Hi
Does anyone know of a manufacturer of an ATU that places a 1:1 balun on
the input side, like the Palstar AT4K does? I like that tuner, but it
is a bit pricey. Just wondering who the competitors are, if any.
Thanks

On 9 Dec 2004 10:25:13 -0800, "
wrote:

Hi
Does anyone know of a manufacturer of an ATU that places a 1:1 balun on
the input side, like the Palstar AT4K does? I like that tuner, but it
is a bit pricey. Just wondering who the competitors are, if any.
Thanks

You could make your own 1:1 balun for a few bucks, and place it on
either side of the tuner. See W2DU's article:

http://home.iag.net/~w2du/Reflection...nProblem. pdf

bob
k5qwg

"Bob Miller" wrote in message
...
On 9 Dec 2004 10:25:13 -0800, "
wrote:

Hi
Does anyone know of a manufacturer of an ATU that places a 1:1 balun on
the input side, like the Palstar AT4K does? I like that tuner, but it
is a bit pricey. Just wondering who the competitors are, if any.
Thanks

You could make your own 1:1 balun for a few bucks, and place it on
either side of the tuner. See W2DU's article:

http://home.iag.net/~w2du/Reflection...nProblem. pdf

bob
k5qwg



Nice article. I guess QST used have technical articles, eh?

Paul AB0SI

Yes, thank you..I have been thinking about modifying an existing tuner
with the balun on the output. The problem is that ALL components must
be isolated from ground. I suppose I could pull that off, but it is
not as simple as you might think, especially with a tuner that uses a
tapped inductor in a T match. I t would probably be easier to float a
roller inductor than a tapped inductor because of the switch. The
caps are usually above ground already in a T match, so thats not a
problem. I'm thinking about it, but it would be nice if there was a
good affordable balanced tuner out there.
Jim

As a ham of over 25 years experience and most of those using a ladder line
fed 80 meter doublet, I would highly recommend procuring an old Johnson
Matchbox. These units were made back in the '50s, very well made and will
match on all bands, except 30 meters, from 80 thru 10 meters.
They are a link coupled transmatch, made excusively for use with ladder line
or twin lead.
There are a lot of them advertised on eBay.

wrote in message
ups.com...
Yes, thank you..I have been thinking about modifying an existing tuner
with the balun on the output. The problem is that ALL components must
be isolated from ground. I suppose I could pull that off, but it is
not as simple as you might think, especially with a tuner that uses a
tapped inductor in a T match. I t would probably be easier to float a
roller inductor than a tapped inductor because of the switch. The
caps are usually above ground already in a T match, so thats not a
problem. I'm thinking about it, but it would be nice if there was a
good affordable balanced tuner out there.
Jim

Hello
Yes I am aware of the Matchbox, having been licensed since 1964. In
those days the Matchbox was still "new", Hi .
They have a limited matching range. They can work great on some
antennas and bands, and not at all on others.
Jimn

wrote
Yes, thank you..I have been thinking about modifying an existing tuner
with the balun on the output. The problem is that ALL components must
be isolated from ground. I suppose I could pull that off, but it is
not as simple as you might think, especially with a tuner that uses a
tapped inductor in a T match. I t would probably be easier to float a
roller inductor than a tapped inductor because of the switch. The
caps are usually above ground already in a T match, so thats not a
problem. I'm thinking about it, but it would be nice if there was a
good affordable balanced tuner out there.
Jim

Jim, your original query and subsequent comments leave a couple of
questions:

1. Is an ATU desired?
2. Will it operate a balanced line? (other antennas as well?)
3. Why is isolation from ground so important to you?

Radio Works puts out some good products, one of them is the Line Isolator
for just the situation you are possibly describing:

http://www.radioworks.com/PDFLineIsolator.htm

However it should be noted that this is offered by Radio Works (in my
opinion) mainly because they promote the Carolina Windom style antennas,
which are designed to radiate vertical components of feedline. Most antenna
types, especially anything using a Balun at the feedpoint would have no such
radiation on the feedline or shield. Antennas requiring good RF ground or
radials would do so, those that don't still require bonding and grounding
for lightning protection, at least in any area that can have lightning. So
the multiple use of line isolators, and/or your insistence on having all
components isolated from ground may correct RF problems that should be
addressed at their cause, and at the expense of maintaining safe bonding and
grounding of the station equipment for lightning protection.

As Bob Miller also added (fwiw): I use two MFJ tuners, the 962D 1.5kw
air-core inductor and the 994 600w ATU "Intellituner". Both perform very
well for me on end fed wires and dipoles. Isolating anything in my station
from ground is out of the question, as it should be for anyone who remains
connected to either or both power and antennas during thunderstorms.

73,
Jack Painter
Virginia Beach VA

Hello Jack
Yes, the tuner is required, because I use a balanced line to feed a
multiband doublet.
The issue is placeing a 1:1 balun at the input of the tuner, rather
than the output. In order to do that with an existing T match type
tuner, all components must be isolated from ground. This is uncommon,
because a typical T match grounds one side of the inductor.
I have read that a 1:1 balun at the input of a T match is desireable
over a 4:1 at the output.
Thanks

wrote
Hello Jack
Yes, the tuner is required, because I use a balanced line to feed a
multiband doublet.
The issue is placeing a 1:1 balun at the input of the tuner, rather
than the output. In order to do that with an existing T match type
tuner, all components must be isolated from ground. This is uncommon,
because a typical T match grounds one side of the inductor.
I have read that a 1:1 balun at the input of a T match is desireable
over a 4:1 at the output.
Thanks

Hi Jim,

I can't imagine what's possibly gained by 1:1 in front of the tuner v. 4:1
(when applicable, some antennas recommend this, including for twin-lead)
after it. Can you recall the writing you saw the recommendation to isolate
from ground before the tuner? I just don't see what it will do for you, but
as I said there is at least one good reason not to do so. Ungrounded and
especially unbonded equipment should be disconnected from antennas and power
supplies before the chance of a thunderstorm. An exception could be if you
totally isolate the antennas from ground, and no balun can safely do that.
But a similar principle called a high voltage isolation transformer could,
and so could a fiber optic isolation transformer. Both are pretty expensive
alternatives to staying with generally accepted lightning protection plans
for the shack. Even if you intend to toss the feed out the window before a
storm, I'm still curious what is gained by a 1:1 between transceiver and
transmatch.

73,
Jack

MFJ has at least a couple of "balanced" devices that place a choke type
balun on the transmitter side of the device. As I recall, MFJ uses a piece
of coax with Teflon dielectric that is surrounded with unknown material.
73 Mac N8TT

--
J. Mc Laughlin; Michigan U.S.A.
Home:
wrote in message
ups.com...
Hi
Does anyone know of a manufacturer of an ATU that places a 1:1 balun on
the input side, like the Palstar AT4K does? I like that tuner, but it
is a bit pricey. Just wondering who the competitors are, if any.
Thanks