Re: [Elecraft] how to optimize end-fed?

[Ron D'Eau Claire]

Holger: Your English is fine! 

Anything your internal KX3 ATU can match it will match with good efficiency.

Allow me a couple of observations that might help.

Your assumption about low L is correct since, in any well made matching
network, the greatest losses are when high circulating RF currents flow in
inductors and result in resistance losses in the wire. In many modern
miniature inductors using toroids, those currents can actually cause strong
enough magnetic fields to "saturate" the torodial core, causing it to heat
and consume more power. In the extreme, the core may crack. And heating the
toroid may cause it to reach its Curie temperature where its magnetic
properties change dramatically, which changes the inductance of the toroid.
In operation, that may appear a a sudden large change in the SWR after
transmitting for long enough to heat the core. 

"L-networks" such as Elecraft uses are very high efficiency matching
networks. 
Other popular networks you will find used by Hams, such as the "T" network,
may have wider matching capabilities but can produce very high losses as
well.

All passive elements, such as a coil, have some losses. So I avoid any extra
elements that aren't necessary. 

If you are feeding your antenna wire directly - it is connected directly to
the KX3 I'd not use an external coil unless the KX3 cannot find a decent
match (by decent I mean 2:1 or lower). 

If you have a transmission line between the KX3 and the antenna you need to
consider the losses in the transmission line, especially if it is a
low-impedance line such as 50-ohm coaxial. If the transmission line is not
terminated at the antenna in its characteristic impedance (e.g. 50 ohms for
common coax) there will be standing waves on the transmission line. Those
standing waves will produce areas of high currents flowing in the
transmission line and result in losses due to resistance in the wires. In
that case you can reduce the total losses by matching the transmission line
to the antenna impedance at the antenna. The KX3 may be able to match the
antenna, including the transmission line, to the KX3 but that won't reduce
losses in a mis-matched transmission line. 

73, Ron AC7AC

-Original Message-
From: Elecraft [mailto:elecraft-boun...@mailman.qth.net] On Behalf Of Holger
Schurig
Sent: Saturday, October 1, 2016 7:39 AM
To: Fred Jensen
Cc: <elecraft@mailman.qth.net>
Subject: Re: [Elecraft] how to optimize end-fed?

2016-09-30 21:59 GMT+02:00 Fred Jensen <k6...@foothill.net>:

> This is reminiscent of one of the five volumes in Douglas Adams' 
> trilogy, "The Hitchhikers Guide to the Galaxy."


I understand that either my english is very weird. Or that I can't explain
things good.

But that you and Davidthink that they must make a 42 joke on this is
definitely weird.


The question was: I can query the KX3 ATU for what it settled. I have an end
fed antenna and so I have various variables:

- used tap (1:4, 1:9, 1:16)
- some random length wire
- band

And forget an "optimal wire", I might just have switched from 12m to 10m.
Or back. Depends on what I find, propagation ...   so assume that my wire
is just some random wire, not necessary optimal for the band. And also, in
the context of my question, this is entirely irrelavant. I was never asking
about wire lengths, this is easy to read up. Okay, back to my scenario: I
just switched the new band. I'm not going to let my portable glass fiber
down because of that and change the wire length! Instead I do what a lazy OM
does: I press the TUNE button and the internal magical antenna tuner does
it's job. It's actually so magic, that it will do it's job on all taps. On
the 1:4 tap, on the 1:9 tap. And on the 1:16 tap. Woah! But I can query the
ATU for what inductance and capacitance it used to do the match.
And so my simple question was: would a lower inductance have less losses
inside the ATU?

And please: if you don't know the answer of if you think that there is no
answer, than just stay silent.


73, Holger
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Re: [Elecraft] how to optimize end-fed?

[Lynn W. Taylor, WB6UUT]

I think what the original question is missing is the fact that we are 
talking about the whole system, not just the inductor or the ATU.


The system is the final amplifier, the ATU, the feedline, the UNUN and 
the antenna.


If minimizing the loss in the ATU increases the loss elsewhere, then we 
aren't optimizing the whole system, probably the opposite.


From the subject, it's "how to optimize end-fed?" and without any other 
constraints.


On 2 meters, I've used a lot of J antennas, and found them to be pretty 
awesome performers.  It's an end-fed half-wave, with a quarter wave 
matching section.


Build one out of wire for an HF band, and the same antenna is called a Zep.

Properly trimmed, you don't need a tuner, but they're single-band.

73 -- Lynn

On 10/1/2016 10:03 AM, Logan Zintsmaster wrote:

To add to Lynn's comments, setting the balun tap to the lowest SWR means you
are minimizing the work that the
tuner has to do and as a result probably minimizing it's losses, as well.


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Re: [Elecraft] how to optimize end-fed?

[Walter Underwood]

Capacitors should usually have less loss than inductors. This is not true for 
manual turners with polyvaricons. Those are fairly lossy capacitors.

wunder
K6WRU
Walter Underwood
CM87wj
http://observer.wunderwood.org/ (my blog)

