[TowerTalk] Near Full Sized 40M rotatable Dipole

Dan Zimmerman N3OX n3ox at n3ox.net
Fri Aug 4 15:28:31 EDT 2006


Along those lines, jackite.com has 31' fiberglass poles for sale,
about $55 apiece.

I built a ~65% size 40m dipole with 2 20' rods and a loading  /
matching coil in the middle that works rather well.  The 20' fishing
rods were only $19 apiece.  I've never put mine out in the weather for
any time.  I also usually use it verticallly though it goes up
horizontally without a *ridiculous* amount of sag   I think it would
work fine on a tower for some time, and it weighs almost nothing.  It
has < 90kHz 2:1 SWR bandwidth though.

SM2EKM: That looks like a full size 40m ... is it 1/4 wave rods or
would they have been too floppy?  What is the base diameter of those
rods?

The telescoping fiberglass fishing rod is a rather nice boon to the
big-antenna builder.  I'm sure people have had varying experiences
with the survival of such objects on top of high towers in bad
climates, but seeing as I've got about $50 in my shorty-40, I'd be
willing to sacrifice it to the elements and see what happened.

Of course, you've got to consider who and what is going to get hit by
fiberglass splinters from aloft if it breaks.  Maybe not something to
do in the suburban lot without frequent inspection of the antenna.
Aluminum fails more gracefully than the fiberglass will.

Dan


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