Elecraft

Matching resonant antennas

Classic

List

Threaded

28 messages Options

ANDY DURBIN

Matching resonant antennas

"A correspondent asked me why I needed to tune a resonant antenna."

Perhaps the question should have been "why may you need to match the impedance of a resonant antenna". The answer may be that not all resonant antennas are 50 ohm. Resonance only means that inductive and capacitive reactance are equal magnitude. Resonance says nothing about the value of R.

Andy, k3wyc
______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[hidden email]

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to [hidden email]

Dr. William J. Schmidt, II

Re: Matching resonant antennas

The obvious issue is not what the radio sees... It's what can happen on the
other side of the transform. Voltages and currents that no one seems to
care about as long as their radio sees 50 ohms.

Dr. William J. Schmidt - K9HZ J68HZ 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ PJ2/K9HZ

-----Original Message-----
From: [hidden email]
[mailto:[hidden email]] On Behalf Of Andy Durbin
Sent: Wednesday, July 15, 2020 11:33 AM
To: [hidden email]
Subject: [Elecraft] Matching resonant antennas

"A correspondent asked me why I needed to tune a resonant antenna."

Perhaps the question should have been "why may you need to match the
impedance of a resonant antenna". The answer may be that not all resonant
antennas are 50 ohm. Resonance only means that inductive and capacitive
reactance are equal magnitude. Resonance says nothing about the value of R.

Andy, k3wyc
______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[hidden email]

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html Message
delivered to [hidden email]

--
This email has been checked for viruses by AVG.
https://www.avg.com

______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[hidden email]

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to [hidden email]

KEN-3

Re: Matching resonant antennas

In reply to this post by ANDY DURBIN

Yes, a resonant half wave dipole can have a feedpoint impedance of 5 ohms
to 90 ohms (SWR 10:1 to 1.8:1), but it's still resonant.

Conversely, a non-resonant antenna can have a 1:1 SWR.

Ken WA8JXM

On Wed, Jul 15, 2020 at 12:34 PM Andy Durbin <[hidden email]> wrote:

> "A correspondent asked me why I needed to tune a resonant antenna."
>
> Perhaps the question should have been "why may you need to match the
> impedance of a resonant antenna". The answer may be that not all resonant
> antennas are 50 ohm. Resonance only means that inductive and capacitive
> reactance are equal magnitude. Resonance says nothing about the value of R.
>
> Andy, k3wyc
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
> Message delivered to [hidden email]
>

David Woolley (E.L)

Re: Matching resonant antennas

You can only have a 1:1 SWR at a single impedance. If the design
impedance is purely resistive, that means you can only have 1:1 for a
resistive and therefore on-resonance load (or one that can be treated as
having no reactive behaviour at the frequencies of interest - e.g. an
ideal dummy load).

On 15/07/2020 20:30, Ken WA8JXM wrote:
> Conversely, a non-resonant antenna can have a 1:1 SWR.

______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[hidden email]

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to [hidden email]

donovanf

Re: Matching resonant antennas

In reply to this post by KEN-3

Ken's statement that " a non-resonant antenna can have a 1:1 SWR"
is patently false with the sole exception of a dummy load used as an
antenna.

73
Frank
W3LPL

----- Original Message -----

From: "Ken WA8JXM" <[hidden email]>
To: "Andy Durbin" <[hidden email]>
Cc: [hidden email]
Sent: Wednesday, July 15, 2020 7:30:58 PM
Subject: Re: [Elecraft] Matching resonant antennas

Yes, a resonant half wave dipole can have a feedpoint impedance of 5 ohms
to 90 ohms (SWR 10:1 to 1.8:1), but it's still resonant.

Conversely, a non-resonant antenna can have a 1:1 SWR.

Ken WA8JXM

On Wed, Jul 15, 2020 at 12:34 PM Andy Durbin <[hidden email]> wrote:

______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[hidden email]

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to [hidden email]

______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[hidden email]

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to [hidden email]

Elecraft mailing list

Re: Matching resonant antennas

In reply to this post by David Woolley (E.L)

On 15/07/2020 20:30, Ken WA8JXM wrote:

> Conversely, a non-resonant antenna can have a 1:1 SWR.