> On Oct 1, 2016, at 10:43 AM, Kevin - K4VD  wrote:
> 
> Hi Holger:
> 
> I just finished reading an article that may answer your question:
> http://www.arrl.org/files/file/Technology/tis/info/pdf/9501046.pdf
> 
> If I'm understanding it correctly, the inductor's Q factor is the issue.
> The Cout capacitance should be set to the highest value possible with the L
> and Cin supporting that for lowest SWR.  I think this means the higher the
> inductor's Q the less losses seen in the matching network. Does this mean
> the higher the inductance (higher inductive reactance) the higher Q and the
> lower loss? That's how it is looking to me.
> 
> I don't know what kind of matching network is used  in the Elecraft ATU.
> I'm hoping someone with a better understanding can verify or correct what
> I've said.
> 
> 73,
> Kevin K4VD
> 
> 
> 
> On Sat, Oct 1, 2016 at 10:39 AM, Holger Schurig 
> wrote:
> 
>> 2016-09-30 21:59 GMT+02:00 Fred Jensen :
>> 
>>> This is reminiscent of one of the five volumes in Douglas Adams' trilogy,
>>> "The Hitchhikers Guide to the Galaxy."
>> 
>> 
>> I understand that either my english is very weird. Or that I can't explain
>> things good.
>> 
>> But that you and Davidthink that they must make a 42 joke on this is
>> definitely weird.
>> 
>> 
>> The question was: I can query the KX3 ATU for what it settled. I have an
>> end fed antenna and so I have various variables:
>> 
>> - used tap (1:4, 1:9, 1:16)
>> - some random length wire
>> - band
>> 
>> And forget an "optimal wire", I might just have switched from 12m to 10m.
>> Or back. Depends on what I find, propagation ...   so assume that my wire
>> is just some random wire, not necessary optimal for the band. And also, in
>> the context of my question, this is entirely irrelavant. I was never asking
>> about wire lengths, this is easy to read up. Okay, back to my scenario: I
>> just switched the new band. I'm not going to let my portable glass fiber
>> down because of that and change the wire length! Instead I do what a lazy
>> OM does: I press the TUNE button and the internal magical antenna tuner
>> does it's job. It's actually so magic, that it will do it's job on all
>> taps. On the 1:4 tap, on the 1:9 tap. And on the 1:16 tap. Woah! But I can
>> query the ATU for what inductance and capacitance it used to do the match.
>> And so my simple question was: would a lower inductance have less losses
>> inside the ATU?
>> 
>> And please: if you don't know the answer of if you think that there is no
>> answer, than just stay silent.
>> 
>> 
>> 73, Holger
>> __
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>> Home: http://mailman.qth.net/mailman/listinfo/elecraft
>> Help: http://mailman.qth.net/mmfaq.htm
>> Post: mailto:Elecraft@mailman.qth.net
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>> This list hosted by: http://www.qsl.net
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Re: [Elecraft] how to optimize end-fed?

[Kevin - K4VD]

Hi Holger:

I just finished reading an article that may answer your question:
http://www.arrl.org/files/file/Technology/tis/info/pdf/9501046.pdf

If I'm understanding it correctly, the inductor's Q factor is the issue.
The Cout capacitance should be set to the highest value possible with the L
and Cin supporting that for lowest SWR.  I think this means the higher the
inductor's Q the less losses seen in the matching network. Does this mean
the higher the inductance (higher inductive reactance) the higher Q and the
lower loss? That's how it is looking to me.

I don't know what kind of matching network is used  in the Elecraft ATU.
I'm hoping someone with a better understanding can verify or correct what
I've said.

73,
Kevin K4VD



On Sat, Oct 1, 2016 at 10:39 AM, Holger Schurig 
wrote:

> 2016-09-30 21:59 GMT+02:00 Fred Jensen :
>
> > This is reminiscent of one of the five volumes in Douglas Adams' trilogy,
> > "The Hitchhikers Guide to the Galaxy."
>
>
> I understand that either my english is very weird. Or that I can't explain
> things good.
>
> But that you and Davidthink that they must make a 42 joke on this is
> definitely weird.
>
>
> The question was: I can query the KX3 ATU for what it settled. I have an
> end fed antenna and so I have various variables:
>
> - used tap (1:4, 1:9, 1:16)
> - some random length wire
> - band
>
> And forget an "optimal wire", I might just have switched from 12m to 10m.
> Or back. Depends on what I find, propagation ...   so assume that my wire
> is just some random wire, not necessary optimal for the band. And also, in
> the context of my question, this is entirely irrelavant. I was never asking
> about wire lengths, this is easy to read up. Okay, back to my scenario: I
> just switched the new band. I'm not going to let my portable glass fiber
> down because of that and change the wire length! Instead I do what a lazy
> OM does: I press the TUNE button and the internal magical antenna tuner
> does it's job. It's actually so magic, that it will do it's job on all
> taps. On the 1:4 tap, on the 1:9 tap. And on the 1:16 tap. Woah! But I can
> query the ATU for what inductance and capacitance it used to do the match.
> And so my simple question was: would a lower inductance have less losses
> inside the ATU?
>
> And please: if you don't know the answer of if you think that there is no
> answer, than just stay silent.
>
>
> 73, Holger
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Re: [Elecraft] how to optimize end-fed?

[Logan Zintsmaster]

I just finished typing up the pretty much the same answer.  Should have
gotten up earlier.

To add to Lynn's comments, setting the balun tap to the lowest SWR means you
are minimizing the work that the
tuner has to do and as a result probably minimizing it's losses, as well.

So to summarize...

1.  Bypass the tuner and select the balun tap that gives you the lowest SWR.

2.  Activate the tuner and enjoy lots of QSOs.

Logan



-Original Message-
From: Elecraft [mailto:elecraft-boun...@mailman.qth.net] On Behalf Of Lynn
W. Taylor, WB6UUT
Sent: Saturday, October 01, 2016 9:27 AM
To: elecraft@mailman.qth.net
Subject: Re: [Elecraft] how to optimize end-fed?

In my opinion, what you want is the lowest SWR on the feed line between the
Balun and the tuner.

The higher the mismatch, the higher the feedline loss.

