Bob Miller wrote:


I've had good luck bringing 450-ohm line through the window using
MFJ's 4602 window feed through board. It has ceramic feed through
insulators for the balanced line, more feedthrough's for a random
wire, three coax lines and a ground wire. Even includes weather
stripping and a burgler bar.

Bob
k5qwg
That's through a window, not through a wall. I use the MFJ myself.

If I did want to use non-resonant antennas I would locate a tuner at the
antenna feedpoint, not at the generator (transmitter).

"Dave" wrote in message
m...
Bob Miller wrote:


I've had good luck bringing 450-ohm line through the window using
MFJ's 4602 window feed through board. It has ceramic feed through
insulators for the balanced line, more feedthrough's for a random
wire, three coax lines and a ground wire. Even includes weather
stripping and a burgler bar.

Bob
k5qwg
That's through a window, not through a wall. I use the MFJ myself.

If I did want to use non-resonant antennas I would locate a tuner at the
antenna feedpoint, not at the generator (transmitter).


Then you would cheat yourself of a fair amount of propagation and some of
the lower and higher frequencies available with such a set up.

You're not going to keep RF out of the shack, regardless of which system you
use. You might be able to keep some of the hot spots outside, but often
times they are close enough to the station that it is really a waste of
time.

This fascination with resonance is a leftover from CB thinking. How many
warships utilize resonant antennas? Yet they communicate the world over.

The aversion to transmatches is a ham cultural trait that has no basis in
reality, just as the CB'ers are hooked on resonant 50 ohm antennas. It's a
characteristic of the culture(s) of both types of operators, with no basis
in practical operating engineering.

Ed, N2ECW

Ed Cregger wrote:
You're not going to keep RF out of the shack, regardless of which system you
use.

My no-tuner HF antenna system at: http://www.w5dxp.com/notuner.htm
has negligible measured RF-in-the-shack even though the antenna is
a non-resonant length on most HF bands.
--
73, Cecil http://www.w5dxp.com

On Jan 8, 7:50*am, "Ed Cregger" wrote:


The aversion to transmatches is a ham cultural trait that has no basis in
reality, just as the CB'ers are hooked on resonant 50 ohm antennas. It's a
characteristic of the culture(s) of both types of operators, with no basis
in practical operating engineering.

Ed, N2ECW

I wouldn't say that. As an example, I've done tests showing that no
matter how careful I am with the tuner, it's settings, decent open
wire feeder, etc, I could never quite equal the performance of a coax
fed
dipole when feeding the same antenna using the tuner and ladder line.
Quite close granted, and to many people a non issue, but there *was*
a difference. Of course, the coax fed dipoles I use would generally
be considered a single band antenna. But that's no problem here.
But if I have my way, I avoid tuners if possible. I'm trading the
ability of fairly efficient multi band use, for the slightly more
efficient
coax fed single band antenna. I want to radiate every drop of RF I
can.
Also the settings of the tuner are fairly critical for the most
efficient
use. I have a 989c also, and I have done extensive testing with it
using various settings vs efficiency.
I found with the usual T network tuner such as the 989c, you might
be able to tune a load with 25 or more settings. But only the setting
using the least inductance will be fairly low loss. All of the
settings
that use more inductance than required show more tuner loss.
Up to about 20% of your power is lost in a worst case scenario.
So that is another issue. Small, being as one can make sure to
use the least inductance, but it's just another thing to fuss with
when changing bands.
Myself, I prefer to use multiple element antenna elements to
provide multi band capability. The system efficiency is very high,
and I don't have to do anything when I change bands.
It's not using a resonant antenna that makes it very efficient.
It's the ability to use the 50 ohm radio to a low loss 50 ohm
feed line, straight to the appx 50 ohm antenna without any
semi lossy mickey mouse stuff in between. :/
Now if I were required to use only one wire for all bands, I
wouldn't have any problems using ladder line and the tuner
to feed a single dipole. It will work quite well, and being I don't
have the coax fed to compare to, no one will notice the
difference.
But I bet they would notice a slight difference if I did have
both to compare to. The reason I know this is because I
have tried it. "75m" I could see the difference on receive, no
real need to compare on air reports.
But I did anyway, and as expected, they saw about the
same difference between the two systems.
When comparing the ladder line and tuner system vs the
coax system, if I had a signal that was 40 db over S9
on the tuner system, it would bump up to about 45 db over
S9 with the coax feed.
For me to see that large a difference on receive, the tuner
loss can not be considered to be just an illusion or not
based in reality.
I have no problems with anyone else using one, but I think
it's a stretch to say that anyone that prefers to avoid one
is trying to emulate a CB'er.. :/

wrote:
On Jan 8, 7:50 am, "Ed Cregger" wrote:

The aversion to transmatches is a ham cultural trait that has no basis in
reality, just as the CB'ers are hooked on resonant 50 ohm antennas. It's a
characteristic of the culture(s) of both types of operators, with no basis
in practical operating engineering.

