I did not notice the 4 foot coax when I first read the post. This is
likely too short for a rotator loop and it makes me wonder if the antenna
is being tested on saw horses near the ground. I just checked my 10m
model and the SWR (normally 1.1:1) goes to over 2:1 when 3 foot high.
John KK9A
from [Ray, W4BYG] [Permanent Link][Original]
To: "'John Lemay'" <john@carltonhouse.eclipse.co.uk>, "'James Archer'"
<James.Archer@erm.com>, <towertalk@contesting.com>
Subject: Re: [TowerTalk] Advice Wanted-Tuning A 10 Meter Telrex Beam
From: "Ray, W4BYG" <w4byg@att.net>
Date: Wed, 2 Jul 2014 11:20:47 -0400
Additionally, I would connect the analyzer with a half wave length of coax
instead of the 4 foot piece. The half wave length will reflect what the
actual impedance at the antenna feed is. The 4 foot piece will only do that
if/when the antenna impedance is actually at 50 ohms. Remember to calculate
the half wave length by the velocity factor of the cable you are using.
Ray, W4BYG
Kindness is the inability to remain at ease in the presence of another
person who is ill at ease, the inability to remain comfortable in the
presence of another who is uncomfortable, the inability to have peace of
mind when one's neighbor is troubled... Samuel Holdenson
-----Original Message-----
From: TowerTalk [mailto:towertalk-bounces@contesting.com] On Behalf Of John
Lemay
Sent: Wednesday, July 02, 2014 11:14 AM
To: 'James Archer'; towertalk@contesting.com
Subject: Re: [TowerTalk] Advice Wanted-Tuning A 10 Meter Telrex Beam
Hopefully, you are taking measurements with the aerial clear of the ground,
and pointing skywards ? Otherwise ground proximity will make an impact.
John G4ZTR
-----Original Message-----
From: TowerTalk [mailto:towertalk-bounces@contesting.com] On Behalf Of James
Archer
Sent: 02 July 2014 14:58
To: towertalk@contesting.com
Subject: [TowerTalk] Advice Wanted-Tuning A 10 Meter Telrex Beam
Tuning a Telrex 10M523 (Telrex 5 element beam on 23 foot boom)
After several days of work on the ground working with the matching system
and trying multiple combinations of driven element length to the Telrex
match position-the best we can get is an SWR of 2.3 at 28.500. We are using
an MFJ tuner through a 4 foot piece of coax to the antenna. Antenna has a
tuned matching stub set for 28.500.
We have followed exactly the specifications from the 5 page Telrex
instructions that are beautifully illustrated.
This is a wonderfully built antenna and we are very keen to get this tuned
up right and in the air working!
Anyone have any golden words of advice, we are of course looking to get the
SWR down below 1.5:1 at 28.500
Thanks in advance for any help you can provide. Replies to N3ZS at
james.archer at erm.com
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