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On Aug 12, 2020, at 16:37, David Eckhardt <davearea51a@...> wrote:

锘縉ot quite correct! Ladder line is a transmission line just like coaxial
line. However, they perform their function differently.

1) The center fed dipole is a balanced source/load - differential
source/load.

2) Ladder line is a balanced transmission line - differential
transmission line. It is the correct transmission line to connect directly
to a balanced/differential source/load (dipole). It does NOT participate
in radiation. As a transmission line, fields close onto themselves
(between the two parallel conductors) and do not open onto free space, so
no radiation occurs.

3) Coax is an unbalanced transmission line - common mode transmission
line. Fields are intended to close between the inner conductor and the
inside of the outer shield/braid. It is NOT the correct transmission line
to connect directly to a balanced/differential source/load (dipole).

4) If coaxial cable it is connected directly to a dipole, the outer
portion of the shield/braid WILL participate in radiation and gather noise
on receive that will couple into the antenna and receiver.

5) The correct manner in which to connect a coaxial transmission line
(unbalanced transmission line) to a dipole (balanced source/load) is
through a 1:1 current balun or common mode choke. This will prevent the
outer layer of the coaxial braid from participating in radiation and
coupling local noise into the antenna/receiver.

6) 4:1, 2:1, 9:1,.......are NOT appropriate for the purpose stated in
(5). These are TRANSFORMERS and NOT BALUNS.

7) If you MUST use a transformer for impedance transformation, follow it
with a 1:1 current balun or common mode choke.

Dave - W脴LEV

On Wed, Aug 12, 2020 at 9:20 PM Darrell Carothers <rescuemedic1@...>
wrote:

I am slowly getting parts in to try my end fed long wire antenna. Correct
me if I am wrong. With a center fed dipole, the 300 or 450 ohm ladder line
feeding it is part of the antenna. I would think I would use my NanoVNA at
the end of the feed to check where it would be resonant and for SWR. If so,
would the coax feeding the end fed long wire antenna also be considered
part of the antenna and use the NanoVNA to measure accordingly? I am told
this doesn鈥檛 need a counterpoise.

Am I correct or am I missing something?

Thanks
Darrell
N5FTW



Sent from my over-rated IPhone 7 Plus. Any Mis-spellings or grammar
errors are due to my IPhone auto correct feature.

--
*Dave - W脴LEV*
*Just Let Darwin Work*

On Aug 12, 2020, at 16:59, David Eckhardt <davearea51a@...> wrote:

锘緼s far as a counterpoise goes: As a single-ended, common mode source/load,
the fields must go somewhere. They don't just abruptly stop at the feed of
the EFHW (end fed half wave). Yes, the coaxial feed WILL participate in
radiation as it forms the counterpoise to the EFHW. Some form of
decoupling must be supplied before it connects to the radio or matching
network (a.k.a., 'antenna "tuner"') or there will be "RF In the Shack". A
current choke or common mode choke installed before the coax connects to
the radio or matching network would be appropriate. Then you can connect
the VNA to that point AFTER the current balun or common mode choke.
Without that, the VNA and anything holding onto the VNA or capacitively
coupled to the VNA will become part of what you measure and part of the
antenna.

Dave - W脴LEV

On Wed, Aug 12, 2020 at 9:37 PM David Eckhardt via groups.io <davearea51a=
[email protected]> wrote:

Not quite correct! Ladder line is a transmission line just like coaxial
line. However, they perform their function differently.

1) The center fed dipole is a balanced source/load - differential
source/load.

2) Ladder line is a balanced transmission line - differential
transmission line. It is the correct transmission line to connect directly
to a balanced/differential source/load (dipole). It does NOT participate
in radiation. As a transmission line, fields close onto themselves
(between the two parallel conductors) and do not open onto free space, so
no radiation occurs.

3) Coax is an unbalanced transmission line - common mode transmission
line. Fields are intended to close between the inner conductor and the
inside of the outer shield/braid. It is NOT the correct transmission line
to connect directly to a balanced/differential source/load (dipole).

4) If coaxial cable it is connected directly to a dipole, the outer
portion of the shield/braid WILL participate in radiation and gather noise
on receive that will couple into the antenna and receiver.