On Thursday, July 16, 2020, 03:33:12 AM EDT, David Woolley <[hidden email]> wrote:

> You can only have a 1:1 SWR at a single impedance. If the design
> impedance is purely resistive, that means you can only have 1:1 for a
> resistive and therefore on-resonance load (or one that can be treated as
> having no reactive behaviour at the frequencies of interest - e.g. an
> ideal dummy load).

I agree completely, but there's a "catch".

Traveling-wave antennas, such as Rhombics, or Beverages, or leaky transmission lines, are, technically, non-resonant. However, they can each present a 50 ohm feedpoint impedance that is purely resistive, and produce a 1:1 VSWR as a result. ;-)

So, whether an antenna is resonant or non-resonant isn't the issue. The issue is whether or not a load impedance contains a reactive component. If it DOES, then it can never produce a 1:1 VSWR.

73 de John, KD2BD

______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[hidden email]

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to [hidden email]

KEN-3

Re: Matching resonant antennas

So pruning a horizontal dipole will never provide a 1:1 SWR except at 0.18
wavelength above ground (the ONLY elevation where the radiation resistance
is 50 ohms)? About 97 ft for 160m, 24 ft for 40m, 6 ft for 10m? A dipole
a half wave above ground has a 70 ohm radiation resistance and therefore a
1.4:1 SWR is the absolute best?

Ken WA8JXM

On Thu, Jul 16, 2020 at 6:52 PM John Magliacane via Elecraft <
[hidden email]> wrote:

> On 15/07/2020 20:30, Ken WA8JXM wrote:
>
> > Conversely, a non-resonant antenna can have a 1:1 SWR.
>
> On Thursday, July 16, 2020, 03:33:12 AM EDT, David Woolley <
> [hidden email]> wrote:
>
> > You can only have a 1:1 SWR at a single impedance. If the design
> > impedance is purely resistive, that means you can only have 1:1 for a
> > resistive and therefore on-resonance load (or one that can be treated as
> > having no reactive behaviour at the frequencies of interest - e.g. an
> > ideal dummy load).
>
> I agree completely, but there's a "catch".
>
> Traveling-wave antennas, such as Rhombics, or Beverages, or leaky
> transmission lines, are, technically, non-resonant. However, they can each
> present a 50 ohm feedpoint impedance that is purely resistive, and produce
> a 1:1 VSWR as a result. ;-)
>
> So, whether an antenna is resonant or non-resonant isn't the issue. The
> issue is whether or not a load impedance contains a reactive component. If
> it DOES, then it can never produce a 1:1 VSWR.
>
>
> 73 de John, KD2BD
>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
> Message delivered to [hidden email]
>

Jim Brown-10

Re: Matching resonant antennas

On 7/16/2020 9:57 PM, Ken WA8JXM wrote:
> So pruning a horizontal dipole will never provide a 1:1 SWR except at 0.18
> wavelength above ground (the ONLY elevation where the radiation resistance
> is 50 ohms)? About 97 ft for 160m, 24 ft for 40m, 6 ft for 10m? A dipole
> a half wave above ground has a 70 ohm radiation resistance and therefore a
> 1.4:1 SWR is the absolute best?

No, it's FAR more complex than that. Horizontal antennas see the
reflection from the earth as a parasitic element, which adds a complex
impedance to the equivalent circuit. The reflection, and thus the
parasitic impedance, will depend on height above ground, the skin depth
of the earth, and the electrical qualities of the soil.

The ON4UN book, "Low Band DXing," includes a set of very interesting
plots of antenna impedance as a function of height and soil quality. In
general, the feedpoint Z of low dipoles oscillates as height varies,
with the average near 50 ohms, while high dipoles oscillate around 70-80
ohms. It's easy to see this in the very simple NEC model of a center-fed
dipole (the model is a wire with a generator in the center of it) by
varying the height and the soil parameters.

My dipoles for 40 and 80M are up about 125 ft in tall trees, and I have
lousy soil. The model predicts Z at resonance in the range of 85 ohms,
and I've measured 88 ohms. I feed them with RG11. Some years ago, I was
planning antennas for a CQP county expedition in a spot that has scrub
trees (max rigging height ~40 ft) and lousy soil, but is on a small
knoll, so the takeoff angle is great. NEC predicted 75 ohms for one of
them and 50 ohms for the other, so we carried RG8 for one and RG11 for
the other. When we measured them, they turned out as the NEC model
predicted.

