Thank you,

Is this the same program he http://www.qsl.net/w5dxp/notuner.htm ?

I have been looking at this awhile and wonder if the SWR on 17 and 10
meters can be better tuned by adding an additional 1/2 foot section.

It probably doesn't matter at that SWR.


another question related to the antenna:

Do you think this would work? Instead of switching the lead in and
out, could the leads be tapped at each band according to the matched
setting? So that instead of a series of knife switches, a double-pole
multi-throw switch could be used to select a band or frequency for
use?

Thanks again, gears are turning in my head again...


73 for now
Buck





On Wed, 8 Jun 2005 11:40:10 -0400, "Fred W4JLE"
wrote:

I can send you a copy of a program I wrote. It is based on Cecil's work. You
can put in the length of the dipole you want to use, the frequency, and type
of feed line. It gives you the choice of giving you the length of feedline
for that single case, or a start and stop frequency in which case it prints
out a chart of frequency vs. total length.Add jumpers to make up the
difference above 80 feet and your good to go!

For portable operation a 130 foot dipole fed with 80 feet of 300 Ohm to a
small piece of Plexiglas and two sets of banana jacks would allow you to
put jumpers of various lengths into the jacks. The second set goes to the
rig via a convenient length of 50 ohm coax with a choke balun of ferrites.
Lengths of 1,2,4, and 8 foot would allow you to make up jumpers to enable 75
meters from 3.8 to 4 and all the other bands with the exception of 60
meters.

It can be made smaller if your only interested in 40 and up etc. Easy to
carry, no tuner and worst swr around 1.7:1

For example a 2 foot jumper would put you at 4.0, and a series of an 8,2,
and 1 jumper for 3.8

--
73 for now
Buck
N4PGW

On Wed, 08 Jun 2005 12:52:01 -0400, Buck wrote:

Pardon me while I learn from this discussion.

Hold on Buck.

So far there has been very little "learning" to be done from this
discussion.

I dislike getting personal but I strongly suggest that you reject
anything Fred has put forth. Some of what he says is correct, but for
the most part you are being led astray. Since you don't yet have the
skills to separate the good from the BS, the safest thing to do is
ignore it all.

For example he has suggested that an all-band antenna can be nothing
more than a 130' dipole fed through 100' of 450 ohm line to which you
connect a 50 ohm coax and "your rig will be happy."

Let's examine this premise, shall we.

If you don't already have it, download the free version of EZNEC.

www.eznec.com

If you have MS Excel do the following. If you don't skip down below
the dotted line.

Download the program XLZIZL.xls at:

http://www.qsl.net/ac6la/xlzizl.html

Using EZNEC set up a frequency sweep, for example 3.5 to 4.0 MHz in 50
KHz steps and check Microsmith Files as an output and give a file name
("80meter" for example)

"Build" the 130' long antenna in the wires menu, add a source in the
middle and do the frequency sweep. (I used a height of 50' and 12 AWG
wire)

Open xlzizl.xls and select the "ZIZL" worksheet if it isn't already
active. "Press" the "Clear all freq..." button (near cell A25).
Press the "Read file for Freq, R, X" button (near cell D25). Navigate
to the file location where you specified the Microsmith files be
located. The default is in the Smith subdirectory in the EZW
directory. Select the file "80meter.gam" and open it.

The calculated data will populate the Frequency, R at load and X at
load cells.

Press the "Refresh and show Smith" button (near cell I28). The Smith
chart will open and display the calculated impedance data for the 130'
antenna operated from 3.5 to 4.0 MHz.

Now we are going to add a transmission line. Select the "ZIZL"
worksheet again and press the "Set via Dialog" button (near cell A34).

The "Network definition" window will open with "Element position 1"
selected by default. Change it to "5". Under "Element type" select
Transmission line.

Under "Qualifier" scroll the dropdown menu to either "Generic 450 ohm
window" or if you more more realistic numbers you can select one of
the Wireman Ladder line types. (Ignore "wet" ones.)

Mouse down to the "Element Value" area an type in "100" for the length
and press the "Set This Element" button and then close the Network
definition window.

Press the Refresh and show Smith Chart button and you will now see two
traces, the original "load" data and the feedpoint data at the input
to the 100' transmission line. If you know anything about Smith charts
you will immediately notice that the match is worse at the input of
the line than it was at the antenna. So much for the "magic" 100'
length that Fred proposes.

Going back to the ZIZL sheet and looking in the "results" area you can
see that at 3.5 MHz the SWR is 36:1. Without the "magic" 100' of
ladderline, the SWR is 3:1.

You can repeat this exercise at different frequency ranges and see
just how awful this idea is.

Let's continue...

Assume that your 50-ohm coax is 50' long. Go back to the Network "Set
via Dialog" button. Accept the "1" default for Element Position and
again select Transmission Line for Element Type. For Qualifier, let's
use Belden 9258 (RG8X), although you can use what you use.

Set the length to 50' and press "Set this Element." Close the window.