Let's say you're operating on 14.300 MHz, and your wire is roughly 9.85
meters (32' 4") long.

If I did the math right, that's pretty much exactly 1/2 wave, and the
impedance at the feedpoint (the end) is near infinity.

Your 16:1 tap might be good enough to bring that into the ATU range.  
The SWR would likely be high.

Make the wire a bit longer (to get away from the exact 1/2 wave) and the
impedance comes down.

At some point, you'll get a better match (lower SWR) on the 4:1 tap than the
16:1 tap.

For some wire lengths, the 1:1 tap will give the lowest SWR between the
tuner and the wire.

I'll be honest and say that I don't know how the inductance in the tuner is
related to SWR.

If you trim the wire so that the impedance is 800 ohms (16 times 50) and use
the 16:1 tap, the SWR between the UNUN and the Tuner should be 1:1, but
we're no longer talking about "random" wires.

I'm sure those who invoked The Hitchhiker's Guide to the Galaxy were trying
to point out that, without getting into a lot of specifics, it's hard to
answer.  That's why I picked 14.300 MHz -- to make the question far more
exact.  Humor doesn't always translate, however.

Stay on 14.300 and make the wire three times longer, and the discussion
stays the same -- instead of the wire being 1/2 wave long, it's 1 1/2 waves.

Move to 7.150 and double the length of the wire, and the discussion stays
the same, only the lengths change.

This page <http://udel.edu/~mm/ham/randomWire/> talks about "random" 
wires, and the lengths that do fall near an odd multiple of 1/2 wave.  
Staying away from these lengths makes the tuner's job easier.

I'm also ignoring (on purpose) how well the antenna radiates.  It seems to
me that if the power doesn't get into the antenna, it doesn't much matter.

I'm sure we'll now hear suggestions from those who think another type of
antenna is better, but your original question is the same with a miscut
dipole as it is with a high-impedance end-fed wire.

73 -- Lynn


On 10/1/2016 7:26 AM, Holger Schurig wrote:
> My question was really: is it desirable to always aim for the lowest 
> inductance of an ATU tuning.  AFAIK this question is totally 
> independent from the wire length. If anything, I'll optimize the wire 
> length to make this happen ... or I won't care if my thesis is all bogus.

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Re: [Elecraft] how to optimize end-fed?

[Lynn W. Taylor, WB6UUT]

In my opinion, what you want is the lowest SWR on the feed line between 
the Balun and the tuner.


The higher the mismatch, the higher the feedline loss.

Let's say you're operating on 14.300 MHz, and your wire is roughly 9.85 
meters (32' 4") long.


If I did the math right, that's pretty much exactly 1/2 wave, and the 
impedance at the feedpoint (the end) is near infinity.


Your 16:1 tap might be good enough to bring that into the ATU range.  
The SWR would likely be high.


Make the wire a bit longer (to get away from the exact 1/2 wave) and the 
impedance comes down.


At some point, you'll get a better match (lower SWR) on the 4:1 tap than 
the 16:1 tap.


For some wire lengths, the 1:1 tap will give the lowest SWR between the 
tuner and the wire.


I'll be honest and say that I don't know how the inductance in the tuner 
is related to SWR.


If you trim the wire so that the impedance is 800 ohms (16 times 50) and 
use the 16:1 tap, the SWR between the UNUN and the Tuner should be 1:1, 
but we're no longer talking about "random" wires.


I'm sure those who invoked The Hitchhiker's Guide to the Galaxy were 
trying to point out that, without getting into a lot of specifics, it's 
hard to answer.  That's why I picked 14.300 MHz -- to make the question 
far more exact.  Humor doesn't always translate, however.


Stay on 14.300 and make the wire three times longer, and the discussion 
stays the same -- instead of the wire being 1/2 wave long, it's 1 1/2 waves.


Move to 7.150 and double the length of the wire, and the discussion 
stays the same, only the lengths change.


This page  talks about "random" 
wires, and the lengths that do fall near an odd multiple of 1/2 wave.  
Staying away from these lengths makes the tuner's job easier.


I'm also ignoring (on purpose) how well the antenna radiates.  It seems 
to me that if the power doesn't get into the antenna, it doesn't much 
matter.


I'm sure we'll now hear suggestions from those who think another type of 
antenna is better, but your original question is the same with a miscut 
dipole as it is with a high-impedance end-fed wire.


73 -- Lynn


On 10/1/2016 7:26 AM, Holger Schurig wrote:

My question was really: is it desirable to always aim for the lowest
inductance of an ATU tuning.  AFAIK this question is totally independent
from the wire length. If anything, I'll optimize the wire length to make
this happen ... or I won't care if my thesis is all bogus.


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Re: [Elecraft] how to optimize end-fed?

[Heinz Baertschi]

Holger, 

Your question was indeed crystal clear, so I am sorry that you had to make
this experience.
Don't worry and have fun!

BTW, I suspect that the tuning algorithm used by Wayne for all the AT of
Elecraft does start his try with the minimum inductance (unknown from
competitive reasons, hi)?

73, Heinz HB9BCB




--
View this message in context: 
http://elecraft.365791.n2.nabble.com/how-to-optimize-end-fed-tp7622927p7623004.html
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Re: [Elecraft] how to optimize end-fed?

[Heinz Baertschi]

Holger Schurig-2 wrote
> I have an end-fed antenna with some random wire. The UNUN at one end of it
> has three sockets to plug the random wire in: 1:4, 1:9 and 1:16.
> 
> My KX3 has the built-in ATU.
> I now want to find out on which band I best use which one of the sockets.
> 
> Am I right to assume that the ATU settings with the lowest L is always the
> best?  So when I have (for the three sockets), these values,
> 
> L: 0.12 mH,  C: 203.0 pF on transmitter side
> L: 0.0 mH,  C: 246.0 pF on transmitter side
> L: 0.0 mH,  C: 256.0 pF on antenna side   (but lowest SWR 1.2-1)
> 
> ... that the middle socket is the best?

