Cecil Moore wrote:

zeno wrote:
seriously, though, if one needed a section of ladder line to really stay
put (say a section which gets nervously close to other naughty metal things
or wire, why couldn't you fabricate just that section out of copper tubing
and then go the rest of the way with wire? Are there impedance issues when
changing the wire thickness along the way?

I have used solid copper wire sliding inside copper tubing to achieve
an adjustable length transmission line for matching purposes.
--
73, Cecil http://www.qsl.net/w5dxp

-----= Posted via Newsfeeds.Com, Uncensored Usenet News =-----
http://www.newsfeeds.com - The #1 Newsgroup Service in the World!
-----== Over 100,000 Newsgroups - 19 Different Servers! =-----

That's interesting, so you find wire whose OD is just right for the ID of the
tubing and that makes a good enough connection and is adjustable. How much
adjustment were you after, inches or feet?

-Bill

zeno wrote:

Cecil Moore wrote:
I have used solid copper wire sliding inside copper tubing to achieve
an adjustable length transmission line for matching purposes.

That's interesting, so you find wire whose OD is just right for the ID of the
tubing and that makes a good enough connection and is adjustable. How much
adjustment were you after, inches or feet?

I just relied on skin effect to effect the proper conductive function. RF
won't flow into the inside of the tubing if it has any other "choice". :-)

The thing was adjustable from 20 feet to 35 feet in order to make a G5RV
truly a fully functional all-HF-band antenna. It really did work nearly
perfectly and could be automated using something like a screwdriver motor.
--
73, Cecil http://www.qsl.net/w5dxp



-----= Posted via Newsfeeds.Com, Uncensored Usenet News =-----
http://www.newsfeeds.com - The #1 Newsgroup Service in the World!
-----== Over 100,000 Newsgroups - 19 Different Servers! =-----

On Mon, 19 Apr 2004 00:10:50 GMT, zeno wrote:

Anyone just use lengths of copper pipe or tubing? You might only need a
tiny spacer every 5 feet or so. Was that you or someone else who made the
ladder line out of tubing shaped like a sine wave.... hi hi

seriously, though, if one needed a section of ladder line to really stay
put (say a section which gets nervously close to other naughty metal things
or wire, why couldn't you fabricate just that section out of copper tubing
and then go the rest of the way with wire? Are there impedance issues when
changing the wire thickness along the way?

73

Bill

Cecil Moore wrote:

zeno wrote:
I just found several hundered feet of used #10 solid copper, insulated
wire, it was pulled out of my well (submersible 240V pump) a few years
ago. Any reason, aside from weight, not to use this #10 wire for
constructing diy ladder-line?

Zeno, all of your suggestions would increase the weight of the
feedline, and possibly stretch the antenna. FYI, a 500-ft. spool of
#14 or #12 insulated, stranded copper wire from Lowe's Home
Improvement (or Home Depot) runs about $15.00

Bob
k5qwg



Maybe you should patent the idea of a self-supporting transmission line?
--
73, Cecil http://www.qsl.net/w5dxp

-----= Posted via Newsfeeds.Com, Uncensored Usenet News =-----
http://www.newsfeeds.com - The #1 Newsgroup Service in the World!
-----== Over 100,000 Newsgroups - 19 Different Servers! =-----

Bob Miller wrote:


Zeno, all of your suggestions would increase the weight of the
feedline, and possibly stretch the antenna. FYI, a 500-ft. spool of
#14 or #12 insulated, stranded copper wire from Lowe's Home
Improvement (or Home Depot) runs about $15.00

Bob
k5qwg

Hi Bob,

I did pick up a 500' roll of #12 insulated from the Home Depot here (current
price here is about $32), but it seems like this braided copper will require
too many spacers to keep it straight. I am thinking about returning it for some
solid copper #12. I think the solid will hold shape better as a ladder-line
with a minimum of spacers. Also I see no reason not to go with bare wire
instead of insulated.

Can anyone run down the pros and cons of bare vs. insulated for ladder-line. I
understand there is ever so slightly less loss with bare wire.


Bill

I tried practicing making some diy ladder line with a couple of
spacers and a variety of wi stranded #12, and solid #12, and
then solid #14 (all insulated).

I think I am going to pass on this process. The only way I can see
this homebrew ladder line holding its shape (spacing configuration)
is to keep it under quite a bit of tension, a situation which may
not actually be appropriate to my specific installation parameters
here.

I am now thinking: how bad could those commercially manufactured
window lines be?

Any recommendations on a specific type of commercially made window
(ladder) line? I see that it comes in a variety of configurations
and slight differences in Z.

This feed line will be for a full wave 160m loop.

I am not all that convinced that the effects of weather on this
commercially available balanced line would be that much more
negative than what it would be with any homebrew line I could
construct.

I am under the impression that homebrewed ladder line should strive
to have as few spacers as possible, eg. 3' for straight runs, 1-2'
for curves. Using these guidelines it seems like what I would come
up with would not maintain a precise spacing and the temptation
would be to use a spacer at every foot. Wouldn't it be undesireable
to use so many spacers?

Somebody out there must like commercial window ladder line?

