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Old November 27th 07, 03:05 PM posted to rec.radio.amateur.antenna
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Default using an MFJ-941E tuner on all bands?

James barrett wrote:
... should my thinking be to put up a dipole for 80m and tune it down
to 10, 15 and 40, or should I go with some other length?


An 80m dipole works well on all HF bands. I tune my
80m dipole system by varying the length of the ladder-
line so I don't even need an antenna tuner.

http://www.w5dxp.com/notuner.htm

My favorite bands are 40m and 17m.
--
73, Cecil http://www.w5dxp.com
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Old November 27th 07, 04:35 PM posted to rec.radio.amateur.antenna
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Default using an MFJ-941E tuner on all bands?

On Nov 26, 7:22 pm, "Sal M. Onella"
wrote:

I added two 20m elements of #16 insulated stranded wire (lamp cord,
actually) and ran them downslope toward opposite corners of the garage roof.
They make about a 45-degree angle with the 10m antenna. Construction
articles encourage separating elements of different bands. The first
measured 20m elements were too long and the SWR dipped at 12-something MHz.
I trimmed them to 14.1 MHz, SWR = 1.1:1 at the radio. The only change to
the 10m performance was a very slight increase in SWR (1.5:1 vs. 1.7:1 per
MFJ-269).



Hi, I don't understand how you can add elements to an existing antenna
and have it still work on the band it was originally made for. Do you
still need a tuner? Or do you remove the 20m elements to transmit on
10m?

Jim
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Old November 27th 07, 04:36 PM posted to rec.radio.amateur.antenna
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Default using an MFJ-941E tuner on all bands?

On Nov 27, 3:43 am, "Jeff" wrote:
My naive understanding was that I could hang up a 100ft dipole and use
a tuner to transmit on all bands.


I find that set up extremely lossy on 10GHz

Jeff


Yikes, I don't have anything higher than a 2 meter HT.


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Old November 27th 07, 04:55 PM posted to rec.radio.amateur.antenna
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Default using an MFJ-941E tuner on all bands?

On Nov 26, 5:16 pm, Danny Richardson wrote:

Jim,

Check this one out.

http://www.degendesigns.com/Downloads/TheEasyWay.PDF

Danny, K6MHE


Hi, I like the article. One question about feed lines. If coax is 50
ohms and twin lead has 300 ohms. Why is the twin lead consideres less
lossy than coax? I had thought that higher ohms meant higher impedance
and I thought higher impedance means higher loss. Obviously I have not
read the chapter on transmission lines yet ;-), so I may have that all
wrong.

Also, in the article, I liked the part about before 1950, no one even
heard about swr, and that antennas with high swr were working just
fine. But I make 2 assumptions: 1) I'm thinking, even if they didn't
know or care about swr, they still had to cut their dipoles for the
band they were transmitting on. 2) I still would not want to use a 10m
dipole and transmit 100 watts on 80 without at least using a tuner. Am
I correct in these assumptions?



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Old November 27th 07, 05:54 PM posted to rec.radio.amateur.antenna
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Default using an MFJ-941E tuner on all bands?

I just read this article from ARRL:

http://www.arrl.org/tis/info/pdf/9312070.pdf

This is exactly what I want to do. Put up a single dipole that I can
use reasonably well on HF bands. The thing I haven't figured out yet
about ladder line yet is how to bring it in to the house.
My current setup is a 10m dipole with RG58 coax feed line shoved under
the back door. Obviously I can't do that with ladder line (aluminum
door). I think I might get away with drilling two holes in the wall
and putting in connectors, then attach the ladder line to the
connectors. On the other side of the wall.... would I still want to
use ladder line to continue on into the tuner? Or would would I want
to attach a coax at that point from the wall to the tuner? Or maybe I
need to hang my tuner on the wall. I'll google around and see
what other people are doing, but I'd like to hear some ideas if anyone
here is using ladder line. (should I change the topic for this
thread?)

Cecil, I love your no tuner ladder line idea. I think someday I'll try
that when I have more experience with feed lines and antennas.


jim



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Old November 27th 07, 05:57 PM posted to rec.radio.amateur.antenna
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Default using an MFJ-941E tuner on all bands?

On Tue, 27 Nov 2007 07:35:07 -0800 (PST), James barrett
wrote:

Hi, I don't understand how you can add elements to an existing antenna
and have it still work on the band it was originally made for. Do you
still need a tuner? Or do you remove the 20m elements to transmit on
10m?


Hi Jim,

Adding a new band's element will likely disturb the performance of an
existing one. However, it will be slight, and if you anticipate this,
you can construct a two band antenna and tune both. Similarly, you
can construct three, four, five.... band antennas using similar
principles. There is, of course, the compounding of difficulty as you
increase this count, but that doesn't preclude it being done
successfully.

73's
Richard Clark, KB7QHC
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Old November 27th 07, 06:04 PM posted to rec.radio.amateur.antenna
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Default using an MFJ-941E tuner on all bands?

On Tue, 27 Nov 2007 07:55:57 -0800 (PST), James barrett
wrote:

Why is the twin lead consideres less
lossy than coax?


Hi Jim,

All loss is in the bulk of the conductor. When comparing the two,
twin lead usually has more bulk = less loss.