Your question was indeed crystal clear, so I am sorry that you had to make
this experience.
Don't worry and have fun!

BTW, I suspect that the tuning algorithm used by Wayne for all the AT of
Elecraft does start his try with the minimum inductance (unknown from
competitive reasons, hi)?





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Re: [Elecraft] how to optimize end-fed?

[Holger Schurig]

2016-09-30 21:59 GMT+02:00 Fred Jensen :

> This is reminiscent of one of the five volumes in Douglas Adams' trilogy,
> "The Hitchhikers Guide to the Galaxy."


I understand that either my english is very weird. Or that I can't explain
things good.

But that you and Davidthink that they must make a 42 joke on this is
definitely weird.


The question was: I can query the KX3 ATU for what it settled. I have an
end fed antenna and so I have various variables:

- used tap (1:4, 1:9, 1:16)
- some random length wire
- band

And forget an "optimal wire", I might just have switched from 12m to 10m.
Or back. Depends on what I find, propagation ...   so assume that my wire
is just some random wire, not necessary optimal for the band. And also, in
the context of my question, this is entirely irrelavant. I was never asking
about wire lengths, this is easy to read up. Okay, back to my scenario: I
just switched the new band. I'm not going to let my portable glass fiber
down because of that and change the wire length! Instead I do what a lazy
OM does: I press the TUNE button and the internal magical antenna tuner
does it's job. It's actually so magic, that it will do it's job on all
taps. On the 1:4 tap, on the 1:9 tap. And on the 1:16 tap. Woah! But I can
query the ATU for what inductance and capacitance it used to do the match.
And so my simple question was: would a lower inductance have less losses
inside the ATU?

And please: if you don't know the answer of if you think that there is no
answer, than just stay silent.


73, Holger
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Re: [Elecraft] how to optimize end-fed?

[Holger Schurig]

>
> You will have to get more specific about the wire lengths and the band(s)
> of operation for specific answers


Nope. I don't have.

My question was really: is it desirable to always aim for the lowest
inductance of an ATU tuning.  AFAIK this question is totally independent
from the wire length. If anything, I'll optimize the wire length to make
this happen ... or I won't care if my thesis is all bogus.
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Re: [Elecraft] how to optimize end-fed?

[Fred Jensen]

Yes ... and forty three is held in reverence by others who attribute 
magical properties to it. :-)


73,

Fred K6DGW
- Sparks NV DM09dn

- Northern California Contest Club
- CU in the Cal QSO Party 1-2 Oct 2016
- www.cqp.org

On 9/30/2016 1:22 PM, David Kuechenmeister wrote:

I think 42 might be a valid answer, depending on the question.
Forty-one is certainly a good answer! There are a couple pages that
try to address the question of what long wire lengths are the easiest
to tune, i.e. present a low SWR to the matching unit. The first is at
http://udel.edu/~mm/ham/randomWire/ and it's work is derived from
what was presented here,
http://www.qsl.net/on7dy/Documentation/Best%20%20Random%20Wire%20Antenna%20Lengths.htm

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Re: [Elecraft] how to optimize end-fed?

[David Kuechenmeister]

I think 42 might be a valid answer, depending on the question. Forty-one is 
certainly a good answer!
There are a couple pages that try to address the question of what long wire 
lengths are the easiest to tune, i.e. present a low SWR to the matching unit.
The first is at http://udel.edu/~mm/ham/randomWire/ and it's work is derived 
from what was presented here, 
http://www.qsl.net/on7dy/Documentation/Best%20%20Random%20Wire%20Antenna%20Lengths.htm
Hope this helps a little. With my KX3 tuner, it doesn't seem to matter much 
what I use for a long wire. The tuner does a good job matching the antenna to 
the rig.
vy 73,Dave N4KD 

On Friday, September 30, 2016 4:01 PM, Fred Jensen  
wrote:
 

 Let me see if I understand the question:  You're looking for a simple 
algorithm to tell you how to "best" deploy a wire of indeterminate 
length in a configuration yet to be specified using a transformer of 
indefinite impedance ratio on any of a number of unnamed bands.

This is reminiscent of one of the five volumes in Douglas Adams' 
trilogy, "The Hitchhikers Guide to the Galaxy."  The people build a very 
powerful computer and then asked it, "What is the meaning of the 
Universe?"  The computer begins to compute, as is the wont of computers, 
and worked on the problem for a very long time.  Finally, it announced 
that it had determined the answer.  By this time, there was no one in 
the Universe that remembered the original question.  When asked for the 
answer, the computer replied, "Forty Two."

Possibly "forty two" would work for you as a rule of thumb? :-))

73,

Fred K6DGW
- Sparks NV DM09dn

- Northern California Contest Club
- CU in the Cal QSO Party 1-2 Oct 2016
- www.cqp.org

On 9/29/2016 11:24 PM, Holger Schurig wrote:
> Fred Jensen  writes:
>
>> How long is the wire?
>> What band?
>
> Who knowns?  I'm not asking for a *specific* optimization, I'm asking
> for a general rule of thumb.
>
> I'm not talking about a permanent installation, I'm talking about going
> to some field, or hill. I don't know the band in advance, I don't know
> the propagation conditions. And I have several lengths of wire with me,
> I can adjust the wire length. And given the circumstances of the
> location, even the layout of my wire (only on fiber glass post, between
> tree and fiber glass post, etc) will change (e.g. sloper, vertical,
> etc). Even the high will be undefined and/or changeable.