5) The correct manner in which to connect a coaxial transmission line
(unbalanced transmission line) to a dipole (balanced source/load) is
through a 1:1 current balun or common mode choke. This will prevent the
outer layer of the coaxial braid from participating in radiation and
coupling local noise into the antenna/receiver.

6) 4:1, 2:1, 9:1,.......are NOT appropriate for the purpose stated in
(5). These are TRANSFORMERS and NOT BALUNS.

7) If you MUST use a transformer for impedance transformation, follow it
with a 1:1 current balun or common mode choke.

Dave - W脴LEV

On Wed, Aug 12, 2020 at 9:20 PM Darrell Carothers <rescuemedic1@...>
wrote:

I am slowly getting parts in to try my end fed long wire antenna. Correct
me if I am wrong. With a center fed dipole, the 300 or 450 ohm ladder

line

feeding it is part of the antenna. I would think I would use my NanoVNA

at

the end of the feed to check where it would be resonant and for SWR. If

so,

would the coax feeding the end fed long wire antenna also be considered
part of the antenna and use the NanoVNA to measure accordingly? I am told
this doesn鈥檛 need a counterpoise.

Am I correct or am I missing something?

Thanks
Darrell
N5FTW



Sent from my over-rated IPhone 7 Plus. Any Mis-spellings or grammar
errors are due to my IPhone auto correct feature.

--
*Dave - W脴LEV*
*Just Let Darwin Work*

--
*Dave - W脴LEV*
*Just Let Darwin Work*

On Aug 12, 2020, at 17:05, David Eckhardt <davearea51a@...> wrote:

锘縔ou are most concerned with the impedance the end of the coax presents to
your matching network/radio. Therefore, you should measure at the shack
end of the coax. Calibrate the VNA as a stand-alone instrument. Once
calibrated, connect it to the shack end of the coax and make your
measurements.

Remember, the native VNA without using Saver supported on a PC has only 101
points. Measuring from 2 to 30 MHz is not appropriate as it will yield a
measurement poist every 0.3 MHz, not good for looking for narrow
resonances. So, either make the measurements in small increments across
the HF bands or use NANOVNA Saver supported on a PC or laptop which offers
up to 1024 measurement points (and cal points).

Dave - W脴LEV

Dave - W脴LEV

On Wed, Aug 12, 2020 at 9:57 PM Darrell Carothers <rescuemedic1@...>
wrote:

It is my understanding that this Matchbox is a 9:1. The system gets good
reviews on 80-10m. So if I am using this system, would I need to calibrate
the NanoVNA using the coax, then get my measurements from the antenna or
calibrate the NanoVNA as normal and get measurements from the entire
system? I appreciate your detailed explanation.

Darrell

Sent from my over-rated IPhone 7 Plus. Any Mis-spellings or grammar
errors are due to my IPhone auto correct feature.

On Aug 12, 2020, at 16:37, David Eckhardt <davearea51a@...> wrote:

锘縉ot quite correct! Ladder line is a transmission line just like coaxial
line. However, they perform their function differently.

1) The center fed dipole is a balanced source/load - differential
source/load.

2) Ladder line is a balanced transmission line - differential
transmission line. It is the correct transmission line to connect

directly

to a balanced/differential source/load (dipole). It does NOT participate
in radiation. As a transmission line, fields close onto themselves
(between the two parallel conductors) and do not open onto free space, so
no radiation occurs.

3) Coax is an unbalanced transmission line - common mode transmission
line. Fields are intended to close between the inner conductor and the
inside of the outer shield/braid. It is NOT the correct transmission

line

to connect directly to a balanced/differential source/load (dipole).

4) If coaxial cable it is connected directly to a dipole, the outer
portion of the shield/braid WILL participate in radiation and gather

noise

on receive that will couple into the antenna and receiver.

5) The correct manner in which to connect a coaxial transmission line
(unbalanced transmission line) to a dipole (balanced source/load) is
through a 1:1 current balun or common mode choke. This will prevent the
outer layer of the coaxial braid from participating in radiation and
coupling local noise into the antenna/receiver.

6) 4:1, 2:1, 9:1,.......are NOT appropriate for the purpose stated in
(5). These are TRANSFORMERS and NOT BALUNS.

