problem attaching the tower 
to your deck if you use large bolts backed with metal plates.  I 
suppose you will use a std tower base plate or the hinge-over plate.

On item caught my attention: the height above your roof (7-feet).  If 
you check the length of the 436CP42 and 2MCP22, both are about 
18-feet long.  When elevated to 90-degrees (straight up) they will 
need a min of 9-foot clearance (best make it 10) to your roof.  You 
can extend using a mast to the elevation rotator above the tower 
top.  I plan to use a single Rohn-25 ten-foot tower top to support my 
satellite antennas using the B5400 az-el rotator mounted about 5-feet 
above the tower.  I have the 436CP42 and a KLM-22C (predecessor to 
the M2CP22), plus a 33-inch dish for 2400.  Sounds like your setup 
will be quite similar.

I using the hinge-over plate so I can layover the complete tower for 
antenna maintenance.  One section is easily raised by hand by two 
people.  You might secure a pulley to the house and raise the 
complete tower buy a cable and hinge-over base.  20-foot tower + 
5-foot mast would likely require using a car or ATV to pull the cable 
(but a good work party of 4-hams might do it with a stout rope).

I have the Rohn bronze mast bearing for 1-1/4 inch mast (it is not 
needed as I went with the Rohn bearing plate and thrust bearing on my 
50-foot tower) if that would work for you?  Might not fit Rohn-45.

Ed - KL7UW

At 04:43 PM 5/13/2007, Stargate wrote:
>         OK, I'm in my final (I hope) figuring for my antenna/tower 
> installation.
>I'm considering mounting the tower on my deck which is made from 2" x 6"
>decking with 2" x 8" rafters on 24" centers.
>The deck is sitting on 6"x6" posts and is VERY WELL supported. There are 7
>of the 6"x6" posts
>supporting the 20' x 20' deck. The deck is only about 4 years old and is
>VERY sturdy.
>
>         The tower will be Rohn 45G and the gable of my house is 13' 
> above the top
>of the deck.
>I am going to use a house bracket near the top of the first section at
>approximately the 9' level
>and one or two sections on top of that. Probably one section will be enough
>and will put the top
>of the tower about 7' above my metal roof which is well over 1/4 wavelength
>on even on 6M.
>--------snip

73,
Ed - KL7UW
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