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Re: [Elecraft] how to optimize end-fed?

[Fred Jensen]

Let me see if I understand the question:  You're looking for a simple 
algorithm to tell you how to "best" deploy a wire of indeterminate 
length in a configuration yet to be specified using a transformer of 
indefinite impedance ratio on any of a number of unnamed bands.


This is reminiscent of one of the five volumes in Douglas Adams' 
trilogy, "The Hitchhikers Guide to the Galaxy."  The people build a very 
powerful computer and then asked it, "What is the meaning of the 
Universe?"  The computer begins to compute, as is the wont of computers, 
and worked on the problem for a very long time.  Finally, it announced 
that it had determined the answer.  By this time, there was no one in 
the Universe that remembered the original question.  When asked for the 
answer, the computer replied, "Forty Two."


Possibly "forty two" would work for you as a rule of thumb? :-))

73,

Fred K6DGW
- Sparks NV DM09dn

- Northern California Contest Club
- CU in the Cal QSO Party 1-2 Oct 2016
- www.cqp.org

On 9/29/2016 11:24 PM, Holger Schurig wrote:

Fred Jensen  writes:


How long is the wire?
What band?


Who knowns?  I'm not asking for a *specific* optimization, I'm asking
for a general rule of thumb.

I'm not talking about a permanent installation, I'm talking about going
to some field, or hill. I don't know the band in advance, I don't know
the propagation conditions. And I have several lengths of wire with me,
I can adjust the wire length. And given the circumstances of the
location, even the layout of my wire (only on fiber glass post, between
tree and fiber glass post, etc) will change (e.g. sloper, vertical,
etc). Even the high will be undefined and/or changeable.


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Re: [Elecraft] how to optimize end-fed?

[Lynn W. Taylor, WB6UUT]

Maybe I'm missing something, but you have a selection of taps, the 
highest is 16:1.


If the wire is exactly 1/2 wave, then the impedance is going to be very 
high, and the 16:1 tap will come closest to matching a high impedance load.


If the wire is some multiple of 1/4 wave but not a an even multiple (not 
an multiple of a half wave) then the lowest tap is probably best.


I'd disable the tuner and check the SWR on each tap for each band -- if 
I wanted to verify the (very simple) math.


73 -- Lynn

On 9/29/2016 11:24 PM, Holger Schurig wrote:

The most easy thing to change (because it's often near the bottom) is
the UNUN tap I'm using.


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Re: [Elecraft] how to optimize end-fed?

[Don Wilhelm]

Holger,

There are many answers to your questions.  You will have to get more 
specific about the wire lengths and the band(s) of operation for 
specific answers.


If you want an easy antenna that will work for 40 thru 10 meters with no 
feedline, download the KXAT1 manual from Elecraft and look at page 10.  
It is just two wires and a BNC to binding post adapter, you can't get 
much simpler than that.


If you just want to experiment with antennas, feedlines and matching 
networks, do it with some education - get the ARRL Handbook and the ARRL 
Antenna Book ans spend some time studying while doing your experiments.


73,
Don W3FPR

On 9/30/2016 2:24 AM, Holger Schurig wrote:

Fred Jensen  writes:


How long is the wire?
What band?

Who knowns?  I'm not asking for a *specific* optimization, I'm asking
for a general rule of thumb.

I'm not talking about a permanent installation, I'm talking about going
to some field, or hill. I don't know the band in advance, I don't know
the propagation conditions. And I have several lengths of wire with me,
I can adjust the wire length. And given the circumstances of the
location, even the layout of my wire (only on fiber glass post, between
tree and fiber glass post, etc) will change (e.g. sloper, vertical,
etc). Even the high will be undefined and/or changeable.

That is actually to fun (for me): to change things and try out.




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Re: [Elecraft] how to optimize end-fed?

[F5vjc]

If you are working QRP, take a look at
http://www.qrpproject.de/UK/atu.htm

This describes the 'Fuchs' half wave antenna and a matching unit in kit
form. I have built this, very compact,  it works well, gives a good
indication of optimum tune adjustment and is not totally dependent on a
good radial ground system.

73, Denis F5VJC

On 30 September 2016 at 08:29, Holger Schurig 
wrote:

> > Then I should go for the highest impedance and select 1:16, should I?
>
> I meant antenna impedance, not the impedance of the internal ATU
> inductor.
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Re: [Elecraft] how to optimize end-fed?

[Holger Schurig]

> Then I should go for the highest impedance and select 1:16, should I?

I meant antenna impedance, not the impedance of the internal ATU
inductor.
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Re: [Elecraft] how to optimize end-fed?

[Holger Schurig]

Fred Jensen  writes:

> How long is the wire?
> What band?

Who knowns?  I'm not asking for a *specific* optimization, I'm asking
for a general rule of thumb.

I'm not talking about a permanent installation, I'm talking about going
to some field, or hill. I don't know the band in advance, I don't know
the propagation conditions. And I have several lengths of wire with me,
I can adjust the wire length. And given the circumstances of the
location, even the layout of my wire (only on fiber glass post, between
tree and fiber glass post, etc) will change (e.g. sloper, vertical,
etc). Even the high will be undefined and/or changeable.

That is actually to fun (for me): to change things and try out.

But then arises the question: if I change this or that ... how can I
find out what setting is "good" or maybe even "best". Assuming I have
only the things with me that I normally have with me when I'm in the
field: KX3 and laptop.