Press the Refresh and show Smith button and you will now see three
traces on the chart: the load, the impedance at the inut of the 450
ohm line and the impedance at the input of the 50 ohm line.

Return to the ZIZL sheet and under results note that the SWR at 3.5
MHz is down to "only" 17:1. This is what your rig is going to see.
Also note that the network loss (the line loss) is over 3 dB.

Now just for giggles, let's take out the 100' of ladderline and make
the whole 150' run out of RG8X. You can just highlight the cells "G34
through G36" and delete them and then select cell C36 and type in 150
and tab out. Press "F9" and see the new results.

The 3.5 MHz SWR is now 2.4:1 and the total network (line) loss is 1.2
dB. So replacing the "low loss" ladderline with "lossy" coax improved
the match and lowered the loss.

I don't know how much of this "magic" I can stand.

************************************************** *****************


If you don't have Excel there is a more labor intensive method that is
just as accurate.

Go to

http://www.qsl.net/ac6la/tldetails.html

and download the program and open it.

Select a transmission line type, "Generic 450 ohm Window" for example.
The line parameters will populate the boxes to the right. Under Set
Frequency, type in 3.5.

Run EZNEC one frequency at a time, beginning with 3.5 MHz. Look at
the source data and note the Impedance R and X values. Pay attention
to the sign of X.

Copy these values to "R" and "X" in the TLdetails program. Remember
the sign of X. For example I used R = 61, X = -64.

In the "results" area under "At Input" you can see the R and X values
at the input and note that the SWR in the 450 ohm line is about 7:1
and in the 50 ohm feeder Fred would have you connecting at this point
the SWR is as before ~36:1.

If you want to "add" the 50 ohm line, copy down the R and X at the
input (132, -470) and enter them in the the R and X boxes above.
Change the line type to Belden 9258 and the length to 50 feet and as
above, the SWR at the input is ~17:1.

To summarize:

There are ample free tools to work these problems out without relying
on bafflegab. You don't have to take my word or anyone else's; work
the problem yourself and learn something while doing it.

On Wed, 08 Jun 2005 12:23:50 -0700, Wes Stewart
wrote:
[snip}

Under "Qualifier" scroll the dropdown menu to either "Generic 450 ohm
window" or if you more more realistic numbers you can select one of
the Wireman Ladder line types. (Ignore "wet" ones.)

This should of course read, "...if you want more realistic..."

Bob Miller wrote:
Fred, any hints on winding your 450-ohm line around the wood dowels? I
have a feedline I wouldn't mind lengthening if I could do it without
loose ladderline everywhere.

You can string a straight piece of nylon/dacron rope from
one point to another and spiral the ladder-line using the
rope for support. Black tie wraps keep the ladder-line in
position. Another idea is to hang the ladder-line, accordion
style, under the eaves of your house.
--
73, Cecil http://www.qsl.net/w5dxp

----== Posted via Newsfeeds.Com - Unlimited-Uncensored-Secure Usenet News==----
http://www.newsfeeds.com The #1 Newsgroup Service in the World! 120,000+ Newsgroups
----= East and West-Coast Server Farms - Total Privacy via Encryption =----

Fred W4JLE wrote:
I can send you a copy of a program I wrote. It is based on Cecil's work. You
can put in the length of the dipole you want to use, the frequency, and type
of feed line.

That EXCEL program is nice. "imax.exe" is also available from my web
page. It was written in Quickbasic and executes in a DOS window.
--
73, Cecil http://www.qsl.net/w5dxp

----== Posted via Newsfeeds.Com - Unlimited-Uncensored-Secure Usenet News==----
http://www.newsfeeds.com The #1 Newsgroup Service in the World! 120,000+ Newsgroups
----= East and West-Coast Server Farms - Total Privacy via Encryption =----

Buck wrote:
I know I'll be corrected if I am wrong, but if I am correct, the SWR
is high (actually varies by band) on the feedline for the G5RV. The
twin lead portion doesn't have the losses the coax does with that SWR
so more of the signal gets to the antenna than it would if it were
just coax going to a twenty meter dipole.

Here are the 50 ohm SWRs at the 300 ohm twinlead to 50 ohm
coax junction that EZNEC produced in 2001 for a 102' dipole
at 40 feet fed with 27.7' of 300 ohm ladder-line.

3.8 MHz 3.2:1, 7.2 MHz 3.6:1, 10.125 MHz 56:1, 14.2 MHz 4.1
18.14 MHz 37:1, 21.3 MHz 11:1, 24.95 MHz 7.6:1, 28.4 MHz 66:1

The G5RV was designed for 80m, 40m, & 20m operation and on
those designed-for bands does a reasonable job. It works
pretty well on 12m. Less well on 15m. Terrible for 30m, 17m,
and 10m operation.