There are computational tools and instrumentation that one can learn a
lot from if we use them to study stuff like this. NEC is one of them.

73, Jim K9YC
______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[hidden email]

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to [hidden email]

Wes Stewart-2

Re: Matching resonant antennas

In reply to this post by donovanf

If you want to pick nits then even a "perfect" dummy load doesn't match a
practical transmission line which has loss, hence has a reactive characteristic
impedance. :-)

Wes N7WS

On 7/16/2020 3:32 PM, [hidden email] wrote:
> Ken's statement that " a non-resonant antenna can have a 1:1 SWR"
> is patently false with the sole exception of a dummy load used as an
> antenna.
>
>
> 73
> Frank
> W3LPL
>

______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[hidden email]

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to [hidden email]

Edward R Cole

Re: Matching resonant antennas

In reply to this post by ANDY DURBIN

Interesting discussion:

But most of us probably tune our antennas for best SWR at the desired
frequency.

I have a dual-band 80-40m inverted-V with apex at 40-foot and 80m
wire tail at 20-foot. The separate 40m wire is spaced 6-inches from
the 80m wire with wooden dowels. I found by trial-n-error that one
must tune the lowest frequency wires, first. I did that using an
antenna analyzer. Then the 40m wires. Turns out (probably due to
coupling) that the 40m antenna is narrow bw (50-KHz at best) whereas
I get good SWR from 3650-4000 KHz.

The purist will say that's not resonant but the transmitter is
happy. I can run bypass on 3800-4000 KHz with my KXPA100/KXAT100
but must tune using the atu on 40m.
For working around Alaska (out to 800-miles) this "cloud burner"
works well with 100w. I only use SSB on these bands. 3920 is the
defacto calling/emcomm channel in AK.

When we have an earthquake, 3920 lights up (as well as 14,292) for
reporting from our remote areas. I live two miles from salt-water so
tsunami watch is common after a "big one".

73, Ed - KL7UW
http://www.kl7uw.com
Dubus-NA Business mail:
[hidden email]

______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[hidden email]

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to [hidden email]

Barry LaZar

Re: Matching resonant antennas

Resonance is over rated. The problem of believing you must have a
resonant antenna arose with the use of coax cable began. High SWRs
causes high system losses.

Prior to the widespread use of coax, open wire was used and few antenna
systems were really resonant, and nor were they reflecting a 1:1 SWR.
Back then, no one cared as tubes were used and pi-net or swinging links
were used to match to whatever was connected to the transmitter. In
fact, I once visited a site that used rhombic antennas and Sterba
curtains being fed by high power transmitters. The feed line were copper
pipes about 1/4" in diameter and spaced about 4". The SWR, I was told,
was 14:1. I asked if that was a problem of transferring energy to the
system. The answer was no as the final output stage could match it and
the system losses were low due to the type of feed line used. This was a
lesson I learned 60 years ago and haven't forgotten it. The site was the
RCA site the once stood on Montauck Point on Long Island, New York.

One point that keeps getting forgotten is the conservation of energy
concept. What that means is energy can only be changed and not lost.
Typically that means transmitter energy would be changed to heat, but
not lost. What is not changed to heat on the coax will make it to the
antenna where it MUST be radiated and not lost. Yhe practical
application of this is use really good coax if you can't get to a
1:1-2:1 SWR, ot there about. Alternatively, use ladder line and a
current balun. Elecraft tuners easily tune 10:1 SWR which contains
system losses nicely. I have been doing this for a very long time and
have achieved WAS, DXCC phone, DXCC CW, and DXCC digital, and, I'm 13
short on 80 of making 5BDXCC.

73,

Barry

K3NDM

On 7/17/2020 1:47 PM, Edward R Cole wrote:

> Interesting discussion:
>
> But most of us probably tune our antennas for best SWR at the desired
> frequency.
>
> I have a dual-band 80-40m inverted-V with apex at 40-foot and 80m wire
> tail at 20-foot. The separate 40m wire is spaced 6-inches from the
> 80m wire with wooden dowels. I found by trial-n-error that one must
> tune the lowest frequency wires, first. I did that using an antenna
> analyzer. Then the 40m wires. Turns out (probably due to coupling)
> that the 40m antenna is narrow bw (50-KHz at best) whereas I get good
> SWR from 3650-4000 KHz.
>
> The purist will say that's not resonant but the transmitter is happy.
> I can run bypass on 3800-4000 KHz with my KXPA100/KXAT100 but must
> tune using the atu on 40m.
> For working around Alaska (out to 800-miles) this "cloud burner" works
> well with 100w. I only use SSB on these bands. 3920 is the defacto
> calling/emcomm channel in AK.
>
> When we have an earthquake, 3920 lights up (as well as 14,292) for
> reporting from our remote areas. I live two miles from salt-water so
> tsunami watch is common after a "big one".
>
> 73, Ed - KL7UW
> http://www.kl7uw.com
> Dubus-NA Business mail:
> [hidden email]
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
> Message delivered to [hidden email]