The most easy thing to change (because it's often near the bottom) is
the UNUN tap I'm using. And I can check the LC-setting in the ATU.

And now I would like to know if there is a method --- in the field ---
where I can optimize wire and tap. And if a low inductance of the ATU
could be measure for it. And if this is true in both setings (the
inducator can be at the antenna side or at the radio side).


So either this question has never been solved amongst the readers here
... or I'm completely on the wrong track and shouldn't care at all what
the ATU finds as a match.



So far Ron's answer come the farthest in answering the question, he
optimizes for a high impedance. Then I should go for the highest
impedance and select 1:16, should I?


73,
Holger DHSHS
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Re: [Elecraft] how to optimize end-fed?

[Jim Brown]

This discussion makes me wonder if the ARRL Handbook and the ARRL 
Antenna Book have somehow been banned! This is BASIC antennas, guys. 
This is not CB radio, it is ham radio, and we're supposed to be able to 
study this stuff and figure it out!  Building antennas is one the 
easiest parts of ham radio to do yourself, and once you've invested the 
time to learn the fundamentals, it's a lot of fun!


New copies of these books can be bought for less than the cost of the 
overpriced antennas mentioned here that mostly don't work very well, 
while the cost of the wire to build much better antennas can be had for 
a few dollars! Wire as small as #22 works fine for temporary wire 
antennas for QRP operation. Insulators are easy to improvise with piece 
of plastic with holes drilled in them.


While we can make a wire of random length load (take power) and radiate, 
it's far easier if we make it a quarter wave. "One size fits all" 
antennas are like "one size fits all" clothing. They work, sort of, but 
FITS (and LOOKS) a heckuva lot better.


The most expensive part of a vertical for portable or hiking operation 
is whatever you use to hold it up. I paid about $100 for a 10M long 
telescoping fiberglass pole that collapses to 1 M. Tape the wire to it, 
run out a couple of radials, and you've got a great antenna for any band 
between 40M and 10M (just trim the wires to a quarter wave on the band 
you want to work). For less than $10, you could do the same with 2-3 10 
ft lengths of 1/2-in PVC conduit.


The picture of me on my qrz.com page is from our Chicago club's annual 
QRP night in a local park My antenna was #22 wire wound on that 10M 
pole, the pole was wedged between the seat and the top of the picnic 
bench so it was at roughly 45 degrees to vertical, and I had one or two 
radials laying on the ground. In a few hours, I made a half dozen QSOs 
on 30M, including busting a pileup.  A few years ago, W6GJB and I set up 
on a peak near Sacramento with a KX3 running on internal AAs into a 
similar antenna for 15M. We worked three continents in about 10 minutes. 
There were two radials laying on top of low brush. The vertical element 
was held up by a small tripod intended for a small camera.


Nothing personal intended, but my opinion of virtually all of these 
antennas you buy comes under the heading of "a fool and his money."


73, Jim K9YC

On Thu,9/29/2016 12:50 PM, Holger Schurig wrote:

Hi all,

I have an end-fed antenna with some random wire. The UNUN at one end of it
has three sockets to plug the random wire in: 1:4, 1:9 and 1:16.

My KX3 has the built-in ATU.

I now want to find out on which band I best use which one of the sockets.
As a first step, I wrote a simple program kx3lc.py (see
https://gist.github.com/anonymous/5d53f5bdbc50782a9d5e2c8d7062be69) that
can give me an output like this:

holger@laptop:/usr/src/afu/kx3/swr$ ./kx3lc.py
L: 0.12 mH,  C: 203.0 pF on transmitter side


Am I right to assume that the ATU settings with the lowest L is always the
best?  So when I have (for the three sockets), these values,

L: 0.12 mH,  C: 203.0 pF on transmitter side
L: 0.0 mH,  C: 246.0 pF on transmitter side
L: 0.0 mH,  C: 256.0 pF on antenna side   (but lowest SWR 1.2-1)

... that the middle socket is the best?

73
Holger, DH3HS






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Re: [Elecraft] how to optimize end-fed?

[Ron D'Eau Claire]

I have such a tuner that I built years ago because my favorite antennas are
doublets (center fed wires of various lengths) or, when necessary, an end
fed wire. In the latter case I prefer a 1/2 or multiple of 1/2 wave long
wire because the very high impedance at the feed point means very low
"ground" currents and so very low "ground" losses. 

Mine has a center link that is tuned with a variable cap in series and a
split rotor variable cap across the main coil. Taps set the number of active
turns in the link and the main coil. The feeders are tapped onto the main
coil as well. 

With all those taps (accomplished by alligator clips) it looks like
something Igor would have in Dr. Frankenstein's lab, hence my name for it:
Frankentuner. 

It takes a little fiddling to find the tap positions but once noted one can
switch bands quite easily. If feeding a doublet, the taps are set
equidistant from the center. The further toward the end, the higher the
impedance being presented by the feeders. At the other extreme, the main
coil can be opened at the center to put the feeder in series with the main
coil for very low impedances. For an end-fed wire, only one tap is used
where it best matches the impedance of the radiator. The right positions are
found with two criteria: 1) low SWR on the link between the Frankentuner and
the rig and 2) lowest over all "Q" in the tuner (high Q results in
unnecessarily high circulating currents and losses and requires more
frequent adjustment while moving around a band). 

It's a design that was very popular in the days before the demand to hop
across the Ham bands in milliseconds. It does take 15 or 30 seconds to
configure it for a new band and a few more to do a "tune" for adjusting the
caps. It does not fit in a tiny enclosure with nice lighted buttons that
look "modern". All I care about is that it works.

