[TowerTalk] Telrex 40 M Beam restoration
Michael Tope" <W4EF@dellroy.com
Mon, 8 Jan 2001 23:04:32 -0800
Do either of your Telerex 40 meter beams have solid rod stainless steel element
tips? Dean Scarborough, KS8S used to have two 40M329 stacked at 90' and 180'.
As I recall, he had a problem with the stainless steel tips breaking off of the high
antenna. The stack never played very well, but his steel guys were not broken
up at all, so I suspect that this might have been part of the problem.
----- Original Message -----
From: "Tom Rauch" <email@example.com>
To: <firstname.lastname@example.org>; "Chris Kepus" <email@example.com>
Sent: Monday, January 08, 2001 2:52 PM
Subject: Re: [TowerTalk] Telrex 40 M Beam restoration
> Hi Chris,
> > I am in the process of restoring a Telrex 40M329 beam. I would like to
> > contact anyone with experience with this beam and especially someone who
> > is still using this fine antenna.
> I have a 40M346 or whatever the long boom 40 meter antenna is.
> You really need to check some things on that antenna, if it is
> anything like mine.
> Telrex used two types of elements. The piece going to the boom is
> OK, but the next taper has a single wall really thin tubing element
> (as I recall something like .038 wall). Some beams use two thin
> walls sleeved.
> I strutted the elements on mine with tarred nylon supports, but that
> wasn't enough. After a few $400 trips by a crane to repair
> elements, I just totally rebuilt the elements using normal 6061T-6
> .058 wall aluminum with a normal element taper.
> Now the antenna has finally lasted six months without a repair.
> I also found the stock balun was junk. It had a small coil of coax
> and a hunk of house wire in the balun. This balun is probably
> different than yours, since my antenna has a 50 ohm feed it uses a
> 1:1 balun. I replaced it with a homebrew balun. You probably don't
> have the same balun, but the obvious design flaws in my antenna's
> factory balun make me wonder how good the other baluns are. I
> have no idea if the other baluns are OK, just that the factory 1:1
> balun that came with my antenna was poor.
> The director tuning was OK, but the reflector on mine (using factory
> elements) was far too low in the band. When I shortened the
> reflector, F/B ratio became around 40 dB or more (measured)
> compared to a pathetic 15-20 dB stock at the band center. Your
> antenna is different, and may be OK.
> The antenna worked OK with factory reflector settings, but I found
> them more for feedpoint impedance than F/B ratio. When I reset
> the reflector (by watching F/B on a test tower 500 feet away) the
> feedpoint was way off.
> > Also I am interested if anyone has tried using this beam on 20M by
> > altering the feed system and using an antenna tuner?
> I don't see any easy way to do that, I think you'd be asking for
> 73, Tom W8JI
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