Ed, N2ECW

I wouldn't say that. As an example, I've done tests showing that no
matter how careful I am with the tuner, it's settings, decent open
wire feeder, etc, I could never quite equal the performance of a coax
fed
dipole when feeding the same antenna using the tuner and ladder line.
Quite close granted, and to many people a non issue, but there *was*
a difference. Of course, the coax fed dipoles I use would generally
be considered a single band antenna. But that's no problem here.
But if I have my way, I avoid tuners if possible. I'm trading the
ability of fairly efficient multi band use, for the slightly more
efficient
coax fed single band antenna. I want to radiate every drop of RF I
can.

There are actually a couple of different consequences to using a
non-resonant antenna, and they're often confused or lumped together. The
first is the potential for tuner loss. In many, but not all cases, it
can be made negligible -- after all, 25% power loss is only a little
more than 1 dB. But of course no argument can be made against someone
who considers "every drop" -- even a fraction of a dB -- important. The
rest of us can usually use a tuner without any perceptible reduction in
signal strength. We do need to keep in mind, however, that there are
cases where tuner efficiency can be truly bad, and avoid them when possible.

But amateurs tend to use multiband antennas without any thought at all
to radiation pattern. When the frequency gets considerably higher than a
dipole's resonant frequency, the pattern changes. So there's a good
chance that the pattern will have nulls in at least some directions
where you might want to communicate. In those cases, the difference
between a half wavelength dipole and much longer dipole can be striking.
People who don't understand the reason for the difference often
mistakenly attribute it to a change in efficiency rather than pattern.

Also the settings of the tuner are fairly critical for the most
efficient
use. I have a 989c also, and I have done extensive testing with it
using various settings vs efficiency.
I found with the usual T network tuner such as the 989c, you might
be able to tune a load with 25 or more settings. But only the setting
using the least inductance will be fairly low loss. All of the
settings
that use more inductance than required show more tuner loss.
Up to about 20% of your power is lost in a worst case scenario.
So that is another issue. Small, being as one can make sure to
use the least inductance, but it's just another thing to fuss with
when changing bands.
It's relatively easy to measure tuner efficiency when it's working into
a nice resistive load. But I'm curious about how you measured the power
the tuner was delivering to a more realistic non-resonant load
impedance. The only way I can think of to do it with any semblance of
accuracy is to connect two identical tuners back-to-back and measure the
power out of the combination. Is that how you did it? If not, how?

. . .

Roy Lewallen, W7EL

On Jan 8, 11:31*am, Roy Lewallen wrote:


But amateurs tend to use multiband antennas without any thought at all
to radiation pattern. When the frequency gets considerably higher than a
dipole's resonant frequency, the pattern changes. So there's a good
chance that the pattern will have nulls in at least some directions
where you might want to communicate. In those cases, the difference
between a half wavelength dipole and much longer dipole can be striking.

That's another reason why I prefer the separate elements for multi
band use, vs the single wire.
I generally prefer the normal dipole pattern on most of the bands
I use.



It's relatively easy to measure tuner efficiency when it's working into
a nice resistive load. But I'm curious about how you measured the power
the tuner was delivering to a more realistic non-resonant load
impedance. The only way I can think of to do it with any semblance of
accuracy is to connect two identical tuners back-to-back and measure the
power out of the combination. Is that how you did it? If not, how?

It's been so long since I did that, I forgot exactly how I came to
that conclusion.
But I think I was using my resonant coax fed dipole as the load,
and pretty sure I had dual watt meters. One before the tuner,
and another after the tuner. The tuner has an antenna switch
to bypass the tuner.
I believe what I did was measure the power on both meters with
the tuner bypassed, and then tried using the tuner as a "line
flattener", more than an actual tuner, being the system was
already resonant.
I tried various settings of the tuner, trying quite a few variations
in inductance vs cap settings to see if I could notice much loss
with the tuner inline. The radio was my old IC 730 and I used
full power for the tests. The meter after the radio was used to
verify the appx power from the radio, and it stayed fairly constant
in all the tests. The meter after the tuner was used to check
the power at that point in the line.
In all cases, the tuner would indicate a "flat" match with all
the various settings, so any variation in the output of the
radio should have been small, and the meter after it verified
this.
But the meter on the other side of the tuner could vary
anywhere from about 20% less, to almost unnoticeable
difference, depending on the inductance setting of the tuner.
This test didn't tell me much about the losses using
non resonant loads fed with ladder line, but I suspect that
the loss would still be greatly defendant on the inductance
setting.
I would think the loss would greatly vary just depending
on the load at the moment. Could be high, as if feeding a
half size dipole with a T network tuner, or pretty low with
other longer wire lengths.
I didn't try to worry about the exact loss in numbers, but
I could see the problem cropping up fairly easy if one were
lazy about using the least inductance setting, or if using a
tuner with a tapped coil that was not the optimum setting.
My tuner uses a roller inductor, which lets me tune to
exactly the best spot on the coil, but some tuners tap
and switch the coil position. With some of those, loss
could be more noticeable if it's compromise setting was
way off from optimum.
Another thing I noticed that was it didn't take a whole
lot of extra inductance for the losses to begin to show.
Basically, I found there is only one tuner setting that
will give you fairly low loss in such a case. The one
using the least inductance to get a usable match
for the radio. All the other settings would show quite
a bit more loss, and it didn't take too much more
inductance to start seeing 10-15-20 % decreases in
output from the tuner. And all these settings show
a perfect match to the radio.
But if using the least inductance in such a case, the
meter reading was so close as to almost be the same
vs bypassing the tuner.
So you can use a tuner and have low loss if you
are careful about tuning.
Sure, even 20% won't make much of a difference on
the other end, but I'd prefer not to lose it none the less.
I'm usually on the noisy lower bands, and I rarely run
an amp anymore. That's why I insist on every drop.
In the summer, I usually need every drop.. :/
I also prefer coax anyway just due to the convenience.
But if I run ladder line, I run ladder line the whole way.
I don't like running coax to ladder line. I either use
one or the other.

