[TowerTalk] Mast material

[Richards]

Right, Rick.

Many antenna manufacturers fail to adequately distinguish
between inside and outside diameter.    DX-Engineering sells
a 43 foot monopole made of aluminum TUBING and it starts
with a 2" OUTSIDE DIAMETER (OD) .... TUBE...

But the instruction manual says to mount the tilt plate on a
2 " PIPE,  and PIPE is measured by its   INSIDE DIAMETER
(ID)  --  so if you tell them you are going to mount it on a 2 inch
water PIPE, they say "Great Plan..." - but fail to mention that
the saddle clamps they supply  (measured for 2 inch ID Tubing
work on it - because they really failed to clearly distinguish
between Pipe and Tubing.

Dumb.

The sales guy I called about it  (after sinking my 2 inch water pipe
into a four feet of concrete... says he has a sticky note on his computer
monitor to remind HIM of it...   I wish they had put the sticky note in
the instruction manual!   I had to drill out the 1/4 inch steel plate and
use different sized U-bolts designed for 2 inch PIPE.

But that pipe is WAY stronger than conduit for all the reasons advanced
the other posters.

Just MY take...   YMMV.

=================  Richards - K8JHR  =================

Rick Karlquist wrote:

> 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.  

Probably won't fit and in any event EMT is designed
> to be bent, so it's a non-starter as mast material.
> 

> still a tight fit in the MonstIR mast clamps.  This gives
> you an idea how critical mast diameter is.
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