7) If you MUST use a transformer for impedance transformation, follow it
with a 1:1 current balun or common mode choke.

Dave - W脴LEV

On Wed, Aug 12, 2020 at 9:20 PM Darrell Carothers <

rescuemedic1@...>

wrote:

I am slowly getting parts in to try my end fed long wire antenna.

Correct

me if I am wrong. With a center fed dipole, the 300 or 450 ohm ladder

line

feeding it is part of the antenna. I would think I would use my NanoVNA

at

the end of the feed to check where it would be resonant and for SWR. If

so,

would the coax feeding the end fed long wire antenna also be considered
part of the antenna and use the NanoVNA to measure accordingly? I am

told

this doesn鈥檛 need a counterpoise.

Am I correct or am I missing something?

Thanks
Darrell
N5FTW



Sent from my over-rated IPhone 7 Plus. Any Mis-spellings or grammar
errors are due to my IPhone auto correct feature.

--
*Dave - W脴LEV*
*Just Let Darwin Work*

--
*Dave - W脴LEV*
*Just Let Darwin Work*

On Aug 12, 2020, at 17:06, Jerry Gaffke via groups.io <jgaffke@...> wrote:

锘緿ave is right about this:

5) The correct manner in which to connect a coaxial transmission line
(unbalanced transmission line) to a dipole (balanced source/load) is
through a 1:1 current balun or common mode choke. This will prevent the
outer layer of the coaxial braid from participating in radiation and
coupling local noise into the antenna/receiver.

Many hams do simple tie their 50 or 75 ohm coax directly into the center-fed dipole.
Often that works just fine, so OK to just flip something up and try
the baluns and chokes later.

An end fed half-wave antenna (or multiples thereof) has a high impedance feed,
up around 3000 ohms. So requires a matching network to go from 50 ohm coax to high impedance.
Since the feed into the antenna is high impedance, not much of a counterpoise is needed.
The coax from transmitter into the matching network usually suffices.
Here's a good place to ask questions:


I'm not aware of what you can get away with when feeding an end-fed half-wave with ladder line.
Most such systems use coax.

An end fed long wire is pot luck. How long it is determines the impedance at any given frequency,
how much it will need a counterpoise, and the requirements of the matching network.
There are specific recipes for this that some hams have found to work great on multiple bands.
It usually does require a significant counterpoise.

Jerry, KE7ER

On Wed, Aug 12, 2020 at 02:37 PM, David Eckhardt wrote:


Not quite correct! Ladder line is a transmission line just like coaxial
line. However, they perform their function differently.

1) The center fed dipole is a balanced source/load - differential
source/load.

2) Ladder line is a balanced transmission line - differential
transmission line. It is the correct transmission line to connect directly
to a balanced/differential source/load (dipole). It does NOT participate
in radiation. As a transmission line, fields close onto themselves
(between the two parallel conductors) and do not open onto free space, so
no radiation occurs.

3) Coax is an unbalanced transmission line - common mode transmission
line. Fields are intended to close between the inner conductor and the
inside of the outer shield/braid. It is NOT the correct transmission line
to connect directly to a balanced/differential source/load (dipole).

4) If coaxial cable it is connected directly to a dipole, the outer
portion of the shield/braid WILL participate in radiation and gather noise
on receive that will couple into the antenna and receiver.

5) The correct manner in which to connect a coaxial transmission line
(unbalanced transmission line) to a dipole (balanced source/load) is
through a 1:1 current balun or common mode choke. This will prevent the
outer layer of the coaxial braid from participating in radiation and
coupling local noise into the antenna/receiver.

6) 4:1, 2:1, 9:1,.......are NOT appropriate for the purpose stated in
(5). These are TRANSFORMERS and NOT BALUNS.

7) If you MUST use a transformer for impedance transformation, follow it
with a 1:1 current balun or common mode choke.

Dave - W脴LEV

Thank you. Excuse my beginner questions but it seems I have a lot to learn. I will be using a auto tuner. I was just trying to find out what my SWR would be on the different bands and where it would be resonant on each band so I could attempt to find out if I need to trim it to tune it a bit. I guess I need to do more research before I attempt to put it in service.