I had thought that higher ohms meant higher impedance
and I thought higher impedance means higher loss. Obviously I have not
read the chapter on transmission lines yet ;-), so I may have that all
wrong.


You do. Impedance restricts energy, it doesn't consume it (loss).

Also, in the article, I liked the part about before 1950, no one even
heard about swr, and that antennas with high swr were working just
fine.


This is much the same illusion of climbing into a car with the
speedometer exclusive marked in kM/h and thinking it has great 0-60
acceleration. Everything is just fine (ignorance is bliss).

But I make 2 assumptions: 1) I'm thinking, even if they didn't
know or care about swr, they still had to cut their dipoles for the
band they were transmitting on.


You don't even have to do that now, much less before 1950. Resonance
merely simplifies things and gives you a benchmark for performance. If
you don't have resonance, you accommodate to re-achieve that benchmark
for performance (this is how it is done now, and how it was done
before 1950).

2) I still would not want to use a 10m
dipole and transmit 100 watts on 80 without at least using a tuner. Am
I correct in these assumptions?


That would be a pretty good intuition to proceed along. In this
specific case, you may even stand to lose power with the best of
tuners. Further correspondence will reveal those pitfalls.

73's
Richard Clark, KB7QHC
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Old November 27th 07, 06:13 PM posted to rec.radio.amateur.antenna
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Default using an MFJ-941E tuner on all bands?

On Tue, 27 Nov 2007 08:54:24 -0800 (PST), James barrett
wrote:

I think I might get away with drilling two holes in the wall
and putting in connectors, then attach the ladder line to the
connectors.


Hi Jim,

Good plan. Check to make sure you don't have foil backed insulation
in the walls that might provide a short circuit path.

On the other side of the wall.... would I still want to
use ladder line to continue on into the tuner?


You can do that.

Or would would I want
to attach a coax at that point from the wall to the tuner?


You can do that too, but it is not a matter of "wanting to."

Or maybe I
need to hang my tuner on the wall.


Only if you can reach it as part of your typical operating behavior.

73's
Richard Clark, KB7QHC
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Old November 27th 07, 06:28 PM posted to rec.radio.amateur.antenna
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Default using an MFJ-941E tuner on all bands?

On 2007-11-27, James barrett wrote:
I just read this article from ARRL:

http://www.arrl.org/tis/info/pdf/9312070.pdf

This is exactly what I want to do. Put up a single dipole that I can
use reasonably well on HF bands. The thing I haven't figured out yet
about ladder line yet is how to bring it in to the house.
My current setup is a 10m dipole with RG58 coax feed line shoved under
the back door. Obviously I can't do that with ladder line (aluminum
door). I think I might get away with drilling two holes in the wall
and putting in connectors, then attach the ladder line to the


Have the ladder line go to a ferrite bead balun (converts balanced to
unbalanced) and a short piece of coax into the house and directly to the
tuner. (Walt Maxwell's idea) I use this on my 80m loop and it tunes 80-10m
easily.

....Edwin
--
__________________________________________________ __________
"Once you have flown, you will walk the earth with your eyes
turned skyward, for there you have been, there you long to
return."-da Vinci http://bellsouthpwp2.net/e/d/edwinljohnson
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Old November 27th 07, 07:31 PM posted to rec.radio.amateur.antenna
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Default using an MFJ-941E tuner on all bands?

James barrett wrote:
I just read this article from ARRL:

http://www.arrl.org/tis/info/pdf/9312070.pdf

This is exactly what I want to do. Put up a single dipole that I can
use reasonably well on HF bands. The thing I haven't figured out yet
about ladder line yet is how to bring it in to the house.


Lots of ways. In my house, I made a hole below the window that I can
cover with a plate if I move. Some folks use Plexiglas for one of their
windows and drill holes and make jumpers. IIRC Cecil's web pages have a
nice illustration of that. You won't need as many holes if you make a
regular dipole of course.



My current setup is a 10m dipole with RG58 coax feed line shoved under
the back door. Obviously I can't do that with ladder line (aluminum
door). I think I might get away with drilling two holes in the wall
and putting in connectors, then attach the ladder line to the
connectors.


Yep, that will work.



On the other side of the wall.... would I still want to
use ladder line to continue on into the tuner? Or would would I want
to attach a coax at that point from the wall to the tuner?


Run the ladder line the whole way to the tuner. Some folks put a balun
in line and run coax for the last few feet, but the mfj has a balun
built in.


Or maybe I
need to hang my tuner on the wall.


heh, that would be good for excercising!



I'll google around and see
what other people are doing, but I'd like to hear some ideas if anyone
here is using ladder line. (should I change the topic for this
thread?)


Nah, it's pretty much still on topic.

One of the first things though is that there is ladder line, and there
is window line. Most of us use window line, although ladder line has
some advantages. Window line is easier to handle, and should work just
fine for you. It is the poly coated stuff with cut out windows in it-
hence the name.

Cecil, I love your no tuner ladder line idea. I think someday I'll try
that when I have more experience with feed lines and antennas.


My xyl won't let me put one of those in - says it's visually challenged.


- 73 de Mike N3LI -
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