73, Ron AC7AC

 
-Original Message-
From: Elecraft [mailto:elecraft-boun...@mailman.qth.net] On Behalf Of Don
Wilhelm
Sent: Thursday, September 29, 2016 5:41 PM
To: elecraft@mailman.qth.net
Subject: Re: [Elecraft] how to optimize end-fed?

Mel,

Your points are well taken when you are feeding an end-fed half wave or a
radiator of a multiple of a half wave.

The ideal parallel tank circuit should be fed with a coupling coil that is
isolated from the larger secondary coil - that reduces or eliminates common
mode currents in the shack.

That solution is practical for open coil configurations where the user can
tap the antenna to any point on the coil of the tuned circuit.  
However, the tapping choices are limited in a compact, portable
implementation for use in portable operation which use toroids for the
inductor.

We used to use those isolated link coupled ATUs constructed of open coil
inductors where it was practical to tap the coil at any point, but today's
world of toroid wound inductors, that is not as easy.

If one has a resonant parallel tuned circuit, it will match very high
impedance, and a series tuned circuit will match very low impedance.  
The link coupling will provide isolation from common mode currents.

Those type of ATU's work very well with a wide range of antennas with
varying feedpoint impedance.

However, the physical implementation of the ability to tap the antenna to
any turn of the high impedance tuned resonant inductor requires a physically
large coil.  While it will work *very* well, it is not consistent with small
ATUs used for portable operation.

If you have a fixed length radiator and work only a single band, you can
devise a link coupled tuner that will do a great job, but if you are
multiband, and do not want to fiddle with coil taps, the auto-transformer is
a good compromise.

Yes, I still have my link coupled ATUs with plug-in coils for each band and
also have a Johnson Matchbox which is also link coupled. They do the job
well, but the convenience of toroid wound ATUs is an advantage in simplicity
and convenience.


73,
Don W3FPR

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Re: [Elecraft] how to optimize end-fed?

[Don Wilhelm]

Mel,

Your points are well taken when you are feeding an end-fed half wave or 
a radiator of a multiple of a half wave.


The ideal parallel tank circuit should be fed with a coupling coil that 
is isolated from the larger secondary coil - that reduces or eliminates 
common mode currents in the shack.


That solution is practical for open coil configurations where the user 
can tap the antenna to any point on the coil of the tuned circuit.  
However, the tapping choices are limited in a compact, portable 
implementation for use in portable operation which use toroids for the 
inductor.


We used to use those isolated link coupled ATUs constructed of open coil 
inductors where it was practical to tap the coil at any point, but 
today's world of toroid wound inductors, that is not as easy.


If one has a resonant parallel tuned circuit, it will match very high 
impedance, and a series tuned circuit will match very low impedance.  
The link coupling will provide isolation from common mode currents.


Those type of ATU's work very well with a wide range of antennas with 
varying feedpoint impedance.


However, the physical implementation of the ability to tap the antenna 
to any turn of the high impedance tuned resonant inductor requires a 
physically large coil.  While it will work *very* well, it is not 
consistent with small ATUs used for portable operation.


If you have a fixed length radiator and work only a single band, you can 
devise a link coupled tuner that will do a great job, but if you are 
multiband, and do not want to fiddle with coil taps, the 
auto-transformer is a good compromise.


Yes, I still have my link coupled ATUs with plug-in coils for each band 
and also have a Johnson Matchbox which is also link coupled. They do the 
job well, but the convenience of toroid wound ATUs is an advantage in 
simplicity and convenience.



73,
Don W3FPR

On 9/29/2016 8:04 PM, Mel Farrer via Elecraft wrote:

Fred said it right,

Let me go to another side of the question.  No auto-transformer can match all 
of the antenna reflected impedances,  but using a parallel tank circuit to 
ground CAN.  The beauty of this arrangement is that you can tap the coil on the 
input of the coil and tap the output for a VERY wide range of impedance.  R and 
j .  What seems to have been lost in the transition from ancient and now is 
that we did not have ATU's.  All of the PRE now used tuned circuit match boxes. 
 Now you have to think about it for a few minutes.
Let me explain, the tuned parallel tank circuit can do a wide range of matching 
BECAUSE, If you tun the tank to one side of resonance your get a negative 
reactance,  if you tune it to the other side you get positive reactance.   
HUMMM.
If the tank circuit is a true resonant one, the impedance across the coil from 
top to bottom is a range of the impedance available from HIZ to ZERO.  This is 
the beauty of the parallel tuned circuit over a auto transformer.  Oh well at 
least I remember it.
Mel, K6KBE



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Re: [Elecraft] how to optimize end-fed?

[Mel Farrer via Elecraft]

Fred said it right,  

Let me go to another side of the question.  No auto-transformer can match all 
of the antenna reflected impedances,  but using a parallel tank circuit to 
ground CAN.  The beauty of this arrangement is that you can tap the coil on the 
input of the coil and tap the output for a VERY wide range of impedance.  R and 
j .  What seems to have been lost in the transition from ancient and now is 
that we did not have ATU's.  All of the PRE now used tuned circuit match boxes. 
 Now you have to think about it for a few minutes.
Let me explain, the tuned parallel tank circuit can do a wide range of matching 
BECAUSE, If you tun the tank to one side of resonance your get a negative 
reactance,  if you tune it to the other side you get positive reactance.   
HUMMM.
If the tank circuit is a true resonant one, the impedance across the coil from 
top to bottom is a range of the impedance available from HIZ to ZERO.  This is 
the beauty of the parallel tuned circuit over a auto transformer.  Oh well at 
least I remember it.
Mel, K6KBE




  From: Fred Jensen <k6...@foothill.net>
 To: elecraft@mailman.qth.net 
 Sent: Thursday, September 29, 2016 1:57 PM
 Subject: Re: [Elecraft] how to optimize end-fed?
   