Darrell

Sent from my over-rated IPhone 7 Plus. Any Mis-spellings or grammar errors are due to my IPhone auto correct feature.

On Aug 12, 2020, at 16:59, David Eckhardt <davearea51a@...> wrote:

锘緼s far as a counterpoise goes: As a single-ended, common mode source/load,
the fields must go somewhere. They don't just abruptly stop at the feed of
the EFHW (end fed half wave). Yes, the coaxial feed WILL participate in
radiation as it forms the counterpoise to the EFHW. Some form of
decoupling must be supplied before it connects to the radio or matching
network (a.k.a., 'antenna "tuner"') or there will be "RF In the Shack". A
current choke or common mode choke installed before the coax connects to
the radio or matching network would be appropriate. Then you can connect
the VNA to that point AFTER the current balun or common mode choke.
Without that, the VNA and anything holding onto the VNA or capacitively
coupled to the VNA will become part of what you measure and part of the
antenna.

Dave - W脴LEV

On Wed, Aug 12, 2020 at 9:37 PM David Eckhardt via groups.io <davearea51a=
[email protected]> wrote:

Not quite correct! Ladder line is a transmission line just like coaxial
line. However, they perform their function differently.

1) The center fed dipole is a balanced source/load - differential
source/load.

2) Ladder line is a balanced transmission line - differential
transmission line. It is the correct transmission line to connect directly
to a balanced/differential source/load (dipole). It does NOT participate
in radiation. As a transmission line, fields close onto themselves
(between the two parallel conductors) and do not open onto free space, so
no radiation occurs.

3) Coax is an unbalanced transmission line - common mode transmission
line. Fields are intended to close between the inner conductor and the
inside of the outer shield/braid. It is NOT the correct transmission line
to connect directly to a balanced/differential source/load (dipole).

4) If coaxial cable it is connected directly to a dipole, the outer
portion of the shield/braid WILL participate in radiation and gather noise
on receive that will couple into the antenna and receiver.

5) The correct manner in which to connect a coaxial transmission line
(unbalanced transmission line) to a dipole (balanced source/load) is
through a 1:1 current balun or common mode choke. This will prevent the
outer layer of the coaxial braid from participating in radiation and
coupling local noise into the antenna/receiver.

6) 4:1, 2:1, 9:1,.......are NOT appropriate for the purpose stated in
(5). These are TRANSFORMERS and NOT BALUNS.

7) If you MUST use a transformer for impedance transformation, follow it
with a 1:1 current balun or common mode choke.

Dave - W脴LEV

On Wed, Aug 12, 2020 at 9:20 PM Darrell Carothers <rescuemedic1@...>
wrote:

I am slowly getting parts in to try my end fed long wire antenna. Correct
me if I am wrong. With a center fed dipole, the 300 or 450 ohm ladder

line

feeding it is part of the antenna. I would think I would use my NanoVNA

at

the end of the feed to check where it would be resonant and for SWR. If

so,

would the coax feeding the end fed long wire antenna also be considered
part of the antenna and use the NanoVNA to measure accordingly? I am told
this doesn鈥檛 need a counterpoise.

Am I correct or am I missing something?

Thanks
Darrell
N5FTW



Sent from my over-rated IPhone 7 Plus. Any Mis-spellings or grammar
errors are due to my IPhone auto correct feature.

--
*Dave - W脴LEV*
*Just Let Darwin Work*

--
*Dave - W脴LEV*
*Just Let Darwin Work*

Thank you. Excuse my beginner questions but it seems I have a lot to learn. I will be using a auto tuner. I was just trying to find out what my SWR would be on the different bands and where it would be resonant on each band so I could attempt to find out if I need to trim it to tune it a bit. I guess I need to do more research before I attempt to put it in service.

Darrell

Sent from my over-rated IPhone 7 Plus.聽 Any Mis-spellings or grammar errors are due to my IPhone auto correct feature.

