Has anyone experience to share regarding a tuner remoted to the tower? I
have used a few manually adjusted tuners and in the marine industry
automatic tuners that typically were programmed for discrete frequencies. I
have used a few remote tuners on marine band HF SSB installations but always
the ltuner was "mated" to a radio both from the same MFG.
My current ham tuner is an LDG AT-1000 Pro II Autotuner. It works
satisfactorily but has several front panel controls which would require
(maybe) interfacing for remote operation. I could do that with little
problems BUT... I have the M-1000 analog meter accessory which allows
switching the meter between forward power, reverse power, and SWR
indications as well as 100 watts FSD or 1000 watts FSD. peak or averagle. It
is highly desirable to keep the meter in the shack when/if the tuner goes
onto the tower.
My previous remote tuner experience includes Collins brand trailing wire
tuners as used on aircraft in flight. I adapted some of these to random
length vertical wire tuners for HF. They just needed a low power sample to
tune on and when tuned gave a signal indicating success and were ready for
high power.
Suggestions, recommendations. alternatives?
TIA for your consideration.
73
Patrick AF5CK
-----Original Message-----
From: Hans Hammarquist
Sent: Wednesday, November 20, 2013 1:04 PM
To: towertalk@contesting.com
Subject: [TowerTalk] Fwd: Limited space for 80 and 50
As a true balanced tuner frequently is just that, an unbalanced antenna will
still cause common mode current in the feed line with a current in the coax
feed to the tuner.
What I understand (and many with me) the "best" approach is to add several
toroid rings on the coax feed to the tuner, and as close to the tuner as
possible. The control cable (if it is a remotley controlled tuner) should be
included in the toroids as well.
The "problem" is that many of us think that a "balanced tuner" is a tuner
with a "floating" output (that would not allow commonn mode current through
the tuner). That would solve man yRFI problems but I have yet to find such
an animal.
73 de,
Hans - N2JFS
-----Original Message-----
From: K0DAN <k0dan@comcast.net>
To: ve4xt <ve4xt@mymts.net>; Jim in Waco wb5oxq <wb5oxq_1@grandecom.net>
Cc: TowerTalk <TowerTalk@contesting.com>
Sent: Wed, Nov 20, 2013 1:47 pm
Subject: Re: [TowerTalk] Limited space for 80 and 50
I agree that the dipole/Zepp is worth rescue. I would consider trying 450 or
600 ohm line.
Ideally balanced antennas should be perfectly balanced, but in my experience
you can tolerate a lot of slop and still have an excellent antenna. Which is
to say you don't need to achieve "perfect" balance. The more balanced the
better, but there is a lot of tolerance in the system.
With the feedline, close proximity to metal objects should be avoided (by at
least a foot...more distance is better), sharp bends in the direction of the
feedline should be avoided. Twist of the feedline is OK, provided it doesn't
fold back on itself. If a small portion of the antenna or feedline is close
to large metal objects (metal roof, window sash, etc.) it is probably OK.
Where large sections of the antenna or feedline are in close proximity to
metal objects, this needs to be changed.
Antenna tuners which claim to handle "balanced lines" should be looked at
with some skepticism. Most commercial tuners are not truly balanced (both
sides should be above ground potential), and if your antenna network has
impedance issues, a T or L tuner may not help things. There are a number of
true balanced tuners: Rich Measures had an article for a homebrew one, and
the EFJ "Matchbox" tuners are link coupled balanced devices. I think there a
few manufacturers who make true balanced tuners today.
Sometimes a slight change in the length of the open wire feedline will help
"tune" the antenna network and achieve better balance (see Cebik articles).
Sometimes a balun or coax choke does not accomplish what is expected of it.
If you are having feedline radiation which is getting into consumer devices,
it is a sign that the antenna NETWORK is out of balance.
While a vertical is a good addition to any antenna farm, so is your
dipole...I'd take a look at what is causing the problem before tearing it
down.
GL es 73
Dan
K0DAN
-----Original Message-----
From: ve4xt@mymts.net
Sent: November 20, 2013 08:20
To: Jim in Waco wb5oxq
Cc: TowerTalk@contesting.com
Subject: Re: [TowerTalk] Limited space for 80 and 50
It would be a shame to not be able to use this dipole, since your vertical
antenna won't come close to it without a lot of radials.
I suspect the problem isn't the antenna but rather the feedline.
I suspect the interference is a combination of feedline radiation and the
Pin 1 problem on your entertainment gear. Even some so-called high-end
consumer electronics suffer from poor engineering.
Have you read any of K9YC's information on chokes and RFI (incl. Pin 1)?
73, Kelly
ve4xt
Sent from my iPhone
On Nov 19, 2013, at 21:57, "Jim in Waco wb5oxq" <wb5oxq_1@grandecom.net>
wrote:
I have a full size 80 meter dipole at 60' in the center fed with 300 ohm
window line to a good tuner with the balanced input. I cannot use it on
80 or 40 meters even at levels of 25 watts or more because of
interfearance to my entertainment center despite snap on chokes on all
input leads and every speaker lead and a high end ac line filter.
Therefore if I want to operate any frequency below 14mhz I feel I must try
a vertical in a side yard located outside the shack. The area is about
25X40 feet. Radials can be put down in that area There is a 50' tower
with a triband beam in one corner of that area. No other metal is in that
area. The feedline length to the shack is about 20'. There is no height
restriction in this area. I only need the antenna for 75 and 40. There
is a 6' tall wood privacy fence around this area. I would hope that using
a vertical in this area would fix the rfi problem since the antenna would
be a good 40' away from the entertainmant center whe
re
as the center of the dipole is directly above it. Suggestions please.
WB5OXQ
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