portable mast results

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From: Jim.Nestor@ey.com
Date: Tue Sep 05 1995 - 11:13:24 EDT


Thanks for the many quick responses to my request for ideas for a portable
antenna mast from builder's supply type materials. I made a couple of stops
at Home Depot and K-Mart to checkout the options. Here's a quick synopsis of
my findings.

1) longest telescoping paint pole I found was only 12 feet for about $15.
Passed on that one.

2) bought 4 @ 5' wooden paint poles for around $2.75 each. Nice straight and
lightweight hardwood with broomhandle threads on one end.

3) found 8' lengths of aluminum tubing for about $1 per foot. Sizes jumped
from 3/4" to 1" to 1-1/4", too loose for telescoping.

4) longest fishing pole was a 12' Shakespeare surf casting rod with guides,
handles, etc.. for about $50 - obviously a non-starter.

Tried all the scrap tubing I had and couldn't find anything suitable to join
the 5' handles. Too bad, would have made a nice non-conductive 20' pole.
When time permits, may get some hardwood and bore it to make couplings.

Ended up using some pieces of thickwall fiberglass tubing I once bought at a
hamfest. I had three pieces about 1-1/4" OD and one piece that fit nicely
inside that. I screwed the spicers in place with sheet metal screws so the
whole thing broke down into 4 pieces. When stacked without benefit of
anything but gravity to hole them together, I had a 20' mast which I could
easily walk up and sit over a large spike driven in the ground. A few nylon
guide ropes and stakes hold it in place.

I tied the 4 pieces together with some bungy cord and strapped them to the
cartop carrier. Rather bulky but it worked. Aside from some strange wailing
at certain road speeds as the wind resonated through the "pipes" it rode
just fine. Maybe with some pruning, I could have free music on the trip....

For an antenna, I followed an idea somebody mentioned and placed the MFJ
Random Wire Tuner at the base of the mast feeding a non-resonant length of
hookup wire as a vertical. I added four radials for 20m and 2 for 30m
connected to the tuner and fed it with about 50' of RG58 on the ground up to
the operating position. I used the MFJ SWR analyzer and a short piece of
coax to set the tuner then replaced it with the 50' of RG58. Nice flat match
on both bands.

Because of family outing, granddaughter and such didn't get much air time.
However, in an hour on Sunday worked IK1, 3Z2, F6, and PA3 with 3watts on
20m. Guess it works!

Still searching for the ultimate portable mast, but have more time now that
the camping season is almost over. Would like it to be smaller and lighter
than the heavy stuff I used. Also, would be nice if it all telescoped into a
single tube for easier transportation. Could even take 2 of them...

May order some aluminum from Texas Towers, e.g. 4 @ 6' lengths from 1-1/4
down to 3/4. That way I'd have a 20' mast that could serve as a vertical
itself or as a support for a dipole or end-fed Zepp. We'll see.

Thanks again for all the ideas, this list is GREAT!

72,

Jim, WK8G
jim.nestor@ey.com


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