> Am I right to assume that the ATU settings with the lowest L is
 > always the best?

I don't know exactly what you mean by "best," but you said "always" so 
I'd say no.  If the length of your wire is in the vicinity of n * 90 
degrees where n is any odd integer, it will have a low-ish impedance at 
the end and 1:1 would be appropriate [if your UNUN had it].  If the 
length is around 180 degrees [or any integer multiple thereof] it will 
exhibit a fairly high impedance.

How long is the wire?
What band?

If the 1:4, 1:9, and 1:16 that you quote are turns ratios, the impedance 
transformation equals the square of them.  12,800 ohms and a 16:1 turns 
ratio yields 50 ohms.  12 Kohms likely exceeds the impedance at the end 
of a half-wave by quite a bit.

The Elecraft ATU losses are very low unless you're trying to match some 
outrageous impedance at the end of or beyond it's useful range.

73,

Fred K6DGW
Sparks NV USA
Washoe County DM09dn

On 9/29/2016 12:50 PM, Holger Schurig wrote:
> Hi all,
>
> I have an end-fed antenna with some random wire. The UNUN at one end of it
> has three sockets to plug the random wire in: 1:4, 1:9 and 1:16.
>
> My KX3 has the built-in ATU.
>
> I now want to find out on which band I best use which one of the sockets.
> As a first step, I wrote a simple program kx3lc.py (see
> https://gist.github.com/anonymous/5d53f5bdbc50782a9d5e2c8d7062be69) that
> can give me an output like this:
>
> holger@laptop:/usr/src/afu/kx3/swr$ ./kx3lc.py
> L: 0.12 mH,  C: 203.0 pF on transmitter side
>
>
> Am I right to assume that the ATU settings with the lowest L is always the
> best?  So when I have (for the three sockets), these values,
>
> L: 0.12 mH,  C: 203.0 pF on transmitter side
> L: 0.0 mH,  C: 246.0 pF on transmitter side
> L: 0.0 mH,  C: 256.0 pF on antenna side  (but lowest SWR 1.2-1)
>
> ... that the middle socket is the best?
>
> 73
> Holger, DH3HS

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Re: [Elecraft] how to optimize end-fed?

[Fred Jensen]

> Am I right to assume that the ATU settings with the lowest L is
> always the best?

I don't know exactly what you mean by "best," but you said "always" so 
I'd say no.  If the length of your wire is in the vicinity of n * 90 
degrees where n is any odd integer, it will have a low-ish impedance at 
the end and 1:1 would be appropriate [if your UNUN had it].  If the 
length is around 180 degrees [or any integer multiple thereof] it will 
exhibit a fairly high impedance.


How long is the wire?
What band?

If the 1:4, 1:9, and 1:16 that you quote are turns ratios, the impedance 
transformation equals the square of them.  12,800 ohms and a 16:1 turns 
ratio yields 50 ohms.  12 Kohms likely exceeds the impedance at the end 
of a half-wave by quite a bit.


The Elecraft ATU losses are very low unless you're trying to match some 
outrageous impedance at the end of or beyond it's useful range.


73,

Fred K6DGW
Sparks NV USA
Washoe County DM09dn

On 9/29/2016 12:50 PM, Holger Schurig wrote:

Hi all,

I have an end-fed antenna with some random wire. The UNUN at one end of it
has three sockets to plug the random wire in: 1:4, 1:9 and 1:16.

My KX3 has the built-in ATU.

I now want to find out on which band I best use which one of the sockets.
As a first step, I wrote a simple program kx3lc.py (see
https://gist.github.com/anonymous/5d53f5bdbc50782a9d5e2c8d7062be69) that
can give me an output like this:

holger@laptop:/usr/src/afu/kx3/swr$ ./kx3lc.py
L: 0.12 mH,  C: 203.0 pF on transmitter side


Am I right to assume that the ATU settings with the lowest L is always the
best?  So when I have (for the three sockets), these values,

L: 0.12 mH,  C: 203.0 pF on transmitter side
L: 0.0 mH,  C: 246.0 pF on transmitter side
L: 0.0 mH,  C: 256.0 pF on antenna side   (but lowest SWR 1.2-1)

... that the middle socket is the best?

73
Holger, DH3HS


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[Elecraft] how to optimize end-fed?

[Holger Schurig]

Hi all,

I have an end-fed antenna with some random wire. The UNUN at one end of it
has three sockets to plug the random wire in: 1:4, 1:9 and 1:16.

My KX3 has the built-in ATU.

I now want to find out on which band I best use which one of the sockets.
As a first step, I wrote a simple program kx3lc.py (see
https://gist.github.com/anonymous/5d53f5bdbc50782a9d5e2c8d7062be69) that
can give me an output like this:

holger@laptop:/usr/src/afu/kx3/swr$ ./kx3lc.py
L: 0.12 mH,  C: 203.0 pF on transmitter side


Am I right to assume that the ATU settings with the lowest L is always the
best?  So when I have (for the three sockets), these values,

L: 0.12 mH,  C: 203.0 pF on transmitter side
L: 0.0 mH,  C: 246.0 pF on transmitter side
L: 0.0 mH,  C: 256.0 pF on antenna side   (but lowest SWR 1.2-1)

... that the middle socket is the best?

73
Holger, DH3HS




PS: those values are all bogus, I measured when when my end-fed was in a
big curl inside my shack ...
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