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[TowerTalk] Telrex Antenna

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Subject: [TowerTalk] Telrex Antenna
From: (Monty Taylor)
Date: Tue, 24 Apr 2001 16:55:47 -0500
Thanks for the reply Wes.  The boom has the five holes already drilled.  The
elements pass through the boom, which has a sleeve also drilled for
re-inforcement.  I really don't think I'm missing any part of the boom.
Maybe Telrex made yagis other than the TB6EM and the TB5EM.  I do have my
Telrex trapped Dipoles still.  I will email Mickey Cox, K5MC, and see what
he thinks.

Best regards,
Monty/WB5GLB since 1967

-----Original Message-----
From: Wes Attaway []
Sent: Tuesday, April 24, 2001 4:45 PM
To: Monty Taylor
Subject: RE: [TowerTalk] Telrex Antenna

The two trapped elements are probably a driven element and the director.
The other three would be reflectors, one for each band (10, 15, 20).  I used
to have one of those antennas, way back around 1962-65 or so.  It worked
really well. I believe the boom was longer than 17', probably about 24' or
26' as I recall.  The boom was in three pieces, so maybe you are missing one
piece.  The center piece on Telrex booms is usually a husky 3" or 3-1/2"
section that the other two pieces slip into.  There is also a very heavy
metal plate for boom-to-mast mounting, and it clamps to the boom with two
real heavy horseshoe clamps.

In any event, you have most of the antenna and should be able to make it
work by doing a little modeling with EZnec or some program specifically for
yagis.  Put the 20M reflector at one end and the other two reflectors
appropriate guesstimated distances in from there and crank up the software.
I would start with spacings and element lengths similar to some other
tribanders of this type of design.  The final results will vary a bit
depending on the actual size and taper of the elements.  You can plug the
element particulars into the modeling software.  I would start with the boom
length you have and see what you get.  If you aren't happy then model the
antenna with a boom in the 24-26' range.  I don't think there is any magic
involved here ..... there are a lot of spacings and element lengths that
will work fine.

I would not worry about the feed impedance until you see what you get with
the model you are otherwise satisfied with.

One other thought.  I believe the ARRL Section Manager for Louisiana may
have one of these antennas.  His name is Mickey Cox, K5MC.  Send him an
e-mail and tell him I said hello!

Wes, N5WA

-----Original Message-----
[]On Behalf Of Monty Taylor
Sent: Tuesday, April 24, 2001 4:05 PM
Subject: [TowerTalk] Telrex Antenna


I posted requests for information on a Telrex TB5EM on this reflector.  The
replies are really great.  I am now beginning to wonder what antenna I have.
The balun is the Telrex balun for sure.  The boom though is only 17 feet,
plus or minus, in length and appears to be 2 1/2 to 3 inches in diameter.
The there are 5 elements and the two trapped elements are definetly Telrex,
with the dooknob capacitors encapusulated on the inductor covered witht the
classic red-orange epoxy sealant.  If anyone has one that even looks like
this, let me know the model number or even if it is a Telrex.  The lack of
knowledge on my part is frustrating!  (I did own a Telrex TB6EM back in

Monty/WB5GLB since 1967

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