On Aug 12, 2020, at 16:59, David Eckhardt <davearea51a@...> wrote:

锘緼s far as a counterpoise goes:聽 As a single-ended, common mode source/load,
the fields must go somewhere.聽 They don't just abruptly stop at the feed of
the EFHW (end fed half wave).聽 Yes, the coaxial feed WILL participate in
radiation as it forms the counterpoise to the EFHW.聽 Some form of
decoupling must be supplied before it connects to the radio or matching
network (a.k.a., 'antenna "tuner"') or there will be "RF In the Shack".聽 A
current choke or common mode choke installed before the coax connects to
the radio or matching network would be appropriate.聽 Then you can connect
the VNA to that point AFTER the current balun or common mode choke.
Without that, the VNA and anything holding onto the VNA or capacitively
coupled to the VNA will become part of what you measure and part of the
antenna.

Dave - W脴LEV

On Wed, Aug 12, 2020 at 9:37 PM David Eckhardt via groups.io <davearea51a=
[email protected]> wrote:

Not quite correct!聽 Ladder line is a transmission line just like coaxial
line.聽 However, they perform their function differently.

1)聽 The center fed dipole is a balanced source/load - differential
source/load.

2)聽 Ladder line is a balanced transmission line - differential
transmission line.聽 It is the correct transmission line to connect directly
to a balanced/differential source/load (dipole).聽 It does NOT participate
in radiation.聽 As a transmission line, fields close onto themselves
(between the two parallel conductors) and do not open onto free space, so
no radiation occurs.

3)聽 Coax is an unbalanced transmission line - common mode transmission
line.聽 Fields are intended to close between the inner conductor and the
inside of the outer shield/braid.聽 It is NOT the correct transmission line
to connect directly to a balanced/differential source/load (dipole).

4)聽 If coaxial cable it is connected directly to a dipole, the outer
portion of the shield/braid WILL participate in radiation and gather noise
on receive that will couple into the antenna and receiver.

5)聽 The correct manner in which to connect a coaxial transmission line
(unbalanced transmission line) to a dipole (balanced source/load) is
through a 1:1 current balun or common mode choke.聽 This will prevent the
outer layer of the coaxial braid from participating in radiation and
coupling local noise into the antenna/receiver.

6)聽 4:1, 2:1, 9:1,.......are NOT appropriate for the purpose stated in
(5).聽 These are TRANSFORMERS and NOT BALUNS.

7)聽 If you MUST use a transformer for impedance transformation, follow it
with a 1:1 current balun or common mode choke.

Dave - W脴LEV

On Wed, Aug 12, 2020 at 9:20 PM Darrell Carothers <rescuemedic1@...>
wrote:

I am slowly getting parts in to try my end fed long wire antenna. Correct
me if I am wrong. With a center fed dipole, the 300 or 450 ohm ladder

line

feeding it is part of the antenna. I would think I would use my NanoVNA

at

the end of the feed to check where it would be resonant and for SWR. If

so,

would the coax feeding the end fed long wire antenna also be considered
part of the antenna and use the NanoVNA to measure accordingly? I am told
this doesn鈥檛 need a counterpoise.

Am I correct or am I missing something?

Thanks
Darrell
N5FTW



Sent from my over-rated IPhone 7 Plus.聽 Any Mis-spellings or grammar
errors are due to my IPhone auto correct feature.

--
*Dave - W脴LEV*
*Just Let Darwin Work*

--
*Dave - W脴LEV*
*Just Let Darwin Work*

On Aug 12, 2020, at 17:30, Dave <dave@...> wrote:

锘緿补谤谤别濒濒:
I initially make a wire antenna a little longer than the formula calls for(it's easier to cut than to add wire). Put up without the autotuner. Check with the nanovna or an SWR meter(the vna gives more info). Then trim so the lowest SWR is where you will be operating. If the lowest SWR is at a freq below where you want, cut a little wire off each end. If the SWR is above the freq you want to operate at, you will need to add wire. Once the trimming is done, then you can add the auto tuner if needed.

Dave - WB6DHW

On 8/12/2020 3:07 PM, Darrell Carothers wrote:
Thank you. Excuse my beginner questions but it seems I have a lot to learn. I will be using a auto tuner. I was just trying to find out what my SWR would be on the different bands and where it would be resonant on each band so I could attempt to find out if I need to trim it to tune it a bit. I guess I need to do more research before I attempt to put it in service.