Bill

'Doc wrote:

Larry,
Boy, are you gonna have fun! As Cecil said, spacing isn't
all that critical. Use whatever you can find enough of, to make
the 'spreaders', as long as it's not conductive it should work.
The simplest way to feed ladder line through a window is to
make a 'spacer' board to fit in the window. Drill a couple of
holes in the board, the correct distance apart, feed the line
through the holes, 'hot glue' in place (or however you can get
it to stay put. Have to remove the screen...
'Doc

PS - The real 'trick' is to keep the line from 'swarming' on
you when you finish.

How close do the spacers need to be placed in reality?

http://www.w7fg.com/ant.htm

How close do these spacers appear to be.

Bill

zeno wrote:

I tried practicing making some diy ladder line with a couple of
spacers and a variety of wi stranded #12, and solid #12, and
then solid #14 (all insulated).

I think I am going to pass on this process. The only way I can see
this homebrew ladder line holding its shape (spacing configuration)
is to keep it under quite a bit of tension, a situation which may
not actually be appropriate to my specific installation parameters
here.

I am now thinking: how bad could those commercially manufactured
window lines be?

Any recommendations on a specific type of commercially made window
(ladder) line? I see that it comes in a variety of configurations
and slight differences in Z.

This feed line will be for a full wave 160m loop.

I am not all that convinced that the effects of weather on this
commercially available balanced line would be that much more
negative than what it would be with any homebrew line I could
construct.

I am under the impression that homebrewed ladder line should strive
to have as few spacers as possible, eg. 3' for straight runs, 1-2'
for curves. Using these guidelines it seems like what I would come
up with would not maintain a precise spacing and the temptation
would be to use a spacer at every foot. Wouldn't it be undesireable
to use so many spacers?

Somebody out there must like commercial window ladder line?

Bill

'Doc wrote:

Larry,
Boy, are you gonna have fun! As Cecil said, spacing isn't
all that critical. Use whatever you can find enough of, to make
the 'spreaders', as long as it's not conductive it should work.
The simplest way to feed ladder line through a window is to
make a 'spacer' board to fit in the window. Drill a couple of
holes in the board, the correct distance apart, feed the line
through the holes, 'hot glue' in place (or however you can get
it to stay put. Have to remove the screen...
'Doc

PS - The real 'trick' is to keep the line from 'swarming' on
you when you finish.

On Tue, 20 Apr 2004 06:23:13 GMT, zeno wrote:

Any recommendations on a specific type of commercially made window
(ladder) line? I see that it comes in a variety of configurations
and slight differences in Z.

This feed line will be for a full wave 160m loop.

Hi Bill,

You repeatedly characterize this as 160M and given the size and height
- Why do you think you need ladder line when it will in all
probability fit quite nicely into a coax?

In free space, it may show as much as 140 Ohms R; however, within the
cold embrace of earth only 50 feet away, you will barely muster 35
Ohms at resonance.

73's
Richard Clark, KB7QHC

zeno wrote:
Any recommendations on a specific type of commercially made window
(ladder) line? I see that it comes in a variety of configurations
and slight differences in Z.

I use Wireman #554, #14, stranded, copper-clad steel. It's
virtually indestructible. http://www.thewireman.com
--
73, Cecil http://www.qsl.net/w5dxp



-----= Posted via Newsfeeds.Com, Uncensored Usenet News =-----
http://www.newsfeeds.com - The #1 Newsgroup Service in the World!
-----== Over 100,000 Newsgroups - 19 Different Servers! =-----

zeno wrote:
http://www.w7fg.com/ant.htm

How close do these spacers appear to be.

Using a tape measure, they appear to be 21 inches apart.
--
73, Cecil http://www.qsl.net/w5dxp



-----= Posted via Newsfeeds.Com, Uncensored Usenet News =-----
http://www.newsfeeds.com - The #1 Newsgroup Service in the World!
-----== Over 100,000 Newsgroups - 19 Different Servers! =-----

zeno wrote:

I tried practicing making some diy ladder line...

I am now thinking: how bad could those commercially manufactured
window lines be?

Any recommendations on a specific type of commercially made window
(ladder) line?

I used 300 ohm TV twin lead for years. Why the concern about 600 ohms? It
really doesn't matter unless you have a 600 Ohm feedpoint. The losses are
still very low regardless of conditions, and as for dirty or rain, I had
some up from 1983 to 1996 -- and never noticed any changes. When I took
the antenna down the twinlead was as good as new and I used it for other
things.

Irv VE6BP

--
--------------------------------------
Diagnosed Type II Diabetes March 5 2001
Beating it with diet and exercise!
297/215/210 (to be revised lower)
58"/43"(!)/44" (already lower too!)
--------------------------------------
Visit my HomePage at http://members.shaw.ca/finkirv/
Visit my Baby Sofia website at http://members.shaw.ca/finkirv4/
Visit my OLDTIMERS website at http://members.shaw.ca/finkirv5/
--------------------
Irv Finkleman,
Grampa/Ex-Navy/Old Fart/Ham Radio VE6BP
Calgary, Alberta, Canada