If using a steel mast then first calculate the RF resistance at the
frequency of operation. The RF integrity at the various junctions is also
far from ideal.
Aluminum is still the best for a radiator and with several others helping on
the guys that HyGain mast should go up OK. They wouldnt be selling them if
they didnt work.
One way to secure the sections is to drill a small hole thru the louvered
part of the hose clamp into the mast and secure with a SS #6 self tapping
screw. Dont use a screwdriver to tighten the clamps, a socket on a ratchet
wrench gives more torque. Assemble the sections with a small amount of
Penetrox or similar to protect against corrosion.
Carl
KM1H
----- Original Message -----
From: "Rob Atkinson, K5UJ" <k5uj@hotmail.com>
To: <towertalk@contesting.com>
Sent: Monday, August 20, 2007 2:16 PM
Subject: [TowerTalk] Hygain pushup masts for 80m verticals?
> Hi Neal,
>
> If you are writing about the mast that's aluminum, 65 feet tall and uses
> 11
> six foot sections, I'd avoid it myself. The bottom is 2" o.d. and this
> tapers down to around .6" at the top. Personally, I do not like the idea
> of
> 11 sections (too rickety), and I don't like the idea of all of them being
> held by friction with hose clamps. All that plus it being aluminum and my
> feeling is that you'll be guying a wet noodle. Steel mast is bad enough
> at
> that height but at least it has enough rigidity to be guyable. If you
> want
> 60 feet cheap, the best height/dollar way I know of is to get one of those
> 50 foot steel pushup masts and put it on an insulator and use some sort of
> stainless steel whip on top to get the last 9 or 10 feet. You'll have to
> guy it and you'll need help putting it up but if you do it right it should
> stay up. The aluminum mast may be another story.
>
> Another way is to get 4 used sections of rohn 20 or 25, stack them and go
> the last 20 feet with an aluminum tube from Penninger Radio. This is
> actually better except that you have to figure out how to insulate the
> tower
> base and prevent a reaction between the aluminum and the zinc galv. on the
> top tower section. You'll have to guy the tower part at its top.
>
> 73,
>
> rob / k5uj
>
> _________________________________________________________________
> See what you're getting into.before you go there
> http://newlivehotmail.com/?ocid=TXT_TAGHM_migration_HM_viral_preview_0507
>
>
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