k2vi wrote:
> Hey guys, can someone please advise me on the mast to use, I was looking
> at 2" EMT pipe I saw in the electrical dept at home depot. Keep in mind
> this pipe will be supporting a hy-gain 203BA which has a 16' boom and
> weighs 32# also it will be pushed up from the thrust bearing about 6'. Im
> sure it will be fine here in va beach. Right now im using a galvinized 2"
> shedule 40 pipe that weighs a ton.
>
> tony k2vi
The fundamental problem here is that nearly all amateur antenna
hardware is designed around 2.000 inch masts. So called "2 inch"
water pipe has an outside diameter of 2 3/8 inch. I suspect what
you are using now is "1 1/2 inch" pipe, which has an outside diameter
of 1.9 inches. It will sort of work in some antenna hardware, possibly
requiring shimming. So called "2 inch" EMT has an outside diameter
of 2.l97 inches. Probably won't fit and in any event EMT is designed
to be bent, so it's a non-starter as mast material.
I recently acquired a free "2 inch" mast that turned out to be
2.020 inch outside diameter. Believe it or not, it would not fit
in my K7NV prop pitch nor in my MonstIR mast clamps. It did sort
of squeeze through the thrush bearing and worked with the Slip-Nott
after a fashion. I had to buy a 2 inch mast from Texas Towers, and
that turned out to be VERY close to 2.000 inch diameter. It was
still a tight fit in the MonstIR mast clamps. This gives
you an idea how critical mast diameter is.
Rick N6RK
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