Wes Stewart-2

Re: Matching resonant antennas

I wrote about some of this in my paper ARRL Antenna Compendium paper on ladder
line 20 years ago. https://sadxa.org/n7ws/Ladder_Line.pdf

I've seen pictures of those SW transmitting plants and always assumed that they
must have been very efficient. Upon reflection---no pun intended---now I'm not
so sure. If losses mounted up, (which they most certainly did at 14:1 SWR) they
had the option of just turning up the wick.

Furthermore, as I said in closing: "Contrary to the conventional wisdom, ladder
line is not a panacea for every transmission line problem." In the ensuing 20
years, I've become even more convinced of this. When tuner and balun losses are
factored into this picture I don't know why anyone would want to use this
stuff. I sure don't.

I have a KAT500 and use it to tune some way-off resonant antennas (fed with 7/8"
Heliax) but I don't delude myself into thinking "I've contained system losses."

Wes N7WS
https://www.qrz.com/db/N7WS

On 7/17/2020 2:32 PM, Barry LaZar wrote:

> Resonance is over rated. The problem of believing you must have a resonant
> antenna arose with the use of coax cable began. High SWRs causes high system
> losses.
>
> Prior to the widespread use of coax, open wire was used and few antenna
> systems were really resonant, and nor were they reflecting a 1:1 SWR. Back
> then, no one cared as tubes were used and pi-net or swinging links were used
> to match to whatever was connected to the transmitter. In fact, I once visited
> a site that used rhombic antennas and Sterba curtains being fed by high power
> transmitters. The feed line were copper pipes about 1/4" in diameter and
> spaced about 4". The SWR, I was told, was 14:1. I asked if that was a problem
> of transferring energy to the system. The answer was no as the final output
> stage could match it and the system losses were low due to the type of feed
> line used. This was a lesson I learned 60 years ago and haven't forgotten it.
> The site was the RCA site the once stood on Montauck Point on Long Island, New
> York.
>
> One point that keeps getting forgotten is the conservation of energy concept.
> What that means is energy can only be changed and not lost. Typically that
> means transmitter energy would be changed to heat, but not lost. What is not
> changed to heat on the coax will make it to the antenna where it MUST be
> radiated and not lost. Yhe practical application of this is use really good
> coax if you can't get to a 1:1-2:1 SWR, ot there about. Alternatively, use
> ladder line and a current balun. Elecraft tuners easily tune 10:1 SWR which
> contains system losses nicely. I have been doing this for a very long time and
> have achieved WAS, DXCC phone, DXCC CW, and DXCC digital, and, I'm 13 short on
> 80 of making 5BDXCC.
>
> 73,
>
> Barry
>
> K3NDM

Barry LaZar

Re: Matching resonant antennas

Wes,

     You're correct that open wire/ladder line transmission lines are
not a panacea. But, in the average ham stations, open wire does overcome
high losses with high SWR, or not so high SWR. What is needed is a look
at the ARRL Antenna book for transmission line loss/100 ft. as a
function of SWR. You see that on 10 meters running 10:1 SWR the total
loss is around 1 db. And, as you go to the lower bands, losses become
less. Typical 400 Ohm ladder line has a loss of 0.2 db at 10 MHz and 0.6
db at 100 MHz. Using these data and a little interpolation, I would use
0.4 db on 10 meters and a 10:1 SWR for this to be 0.8 db of additional
loss for a total of about 1.2 db. Yes, I do use a balun and recommend
them so add another 0.5 db. Add another 0.5 db for a good tuner and we
end up with a total of 2.2 db. on 10 meters and less on 20 and it
decomposes to an academic exercise on 40 and down.

