Greetings
I have been using balanced line for many years and am convinced of its
virtues, particularly since I use a single tuned doublet for multiband
use.
The question I have never been able to get a clear answer on is this;
How critical is it for the balanced line to avoid metal objects?
Specifically, I now use about 6 feet of LMR 400 coax from a Radio Works
remote balun into my shack where I tune the antenna from either a
manual tuner or the auto tuner in my FT920. In order for me to run the
twinlead all the way into the shack there will be about 18 inches where
the twinlead will share a portal that I constructed to get my grounds
and other cables in and out of the shack. Now I always thought this
was a problem area for twinlead, hence the use of the remote balun.
I am considering the purchase of a new tuner and was thinking I would
like a Palstar Balanced Tuner. But can I use it? Would I be better of
with a T match and a short length of coax to a balun, or would a
balanced tuner be better even with the 18" or so of twinlead coming in
close proximity to the other conductors?
I really can not bring the twinlead in without it crossing paths as I
desribed.
Is a balanced tuner all that better than a T match anyway in terms of
antenna performance or loss?
What say?
Thanks

On 6 Dec 2004 08:22:19 -0800, "
wrote:

Greetings
I have been using balanced line for many years and am convinced of its
virtues, particularly since I use a single tuned doublet for multiband
use.
The question I have never been able to get a clear answer on is this;
How critical is it for the balanced line to avoid metal objects?
Specifically, I now use about 6 feet of LMR 400 coax from a Radio Works
remote balun into my shack where I tune the antenna from either a
manual tuner or the auto tuner in my FT920. In order for me to run the
twinlead all the way into the shack there will be about 18 inches where
the twinlead will share a portal that I constructed to get my grounds
and other cables in and out of the shack. Now I always thought this
was a problem area for twinlead, hence the use of the remote balun.
I am considering the purchase of a new tuner and was thinking I would
like a Palstar Balanced Tuner. But can I use it? Would I be better of
with a T match and a short length of coax to a balun, or would a
balanced tuner be better even with the 18" or so of twinlead coming in
close proximity to the other conductors?
I really can not bring the twinlead in without it crossing paths as I
desribed.
Is a balanced tuner all that better than a T match anyway in terms of
antenna performance or loss?
What say?
Thanks

I've tried it both ways: bringing the ladderline to a coiled coax
balun at the window, with coax coming into the shack; and I've tried
bringing the ladderline directly into the shack.

I'm currently doing the latter -- the ladderline comes through the
wood-frame window opening (with a towel and toilet paper plugging up
the air gap), it then passes within 2 or 3 inches of a couple other
cables, and finally goes to the 4:1 balun on my Tmatch tuner. That
seems to work well. I think you have to just experiment and see what
works with each particular antenna.

bob
k5qwg

On 6 Dec 2004 08:22:19 -0800, "
wrote:
Is a balanced tuner all that better than a T match anyway in terms of
antenna performance or loss?

Hi Jim,

I've seen reports of "better tuners" equipped with fans - take warning
that this would be a contradiction of claims and features.

What you fail to discuss is what is motivating you to make this
change? Do you perceive your tuner heating up? Does it fail to tune
your antenna? Are you having problems with Common Mode currents? Are
you bored with the current arrangement?

73's
Richard Clark, KB7QHC

Hello
Well, what concerns me is that I may not have things working as well as
they could be. I'm not having any problems and in fact this system
works out quite well. I have read that a remote balun and coax will
work, and it does, but going direct to a balanced tuner is better. But
how much better? Is it worth the effort and expense? I'm satisfied
that the LMR400 and Radio Works balun are as low loss as I can get for
this kind of system, but I can never leave well enough alone if I think
there is room for improvement.
Thanks

Hello
Well, what concerns me is that I may not have things working as well as
they could be. I'm not having any problems and in fact this system
works out quite well. I have read that a remote balun and coax will
work, and it does, but going direct to a balanced tuner is better. But
how much better? Is it worth the effort and expense? I'm satisfied
that the LMR400 and Radio Works balun are as low loss as I can get for
this kind of system, but I can never leave well enough alone if I think
there is room for improvement.
Thanks

Jim,
The differences between the two 'ways' can be fairly large. But,
on the whole, I honestly doubt if you would 'see' any difference in
performance. Running balanced lines near 'stuff' isn't as big a
'problem' as most people think. If you can stay away from things,
fine. If not, then try to stay as far away as possible, and keep the
proximity of the balanced line to other things 'symetrical' (if that
makes sence), both conductors an equal distance from the other stuff.
'Doc

PS - If the idea is to try something different or new, have at it!

Jim,

Well, let me say this...

I've run window line for years, and will be switching to open wire line, in
part, next year. In a test that I did about 7 years ago, I ran a 1 ft section
of window line across a metal flourescent light fixture, laying right on it. I
could measure no change in SWR and no change in signal strengths using a 40 m
horizontal loop on 40 m. I'd recommend running a test if possible and see if
it makes a difference.

Right now, I run an 80 m loop and run window line all the way to the tuner in
the shack. Only metal is about a foot away, water pipes and heating ducts that
parallel the feedline for about 25 feet. It works so if there is a problem,
it might not be severe and I'm willing to live with it, hi.

73s,

Evan

wrote:
...I can never leave well enough alone...

Hi, Jim -

I know the feeling!

How about a *remote autotuner* that you can build yourself? Sound like a
good winter project? Browse on over to
http://www.ldgelectronics.com/index.html and check out the RT-11.

Best -

Lee H, NB7F

On 6 Dec 2004 09:53:00 -0800, "
wrote:

But how much better?

Hi Jim,

Probably not enough for you to notice.

Is it worth the effort and expense?

Worth is subjective, even if you feel good about, but discern no
evidence of improvement in performance, that may be sufficient.

I'm satisfied
that the LMR400 and Radio Works balun are as low loss as I can get for
this kind of system, but I can never leave well enough alone if I think
there is room for improvement.

As Doc suggests, goferit. Bob's advice is not uncommon either,
although absorbent material could get damp and affect local line
performance. The question then becomes one of our academic knot
twisters in that would it matter. Myself, I see a potential short
across the line and tender nearby to support combustion or smoldering.

To solve my 15X15 inch basement window problem, I replaced the plate
glass with Plexiglas and drilled holes with abandon. This replacement
was not without taking so long a time that my buddy lost his patience:
"Just bust that $5 worth of glass out!" Instead, I had to do this by
carefully removing the petrified putty all around - and cracked the
pane in the last nip. Care and precision is not always worth the
effort.

73's
Richard Clark, KB7QHC

I considered a remote tuner and did in fact use the RT-11 for a couple
of years. It worked, but it was a bit troublesome. What I am doing
now is far better.
One of the things I have learned about autotuners is that they all seem
to have a higher insertion loss than a good manual tuner. Probably
due to the toroids, fixed caps, and relays they use. Good airwound
coils and variable caps are less lossy. So using an autotuner may be
convenient, but I have seen insertion loss figures as high as 65%
under some mismatch conditions!..
I can live with my current system, and it works just great. But since
I am in the market for a new tuner, I just wanted to know if I should
go T match or balanced, as I originally stated.
Thanks for all the feedback!
Jim