Darrell

Sent from my over-rated IPhone 7 Plus. Any Mis-spellings or grammar errors are due to my IPhone auto correct feature.

On Aug 12, 2020, at 16:59, David Eckhardt <davearea51a@...> wrote:

锘緼s far as a counterpoise goes: As a single-ended, common mode source/load,
the fields must go somewhere. They don't just abruptly stop at the feed of
the EFHW (end fed half wave). Yes, the coaxial feed WILL participate in
radiation as it forms the counterpoise to the EFHW. Some form of
decoupling must be supplied before it connects to the radio or matching
network (a.k.a., 'antenna "tuner"') or there will be "RF In the Shack". A
current choke or common mode choke installed before the coax connects to
the radio or matching network would be appropriate. Then you can connect
the VNA to that point AFTER the current balun or common mode choke.
Without that, the VNA and anything holding onto the VNA or capacitively
coupled to the VNA will become part of what you measure and part of the
antenna.

Dave - W脴LEV

On Wed, Aug 12, 2020 at 9:37 PM David Eckhardt via groups.io <davearea51a=
[email protected]> wrote:

Not quite correct! Ladder line is a transmission line just like coaxial
line. However, they perform their function differently.

1) The center fed dipole is a balanced source/load - differential
source/load.

2) Ladder line is a balanced transmission line - differential
transmission line. It is the correct transmission line to connect directly
to a balanced/differential source/load (dipole). It does NOT participate
in radiation. As a transmission line, fields close onto themselves
(between the two parallel conductors) and do not open onto free space, so
no radiation occurs.

3) Coax is an unbalanced transmission line - common mode transmission
line. Fields are intended to close between the inner conductor and the
inside of the outer shield/braid. It is NOT the correct transmission line
to connect directly to a balanced/differential source/load (dipole).

4) If coaxial cable it is connected directly to a dipole, the outer
portion of the shield/braid WILL participate in radiation and gather noise
on receive that will couple into the antenna and receiver.

5) The correct manner in which to connect a coaxial transmission line
(unbalanced transmission line) to a dipole (balanced source/load) is
through a 1:1 current balun or common mode choke. This will prevent the
outer layer of the coaxial braid from participating in radiation and
coupling local noise into the antenna/receiver.

6) 4:1, 2:1, 9:1,.......are NOT appropriate for the purpose stated in
(5). These are TRANSFORMERS and NOT BALUNS.

7) If you MUST use a transformer for impedance transformation, follow it
with a 1:1 current balun or common mode choke.

Dave - W脴LEV

On Wed, Aug 12, 2020 at 9:20 PM Darrell Carothers <rescuemedic1@...>
wrote:

I am slowly getting parts in to try my end fed long wire antenna. Correct
me if I am wrong. With a center fed dipole, the 300 or 450 ohm ladder

line

feeding it is part of the antenna. I would think I would use my NanoVNA

at

the end of the feed to check where it would be resonant and for SWR. If

so,

would the coax feeding the end fed long wire antenna also be considered
part of the antenna and use the NanoVNA to measure accordingly? I am told
this doesn鈥檛 need a counterpoise.

Am I correct or am I missing something?

Thanks
Darrell
N5FTW



Sent from my over-rated IPhone 7 Plus. Any Mis-spellings or grammar
errors are due to my IPhone auto correct feature.

--
*Dave - W脴LEV*
*Just Let Darwin Work*

--
*Dave - W脴LEV*
*Just Let Darwin Work*

聽 This has been carried to extremes by the OCF dipoles that aren't very good antennas at any frequency, in my opinion

聽 If I want to operate too far from that frequency I might
聽 use a tuner for just that although the efficiency sucks.聽

I used to use tuners.聽 No more.聽 I cut my antennas so that they are in
resonance or close.聽 If I want to operate too far from that frequency I might
use a tuner for just that although the efficiency sucks.聽 And of course the
pi network in my amplifier does the job of a tuner.聽 If the mismatch is more
than about 2:1 I balk even with a tuner.
So my old MFJ 986 sits in the closet.聽 Maybe good swap material.
Incidentally I have discovered that if you only trim one end of a dipole, the
resonant frequency changes but the match at resonance deteriorates.聽 The
upside is that the curve is a bit flatter so it covers a wider band.聽 This
has been carried to extremes by the OCF dipoles that aren't very good antennas
at any frequency, in my opinion
Bob