wrote:
When comparing the ladder line and tuner system vs the
coax system, if I had a signal that was 40 db over S9
on the tuner system, it would bump up to about 45 db over
S9 with the coax feed.

Balanced tuner or balun plus unbalanced tuner?
If balun, what kind? Was the balun seeing its
designed-for impedance?

What do you think would be the A/B results for
a resonant coax-fed dipole vs my notuner dipole?

http://www.w5dxp.com/notuner.htm
--
73, Cecil http://www.w5dxp.com

On Jan 8, 12:48*pm, Cecil Moore wrote:
wrote:
When comparing the ladder line and tuner system vs the
coax system, if I had a signal that was 40 db over S9
on the tuner system, it would bump up to about 45 db over
S9 with the coax feed.

Balanced tuner or balun plus unbalanced tuner?
If balun, what kind? Was the balun seeing its
designed-for impedance?

What do you think would be the A/B results for
a resonant coax-fed dipole vs my notuner dipole?


Probably about the same. In theory you would have
slightly less loss than the coax, but at the lower
frequencies even the coax has very low loss.
So being the losses for both are very low, I don't think
you would be able to see much difference.
Or that's my gut hunch anyway..
Yours would probably be better than the coax if the
run was several hundred feet. At that distance, the
slight difference might begin to show up more.
Also if used at fairly high frequencies, you might
have an advantage. Depends on how good the coax
is how much it would be.

On Thu, 8 Jan 2009 08:50:33 -0500, "Ed Cregger"
wrote:


"Dave" wrote in message
om...
Bob Miller wrote:


I've had good luck bringing 450-ohm line through the window using
MFJ's 4602 window feed through board. It has ceramic feed through
insulators for the balanced line, more feedthrough's for a random
wire, three coax lines and a ground wire. Even includes weather
stripping and a burgler bar.

Bob
k5qwg
That's through a window, not through a wall. I use the MFJ myself.

If I did want to use non-resonant antennas I would locate a tuner at the
antenna feedpoint, not at the generator (transmitter).


Then you would cheat yourself of a fair amount of propagation and some of
the lower and higher frequencies available with such a set up.

You're not going to keep RF out of the shack, regardless of which system you
use.

FYI my 80 meter dipole with ladder line all way to the indoor tuner
does not emit RFI in the shack that I can notice, even when put into
all band use.

bob
k5qwg

You might be able to keep some of the hot spots outside, but often
times they are close enough to the station that it is really a waste of
time.

This fascination with resonance is a leftover from CB thinking. How many
warships utilize resonant antennas? Yet they communicate the world over.

The aversion to transmatches is a ham cultural trait that has no basis in
reality, just as the CB'ers are hooked on resonant 50 ohm antennas. It's a
characteristic of the culture(s) of both types of operators, with no basis
in practical operating engineering.

Ed, N2ECW

Ed Cregger wrote:
"Dave" wrote in message


If I did want to use non-resonant antennas I would locate a tuner at the
antenna feedpoint, not at the generator (transmitter).


Then you would cheat yourself of a fair amount of propagation and some of
the lower and higher frequencies available with such a set up.

You're not going to keep RF out of the shack, regardless of which system you
use. You might be able to keep some of the hot spots outside, but often
times they are close enough to the station that it is really a waste of
time.

This fascination with resonance is a leftover from CB thinking. How many
warships utilize resonant antennas? Yet they communicate the world over.

The aversion to transmatches is a ham cultural trait that has no basis in
reality, just as the CB'ers are hooked on resonant 50 ohm antennas. It's a
characteristic of the culture(s) of both types of operators, with no basis
in practical operating engineering.

Ed, N2ECW

You don't read very well. And you seem a tad hostile.

I stated no "aversion" whatsoever to what are called "non-resonant"
antennas. I said that I'd locate the tuner at the antenna feedpoint. A
transmatch between the radio and the transmission line does little to
make the antenna work better.

CB thinking? You really have issues.