     Coax on 10 starts out with a higher loss/100 feet. I will use what
I use here in K3NDM, Times LMR400. That represents 0.4 at 10 MHz. and
1.4 db at 100 MHz. That will yield about 1.2 db/100 ft on 10 meters. Add
0.25 db for a 2:1 SWR and 0.5 for tuner loss and you end up with about
1.95 at a 2:1 SWR.

     Here coax wins IFF the SWR remains less than 2:1 which won't happen
over the entire commonly used portion of the band. Using ladder line
vice coax will contain losses over the entire band. This keeps things
simple and the cost should be a lot less.

     As to the RCA station with a 14:1 SWR, they used no balun nor tuner
as we commonly know them today. The coupling to the final tube(s) were
balanced and was capable of making the transformation from what the tube
wanted and the reflected impedance at the transmitter end of the
transmission line. Ergo, they had a very low loss if using 10 meters
which they didn't. They typically used frequencies below 18 MHz and a
slug of power.

Vy 73,

Barry

K3NDM

On 7/17/2020 6:57 PM, Wes wrote:

> I wrote about some of this in my paper ARRL Antenna Compendium paper
> on ladder line 20 years ago. https://sadxa.org/n7ws/Ladder_Line.pdf
>
> I've seen pictures of those SW transmitting plants and always assumed
> that they must have been very efficient. Upon reflection---no pun
> intended---now I'm not so sure. If losses mounted up, (which they
> most certainly did at 14:1 SWR) they had the option of just turning up
> the wick.
>
> Furthermore, as I said in closing: "Contrary to the conventional
> wisdom, ladder line is not a panacea for every transmission line
> problem." In the ensuing 20 years, I've become even more convinced of
> this. When tuner and balun losses are factored into this picture I
> don't know why anyone would want to use this stuff. I sure don't.
>
> I have a KAT500 and use it to tune some way-off resonant antennas (fed
> with 7/8" Heliax) but I don't delude myself into thinking "I've
> contained system losses."
>
> Wes N7WS
> https://www.qrz.com/db/N7WS
>
>
> On 7/17/2020 2:32 PM, Barry LaZar wrote:
>> Resonance is over rated. The problem of believing you must have a
>> resonant antenna arose with the use of coax cable began. High SWRs
>> causes high system losses.
>>
>> Prior to the widespread use of coax, open wire was used and few
>> antenna systems were really resonant, and nor were they reflecting a
>> 1:1 SWR. Back then, no one cared as tubes were used and pi-net or
>> swinging links were used to match to whatever was connected to the
>> transmitter. In fact, I once visited a site that used rhombic
>> antennas and Sterba curtains being fed by high power transmitters.
>> The feed line were copper pipes about 1/4" in diameter and spaced
>> about 4". The SWR, I was told, was 14:1. I asked if that was a
>> problem of transferring energy to the system. The answer was no as
>> the final output stage could match it and the system losses were low
>> due to the type of feed line used. This was a lesson I learned 60
>> years ago and haven't forgotten it. The site was the RCA site the
>> once stood on Montauck Point on Long Island, New York.
>>
>> One point that keeps getting forgotten is the conservation of energy
>> concept. What that means is energy can only be changed and not lost.
>> Typically that means transmitter energy would be changed to heat, but
>> not lost. What is not changed to heat on the coax will make it to the
>> antenna where it MUST be radiated and not lost. Yhe practical
>> application of this is use really good coax if you can't get to a
>> 1:1-2:1 SWR, ot there about. Alternatively, use ladder line and a
>> current balun. Elecraft tuners easily tune 10:1 SWR which contains
>> system losses nicely. I have been doing this for a very long time and
>> have achieved WAS, DXCC phone, DXCC CW, and DXCC digital, and, I'm 13
>> short on 80 of making 5BDXCC.
>>
>> 73,
>>
>> Barry
>>
>> K3NDM
>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
> Message delivered to [hidden email]

Lyn WØLEN

Re: Matching resonant antennas

Barry -

+1

I use nothing but 600 ohm OWL (True Ladder Line) and a short piece of coax connects to a 1:1 / 4:1 hybrid balun to allow matching the impedance perfectly with my KAT500.

The antenna is a 360' center fed EDZ (design frequency of 3.5 MHz). The KAT500 matches it on all bands 160 - 6m (on 15m, it bypasses).

The measured performance indicates excellent radiation on all bands.