However, if you are willing to vary the length of the 300 ohm
(or 450 ohm) matching section, you can achieve a reasonable
match on any HF band.
--
73, Cecil http://www.qsl.net/w5dxp

----== Posted via Newsfeeds.Com - Unlimited-Uncensored-Secure Usenet News==----
http://www.newsfeeds.com The #1 Newsgroup Service in the World! 120,000+ Newsgroups
----= East and West-Coast Server Farms - Total Privacy via Encryption =----

Buck wrote:

Cecil Moore wrote:
Fred is using my design from:
http://www.qsl.net/w5dxp/notuner.htm

Can the 17 and 10 meter bands be tuned to a better match or are they
compromised so the antenna doesn't need additional matching sections?

Each installation will vary depending upon the surroundings. My 50
ohm SWR on 17m was 1.6:1 and 1.7:1 on 10m. Those were acceptable
to my IC-706 at the time - even more acceptable to me now that I
have an IC-756PRO with its internal tuner. :-)

In fact, one of the advantages/benefits of this matching method is
that it allows internal tuners to achieve perfect matches on all
HF bands - no external tuner necessary.
--
73, Cecil http://www.qsl.net/w5dxp

----== Posted via Newsfeeds.Com - Unlimited-Uncensored-Secure Usenet News==----
http://www.newsfeeds.com The #1 Newsgroup Service in the World! 120,000+ Newsgroups
----= East and West-Coast Server Farms - Total Privacy via Encryption =----

Buck wrote:
Pardon me while I learn from this discussion.

The 450 ohm antenna is designed to be tuned by using exactly 1/2
electrical wave lengths to match both the transmitter and antenna.
This should mean that any differing feedline should work equally as
well (except for the losses) if I am correct....

What you are missing is that first piece of matching section
which can be any length less than 1/2WL. After that first
piece of matching section, you could indeed switch to a
different characteristic impedance. Congratulations, you
have just invented the G5RV. :-)
--
73, Cecil http://www.qsl.net/w5dxp

----== Posted via Newsfeeds.Com - Unlimited-Uncensored-Secure Usenet News==----
http://www.newsfeeds.com The #1 Newsgroup Service in the World! 120,000+ Newsgroups
----= East and West-Coast Server Farms - Total Privacy via Encryption =----

Buck wrote:
Do you think this would work? Instead of switching the lead in and
out, could the leads be tapped at each band according to the matched
setting? So that instead of a series of knife switches, a double-pole
multi-throw switch could be used to select a band or frequency for
use?

Nope, that won't work because it leaves unterminated stubs
in the transmission line system. You might be able to
predict their effect but I have never tried to do that.
It's rather like a bag of worms.
--
73, Cecil http://www.qsl.net/w5dxp

----== Posted via Newsfeeds.Com - Unlimited-Uncensored-Secure Usenet News==----
http://www.newsfeeds.com The #1 Newsgroup Service in the World! 120,000+ Newsgroups
----= East and West-Coast Server Farms - Total Privacy via Encryption =----

This is what I use Buck. Mine is a 132 foot dipole and I insert the lengths
with Omron 4PDT relays controlled by 2 decimal thumbwheel switches.

I just added another relay that ties the two sides of the twinlead together
and feeds the center conductor of the coax. I plan to use it on 160. I have
not tested it yet because conditions have been so bad with storms every day
this week.


"Buck" wrote in message
...

Thank you,

Is this the same program he http://www.qsl.net/w5dxp/notuner.htm ?

I have been looking at this awhile and wonder if the SWR on 17 and 10
meters can be better tuned by adding an additional 1/2 foot section.

It probably doesn't matter at that SWR.


another question related to the antenna:

Do you think this would work? Instead of switching the lead in and
out, could the leads be tapped at each band according to the matched
setting? So that instead of a series of knife switches, a double-pole
multi-throw switch could be used to select a band or frequency for
use?

Thanks again, gears are turning in my head again...


73 for now
Buck





On Wed, 8 Jun 2005 11:40:10 -0400, "Fred W4JLE"
wrote:

I can send you a copy of a program I wrote. It is based on Cecil's work.
You
can put in the length of the dipole you want to use, the frequency, and
type
of feed line. It gives you the choice of giving you the length of
feedline
for that single case, or a start and stop frequency in which case it
prints
out a chart of frequency vs. total length.Add jumpers to make up the
difference above 80 feet and your good to go!

For portable operation a 130 foot dipole fed with 80 feet of 300 Ohm to a
small piece of Plexiglas and two sets of banana jacks would allow you to
put jumpers of various lengths into the jacks. The second set goes to the
rig via a convenient length of 50 ohm coax with a choke balun of
ferrites.
Lengths of 1,2,4, and 8 foot would allow you to make up jumpers to enable
75
meters from 3.8 to 4 and all the other bands with the exception of 60
meters.

It can be made smaller if your only interested in 40 and up etc. Easy to
carry, no tuner and worst swr around 1.7:1

For example a 2 foot jumper would put you at 4.0, and a series of an 8,2,
and 1 jumper for 3.8

--
73 for now
Buck
N4PGW