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 key to using balanced line is to know what impedance you are dealing
with looking into the feedline. If it's too high, baluns don't work. If
it's too low, tuners don't work. You can always measure the impedance
but I have found that EZNEC gives a close enough approximation to the
feedpoint impedance that you don't really need to measure it. Some of
the principles are explained on my web page under "No-Tuner All-HF-Band-
Antenna".
--
73, Cecil http://www.qsl.net/w5dxp

wrote:
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.

The lowest loss is no tuner at all! Let the transmission line do the
tuning. How to accomplish that is covered on my web page under, "No-
Tuner All-HF-Band Antenna".
--
73, Cecil http://www.qsl.net/w5dxp

Cecil, what tests, measurements or calculations have you made to satisfy
yourself that loss in the feedline is no greater than in the tuner the
feedline replaces?
----
Reg.

========================================

"Cecil Moore" wrote
How to accomplish that is covered on my web page under, "No-
Tuner All-HF-Band Antenna".

Jim,
with respect to keeping the system all balanced and running the balanced
line through portals along with metal objects,
you can simply make a length of shielded balanced line using two pieces of
coax with the braids connected at each end and connected to shack ground on
the inside end. It becomes a shielded balanced line of twice the coax Zo and
can be directly inserted into the transmission path with no problems.

Check out "Some Aspects of Series and Parallel Coaxial Cable Assemblies" at
Cebik's site, in particular the "Series-Connected Coax" section

http://www.cebik.com/spcoax.html

73,
John



wrote in message
oups.com...
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

John
I read that link with great interest. Some years back I saw an article
where twinlead was constructed out of coaxial cable for the purpose of
running it through environments that would be bad news for normal
twinlead. I thought it was rather stupid because the loss on such a
line would defeat the whole purpose of using twinlead. However, for my
purposes where I just need a couple of feet or less to be in close
contact with other cableing, this might work. The question is, why
then are remote baluns promoted as the solution to this common problem?
And, is the coax twinlead and a balnaced tuner a better choice than a
short lenght of very low loss coax, a good current balun, and a T
match?
I am not trying to be difficult, I just want to set this up as
efficinetly as possible. This might actually be the key! I just need
to know if I should go with a short section of coaxial twinlead and a
balanced tuner...or leave well enough alone.

John
I read that link with great interest. Some years back I saw an article
where twinlead was constructed out of coaxial cable for the purpose of
running it through environments that would be bad news for normal
twinlead. I thought it was rather stupid because the loss on such a
line would defeat the whole purpose of using twinlead. However, for my
purposes where I just need a couple of feet or less to be in close
contact with other cableing, this might work. The question is, why
then are remote baluns promoted as the solution to this common problem?
And, is the coax twinlead and a balnaced tuner a better choice than a
short lenght of very low loss coax, a good current balun, and a T
match?
I am not trying to be difficult, I just want to set this up as
efficinetly as possible. This might actually be the key! I just need
to know if I should go with a short section of coaxial twinlead and a
balanced tuner...or leave well enough alone.
Great info!
Thanks!

I am not trying to be difficult,

===========================

There's no need to try - you don't appear to have any problems.

Where did you receive your training?

Now that was helpful !
Maybe you should sign up with the local radio club as an Elmer?
No one is forceing you to read my posts or help me.
Thanks anyway.

On 7 Dec 2004 09:56:10 -0800, "
wrote:

Now that was helpful !
Maybe you should sign up with the local radio club as an Elmer?
No one is forceing you to read my posts or help me.
Thanks anyway.

Jim, I believe you mentioned you were considering the Palstar balanced
tuner -- I looked at the "inside" picture of it, and the variable
inductors look suspiciously exactly alike the variable inductor in my
mfj-989c unit. I'm not saying that's good or bad -- just thought I'd
mention it...

Bob
k5qwg

Thanks for that info..I would consider that as "bad"..Hi.
But the Palstar reviews that I have read all seem to be quite
favorable.
I am now using an old Daiwa tuner that does a real nice job, but it is
old and uses small 365 mmf broadcast type variables, a dainty looking
coil, and cheap push switches for antenna selection. The cross needle
metering seems to be OK.
I just want to upgrade to something built a bit better, and I am not
fond of Mighty Fine Junk ( no offense intended ), even if they are the
most popular in the world.
I probably will go for a Palstar, but I can't decide on a T match model
or the balanced tuner.
Thanks for the reply.
Jim