[TowerTalk] Base insulators for verticals

[Tim Duffy K3LR]

Hello Arliss!

I suggest you contact Allen Bond, WB4GNT about Rohn 25G base insulators for
your 80 meter 4 square

http://www.mgs4u.com/fiberglass-tube-rod.htm


73,
Tim K3LR



-----Original Message-----
From: towertalk-bounces at contesting.com
[mailto:towertalk-bounces at contesting.com] On Behalf Of w7xu at iw.net
Sent: Monday, July 04, 2011 9:06 PM
To: towertalk at contesting.com
Subject: [TowerTalk] Base insulators for verticals

I'm looking for some suggestions on how to insulate the base of  Rohn 25
tower so
it can be series fed.  This is for a 4-square on 80 meters.  I already have
the tower
on hand, so I'm not really looking for alternatives to using tower as the
radiating
elements.  I've looked through the archives of TowerTalk and Top Band, but
I'm
wondering if anyone has some other ideas.

The options I've found are:

1)  Base insulators carried by DX Engineering, with one insulator in each
leg of the
tower.   They go for about $450 pertower.  I've seen the arguments that
having 
an insulator in each leg is less than ideal, due to torque, etc.,  but each
tower will
only be 60 some feet tall.  This is the lowest cost commercial alternative
I've found.

2)  Commercial AM tower insulator.  I did some investigating and was quoted
about
$1100 per insulator, with of course just one insulator per tower.  I've been
looking
locally for several years and can't come up with 4 used ones, so the used
route
hasn't proven to be a viable option.

3) Power line insulators.   I checked with my power company and they won't
sell
these.

4) Rohn insulated tower section --  These cost about $2000 each now, plus
shipping.
Ouch.

5)  Home made insulator?  I'm willing to go this route if it doesn't involve
finding some
one-of-a-kind items that I probably won't be able to locate locally.   Also,
for those that
have made insulators with Teflon sheet, etc., I also wonder how the shunt
capacitance
introduced into the system affects performance.

Thanks in advance,

Arliss, W7XU
  



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