73
Lyn, W0LEN

-----Original Message-----
From: [hidden email] [mailto:[hidden email]] On Behalf Of Barry LaZar
Sent: Friday, July 17, 2020 7:44 PM
To: [hidden email]
Subject: Re: [Elecraft] Matching resonant antennas

Wes,

You're correct that open wire/ladder line transmission lines are
not a panacea. But, in the average ham stations, open wire does overcome
high losses with high SWR, or not so high SWR. What is needed is a look
at the ARRL Antenna book for transmission line loss/100 ft. as a
function of SWR. You see that on 10 meters running 10:1 SWR the total
loss is around 1 db. And, as you go to the lower bands, losses become
less. Typical 400 Ohm ladder line has a loss of 0.2 db at 10 MHz and 0.6
db at 100 MHz. Using these data and a little interpolation, I would use
0.4 db on 10 meters and a 10:1 SWR for this to be 0.8 db of additional
loss for a total of about 1.2 db. Yes, I do use a balun and recommend
them so add another 0.5 db. Add another 0.5 db for a good tuner and we
end up with a total of 2.2 db. on 10 meters and less on 20 and it
decomposes to an academic exercise on 40 and down.

Coax on 10 starts out with a higher loss/100 feet. I will use what
I use here in K3NDM, Times LMR400. That represents 0.4 at 10 MHz. and
1.4 db at 100 MHz. That will yield about 1.2 db/100 ft on 10 meters. Add
0.25 db for a 2:1 SWR and 0.5 for tuner loss and you end up with about
1.95 at a 2:1 SWR.

Here coax wins IFF the SWR remains less than 2:1 which won't happen
over the entire commonly used portion of the band. Using ladder line
vice coax will contain losses over the entire band. This keeps things
simple and the cost should be a lot less.

As to the RCA station with a 14:1 SWR, they used no balun nor tuner
as we commonly know them today. The coupling to the final tube(s) were
balanced and was capable of making the transformation from what the tube
wanted and the reflected impedance at the transmitter end of the
transmission line. Ergo, they had a very low loss if using 10 meters
which they didn't. They typically used frequencies below 18 MHz and a
slug of power.

Vy 73,

Barry

K3NDM

On 7/17/2020 6:57 PM, Wes wrote:

--
This email has been checked for viruses by Avast antivirus software.
https://www.avast.com/antivirus

______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[hidden email]

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to [hidden email]

______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[hidden email]

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to [hidden email]

Barry LaZar

Re: Matching resonant antennas

Lyn,

That's a reasonable design, and if you have it high, I am not
surprised it's working out well for you. Not every ham has the liberty
to put up, grow, an antenna farm. I am in that position. I have only two
antennas up, a 20 meter vertical dipole center fed which I operate 20-10
and feed it with ladder line and an 160 meter inverted L fed at the base
with a remote tuner. I also have 5 elevated radials of varying length
connected to the remote tuner , just because. Collectively, they work
out well. It sometimes amazes me how some wire in a tree or two can be
used to reach out and touch people. :-) I have never used a beam, but I
do have a KPA500 and matching tuner which I use primarily for working
100% duty cycle digital modes. All of my contesting and DX work has been
at the 100 Watt level, except Field Day when I run QRP. So, good going
and luck.

73,

Barry

K3NDM

On 7/17/2020 9:18 PM, Lyn Norstad wrote:

