"It worked great, 1:1 SWR...."
Where was this fantastic SWR measured? .. at the antenna? .. or at the
far end of the feedline? I'll bet that it's the latter case.
The balun and hairpin are designed to obtain the best SWR on this
tri-band antenna while eliminating [to the best extent] the currents on
the coax shield ...
For Field Day .. anything that 'seems' to work ...WORKS! [been there ...
done that!
Put the balun and hairpin back on and I'm sure you'll find the antenna
actually does what it is DESIGNED TO DO.
Don
N8DE
RICHARD BOYD wrote:
Let me ask you TB5EM guys a question.
I have had one for years and use it every year for Field Day on our RTTY
station. We pressed it into service when someone said, "Anyone have a
tribander we can use?" and I had it here in storage. Quickie-style, we just
attached center conductor and braid, each, to each side of the split driven
element with stainless steel hose clamps, didn't use the stainless steel
screws that go through the tubular Cycolac (or whatever it is) insulator at
the center. It worked great, 1:1 SWR, the appropriate SWR curve, good gain
and directionality. We have never seen any reason to change it. I've put
it up on a portable tower at home and have been using it and it's been very
effective here too. I came across a second TB5EM and plan to feed it the
same way and have them up in a stack.
So, getting to the question: What degradation in performance should I be
expecting to see by virtue of not having the balun or hairpin?
73 - Rich, KE3Q
----- Original Message -----
From: "Don Havlicek" <n8de@thepoint.net>
To: <N4CW@aol.com>
Cc: <towertalk@contesting.com>
Sent: Thursday, September 30, 2004 10:32 AM
Subject: Re: [TowerTalk] hairpin
Just measured mine.
The 'loop' is 25.5 inches either side of the boom attachment point, thus
is 51 inches overall.
The shape is almost a continuous curve from driven element attachment
point to boom attachment point EXCEPT the first 3 inches [nearest the
driven element] at quite 'straight' with a bend at the 3 inch point.
Don
N8DE
N4CW@aol.com wrote:
No dimensions are given in the "Assembly Instructions" sheet that I
have.
Direct measurements will have to be made.
Telrex wasn't long on details...,"If you have followed simplified
assembly
sheet carefully, you are ready to connect your 52 Ohm co-axial to the
'Balun'
provided. Mount the antenna in the clear, 34 fet or higher." Also, "Do
not
force, alter, modify, or try any inventions! Telrex has precision-tuned
and matched
this antenna to provide optimum 10, 15, and 20 meter gain, F/B ratio,
and
'balanced-pattern'."
No dimensions, other than hardware sizes, are given.
73,
Bert, N4CW/1
_______________________________________________
See: http://www.mscomputer.com for "Self Supporting Towers", "Wireless
Weather Stations", and lot's more. Call Toll Free, 1-800-333-9041 with
any questions and ask for Sherman, W2FLA.
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_______________________________________________
See: http://www.mscomputer.com for "Self Supporting Towers", "Wireless
Weather Stations", and lot's more. Call Toll Free, 1-800-333-9041 with
any questions and ask for Sherman, W2FLA.
_______________________________________________
TowerTalk mailing list
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http://lists.contesting.com/mailman/listinfo/towertalk
_______________________________________________
See: http://www.mscomputer.com for "Self Supporting Towers", "Wireless Weather Stations", and lot's more. Call Toll Free, 1-800-333-9041 with any questions and ask for Sherman, W2FLA.
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