On Aug 12, 2020, at 22:29, Walt M. via groups.io <wa7sdy_1@...> wrote:

锘� I have but one question? What is inside the box in the picture above? It has an SO-239 input, ladder line not needed, an output for the long wire on the right, and what looks like a hook to hang the box at the shack end on the left. (Or maybe it does take a counterpoise. Then it would be an OCF dipole, sorta). The match box may already have the appropriate matching network, i.e. 9:1 (or other) balun, 1:1 choke, tapped coil, or some other circuit. I have, as a reference sort of, an MFJ vertical wire antenna for 80-6 meters with a matching circuit in a box at the feed point. Matches coax thru a tapped coil and balun (not sure what the ratio is) and has outputs for the wire and radials (has a connected set of 4 radials). I can tune this fairly easily with my MFJ-948. An analyzer (VNA & MFJ-259B) shows close to res for each band tested but I still use the tuner. I suggest looking in the box, or checking the spec sheet if there is one, to see if it already has the correct matching circuit.
Walt, WA7SDY

On Wednesday, August 12, 2020, 04:26:51 PM PDT, Jerry Gaffke via groups.io <jgaffke@...> wrote:

Bob wrote:
This has been carried to extremes by the OCF dipoles that aren't very good antennas at any frequency, in my opinion

My end-fed half-wave is the off-center-fed-dipole concept taken to the extreme.
Works great, in my opinion.
But it's difficult to get the matching network right, especially if shooting for multiband use.
I simply bought an EFHW-8010 from myantennas.com, though the facebook page
referenced in my previous post tells how to clone it.
The EFHW-8010 matching network is not tuned, so works well across pretty much all
of the HF amateur bands without adjustment and without a tuner at the transmitter.
Some weird tricks were employed to hit desired parts of the bands that are not exact harmonics.
A single band end-fed-half-wave with a tuned matching network is fairly easy to get working right,
plenty of websites describing this.

The common mode choke that Dave recommended is worth trying.
I suspect the primary reason I would use one is to eliminate local noise from getting into the receiver,
since I don't really care about the radiation pattern or a small drop in efficiency due to radiation
from the feedline.
My question to the group is, to best eliminate that local noise in the receiver, shouldn't
that choke be on the receiver end of the coax, not up at the antenna feed point?
I did try one near the receiver here, but being off grid way out in the boonies
there wasn't a noticeable difference.

Bob wrote:

If I want to operate too far from that frequency I might
use a tuner for just that although the efficiency sucks.

If you have halfway decent coax that's less than 100 yards long, are operating below 30mhz,
the antenna itself is at least as good as 4:1 SWR, and you use the tuner correctly,
efficiency should not suck.
In Maxwell's Reflections III book I referenced yesterday, I said it needed editing.
It needs editing because he keeps hammering away at this point again and again and again and again.
He did so because he kept hearing from the ham community that the antenna itself
had to be in good tune to get a decent signal out.
The power lost in the coax due to reflections between antenna feed point and antenna tuner
can be calculated, and he shows how. And at HF, it usually isn't much of an issue.
Many of the chapters are simply old QST articles from the 1970's, where he felt the need to
recapitulate as readers might not have read the previous articles. But also, the organization
of all the writing is more than a little scattered. On the other hand, it's pretty much all correct.
In my opinion.

Jerry, KE7ER

On Wed, Aug 12, 2020 at 03:37 PM, Bob Albert wrote:

I used to use tuners. No more. I cut my antennas so that they are in
resonance or close. If I want to operate too far from that frequency I might
use a tuner for just that although the efficiency sucks. And of course the
pi network in my amplifier does the job of a tuner. If the mismatch is more
than about 2:1 I balk even with a tuner.
So my old MFJ 986 sits in the closet. Maybe good swap material.
Incidentally I have discovered that if you only trim one end of a dipole, the
resonant frequency changes but the match at resonance deteriorates. The
upside is that the curve is a bit flatter so it covers a wider band. This
has been carried to extremes by the OCF dipoles that aren't very good antennas
at any frequency, in my opinion
Bob