> Barry -
>
> +1
>
> I use nothing but 600 ohm OWL (True Ladder Line) and a short piece of coax connects to a 1:1 / 4:1 hybrid balun to allow matching the impedance perfectly with my KAT500.
>
> The antenna is a 360' center fed EDZ (design frequency of 3.5 MHz). The KAT500 matches it on all bands 160 - 6m (on 15m, it bypasses).
>
> The measured performance indicates excellent radiation on all bands.
>
> 73
> Lyn, W0LEN
>
>
> -----Original Message-----
> From: [hidden email] [mailto:[hidden email]] On Behalf Of Barry LaZar
> Sent: Friday, July 17, 2020 7:44 PM
> To: [hidden email]
> Subject: Re: [Elecraft] Matching resonant antennas
>
> Wes,
>
> You're correct that open wire/ladder line transmission lines are
> not a panacea. But, in the average ham stations, open wire does overcome
> high losses with high SWR, or not so high SWR. What is needed is a look
> at the ARRL Antenna book for transmission line loss/100 ft. as a
> function of SWR. You see that on 10 meters running 10:1 SWR the total
> loss is around 1 db. And, as you go to the lower bands, losses become
> less. Typical 400 Ohm ladder line has a loss of 0.2 db at 10 MHz and 0.6
> db at 100 MHz. Using these data and a little interpolation, I would use
> 0.4 db on 10 meters and a 10:1 SWR for this to be 0.8 db of additional
> loss for a total of about 1.2 db. Yes, I do use a balun and recommend
> them so add another 0.5 db. Add another 0.5 db for a good tuner and we
> end up with a total of 2.2 db. on 10 meters and less on 20 and it
> decomposes to an academic exercise on 40 and down.
>
> Coax on 10 starts out with a higher loss/100 feet. I will use what
> I use here in K3NDM, Times LMR400. That represents 0.4 at 10 MHz. and
> 1.4 db at 100 MHz. That will yield about 1.2 db/100 ft on 10 meters. Add
> 0.25 db for a 2:1 SWR and 0.5 for tuner loss and you end up with about
> 1.95 at a 2:1 SWR.
>
> Here coax wins IFF the SWR remains less than 2:1 which won't happen
> over the entire commonly used portion of the band. Using ladder line
> vice coax will contain losses over the entire band. This keeps things
> simple and the cost should be a lot less.
>
> As to the RCA station with a 14:1 SWR, they used no balun nor tuner
> as we commonly know them today. The coupling to the final tube(s) were
> balanced and was capable of making the transformation from what the tube
> wanted and the reflected impedance at the transmitter end of the
> transmission line. Ergo, they had a very low loss if using 10 meters
> which they didn't. They typically used frequencies below 18 MHz and a
> slug of power.
>
> Vy 73,
>
> Barry
>
> K3NDM
>
>
> On 7/17/2020 6:57 PM, Wes wrote:
>> I wrote about some of this in my paper ARRL Antenna Compendium paper
>> on ladder line 20 years ago. https://sadxa.org/n7ws/Ladder_Line.pdf
>>
>> I've seen pictures of those SW transmitting plants and always assumed
>> that they must have been very efficient. Upon reflection---no pun
>> intended---now I'm not so sure. If losses mounted up, (which they
>> most certainly did at 14:1 SWR) they had the option of just turning up
>> the wick.
>>
>> Furthermore, as I said in closing: "Contrary to the conventional
>> wisdom, ladder line is not a panacea for every transmission line
>> problem." In the ensuing 20 years, I've become even more convinced of
>> this. When tuner and balun losses are factored into this picture I
>> don't know why anyone would want to use this stuff. I sure don't.
>>
>> I have a KAT500 and use it to tune some way-off resonant antennas (fed
>> with 7/8" Heliax) but I don't delude myself into thinking "I've
>> contained system losses."
>>
>> Wes N7WS
>> https://www.qrz.com/db/N7WS
>>
>>
>> On 7/17/2020 2:32 PM, Barry LaZar wrote:
>>> Resonance is over rated. The problem of believing you must have a
>>> resonant antenna arose with the use of coax cable began. High SWRs
>>> causes high system losses.
>>>
>>> Prior to the widespread use of coax, open wire was used and few
>>> antenna systems were really resonant, and nor were they reflecting a
>>> 1:1 SWR. Back then, no one cared as tubes were used and pi-net or
>>> swinging links were used to match to whatever was connected to the
>>> transmitter. In fact, I once visited a site that used rhombic
>>> antennas and Sterba curtains being fed by high power transmitters.
>>> The feed line were copper pipes about 1/4" in diameter and spaced
>>> about 4". The SWR, I was told, was 14:1. I asked if that was a
>>> problem of transferring energy to the system. The answer was no as
>>> the final output stage could match it and the system losses were low
>>> due to the type of feed line used. This was a lesson I learned 60
>>> years ago and haven't forgotten it. The site was the RCA site the
>>> once stood on Montauck Point on Long Island, New York.
>>>
>>> One point that keeps getting forgotten is the conservation of energy
>>> concept. What that means is energy can only be changed and not lost.
>>> Typically that means transmitter energy would be changed to heat, but
>>> not lost. What is not changed to heat on the coax will make it to the
>>> antenna where it MUST be radiated and not lost. Yhe practical
>>> application of this is use really good coax if you can't get to a
>>> 1:1-2:1 SWR, ot there about. Alternatively, use ladder line and a
>>> current balun. Elecraft tuners easily tune 10:1 SWR which contains
>>> system losses nicely. I have been doing this for a very long time and
>>> have achieved WAS, DXCC phone, DXCC CW, and DXCC digital, and, I'm 13
>>> short on 80 of making 5BDXCC.
>>>
>>> 73,
>>>
>>> Barry
>>>
>>> K3NDM
>> ______________________________________________________________
>> Elecraft mailing list
>> Home: http://mailman.qth.net/mailman/listinfo/elecraft
>> Help: http://mailman.qth.net/mmfaq.htm
>> Post: mailto:[hidden email]
>>
>> This list hosted by: http://www.qsl.net
>> Please help support this email list: http://www.qsl.net/donate.html
>> Message delivered to [hidden email]

