[TowerTalk] Mast Extentions

Jim Reid jreid@aloha.net
Sat, 29 May 1999 12:20:09 -1000

Aloha Fred,  You wrote,  in part:

>So, it seems
> to me you go from a wind load of 6.4 sq-ft to 10.8 sq-ft.
> If your tower can handle that and the lifting load of a new mast, it
> seems like you are in business.

Thanks a bundle for your effort,  Fred.  Gives me some confidence;
I have recv'd several responses,  more cautionary than supportive, hi!

I can not find a spec on the total weight the MA-550 can handle,
but using the US Tower 55 lb.  M-20 galvanized mast and my
39 lb C4  would seem reasonable.  The MA is rated at 10
sq ft in a 50 mph wind with the antenna up at 55 feet.  

Anyway,  I never leave it at 55 feet when the trades begin
gusting above 30 mph or so;  and it is really obvious when
they get that strong,  hi!  With the motor,  it is easy to raise
and lower the tower,  so drop it full down when the wind
goes up.  But with a 15 foot mast extension out the tower
top,  that leaves the antenna still up around 37 feet high
or so with the tower full down.  Probably also ok with a
strong mast.  Have no idea now strong the M-20 galvanized
mast is;  it has 0.12" wall thickness.  Can go to a 0.25 "
wall thickness mast,  but that one weighs 70 lbs,  which
with the C4 brings the total weight to around 110 lbs,
probably a bit much for the MA-550,  not sure.

Anyhow,  again,  thanks,  Fred.

73,  Jim,  KH7M

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