Re: [amsat-bb] Crossboom question

[Stan <stan@xxxxxxxxxxx>]

Hello Jamie,

consider a vertical arm from the horizontal boom, maybe 2 to 3' long.

You have a large amount of wind surface area with the dish so
consider:

	aluminum mounting plate 4" x 6" or 5" x 8", 3/16" or 1/4" thick

	2 ubolts to secure it to the H boom and 2 ubolts to secure the
	vertical stub mast to the plate.
	
	Use stainless steel hardware. Of course, grease the threads.

	mount the dish on the vertical stub mast.

The stub mast can be pointing up, above the H boom or pointing
down below the stub mast.

I would probably mount the stub mast as close as possible to the
elevation rotator with the 3' dish mounted above the el rotator.
Be sure to check all conflict with rotator, mast and antennas so
things do not bang together. Centering the dish on the H boom
 would minimize the horizontal, side to side, imbalance

I use the Yaesu G5400 and the M2, 11' 3 piece fiberglas boom
with the 1/4" thick wall, I will never crush it with a u-bolt.

Be sure to paint the fiberglas H boom to prevent UV deterioration,
otherwise it will be "itch" city in less than 1 year.
exterior primer and a finish coat is fine, after cleaning and
lightly sanding.

I do not know the wall thickness of the Max Gain pole.
If it is less than 1/4" wall thickness consider glueing in a
solid fiberglas dowel, in the areas where a external clamp will
applied either for the elevation rotator  or antenna mountings.
Many people crush the thinner fiberglas booms when torquing the
clamps.
Once the fiberglas is crushed/cracked the clamp will never hold
properly.

Do not ask how I know this.... hi.

Stan, WA1ECF   FN41  Cape Cod.



	

"James C. Hall, MD" wrote:
> 
> Hello:
> 
> I'm slowly getting my satellite station together but I have a question.
>   I purchased an 8 foot solid fiberglass crossboom from Max Gain (the
> longest they sell) and have mounted it successfully on the tower with
> M2 430 and 144 MHz CP antennas.  I also purchased a 3 foot W3IYR offset
> fed dish.  It appears that the dish will be a very tight fit between
> the mast/rotor and the 430 antenna.  Options appear to be to off-center
> the crossboom somewhat to allow the dish to fit, or somehow lengthen
> the crossboom (?).
> 
> I would appreciate any help here.
> 
> Jamie
> WB4YDL
> 
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