Rich NE1EE

Re: Matching resonant antennas

In reply to this post by Lyn WØLEN

This actually surfaces a question that I am currently wondering about with my own system...what is measured performance here? I have a 40m EF wire about 20m in the air, and I wonder how effective it is at radiating. I have good SWR, and I get good signal reports, but wonder if that is the whole picture?

~R~
72/73 de Rich NE1EE
On the banks of the Piscataqua

On 2020-07-17 20:18:-0500, Lyn Norstad wrote:

>The measured performance indicates excellent radiation on all bands.
>
>73
>Lyn, W0LEN

______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[hidden email]

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to [hidden email]

Lyn WØLEN

Re: Matching resonant antennas

Rich -

While I would like to be able to say that I have taken exhaustive field
strength readings in all directions on all bands at appropriate distances,
such is not the case ... nor will it ever be. I base my performance
assessment on reception reports (PSKreporter, etc.) and actual QSOs compared
to what I would predict based on NEC pattern data along with predicted
propagation.

The bottom line is that I have WAS on 160, 80, 40, 30 and 20 meters, DXCC
(actually 145 countries) and a host of other "awards" that just popped up in
the normal course of having fun and hamming it up.
And most of that was with 100 watts or less, and all of it in the 14 months
since I put up this antenna.

For me, that IS the whole picture.

73
Lyn, W0LEN

-----Original Message-----
From: [hidden email]
[mailto:[hidden email]] On Behalf Of Rich NE1EE
Sent: Saturday, July 18, 2020 5:09 AM
To: [hidden email]
Subject: Re: [Elecraft] Matching resonant antennas

This actually surfaces a question that I am currently wondering about with
my own system...what is measured performance here? I have a 40m EF wire
about 20m in the air, and I wonder how effective it is at radiating. I have
good SWR, and I get good signal reports, but wonder if that is the whole
picture?

~R~
72/73 de Rich NE1EE
On the banks of the Piscataqua

On 2020-07-17 20:18:-0500, Lyn Norstad wrote:

>The measured performance indicates excellent radiation on all bands.
>
>73
>Lyn, W0LEN

______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[hidden email]

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to [hidden email]

______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[hidden email]

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to [hidden email]

Rich NE1EE

Re: Matching resonant antennas

Great answer. Thanks much for the reality check. And this summer I was told of the reverse beacon system, too, and I intend to see how that goes. I am just getting back into HF after many years hiatus due to jobs and moving, and started learning Morse code May 1. I intend to make my first contacts in the next week, stumbling as they may be ;-) Ya gotta get wet to go swimming! I am inclined to use the least power I need, and have been following that principle since the early days. I am making a small AFC feedback circuit for my TS-830 to be able to run its power back from the 100/220W it runs at full speed. (No, I am not loading it into a wheelbarrow and carting it into the hills ;-)

I have a KX2 on order, and have been assembling parts for hiking trips: antenna, battery, key. I spend a lot of time outdoors, and figure I might as well add ham to that and enjoy the best of both worlds. I expect to be on the air on some mountain in NH by mid Aug, if the KX2 gets here by then. I fully understand the delays, so not impatient. ;-) Well, maybe a little...

Found a YouTube on PSKreporter, so will check that out.

Kind regards,
Rich

On 2020-07-18 06:20:-0500, Lyn Norstad wrote:

>Rich -
>
>While I would like to be able to say that I have taken exhaustive field
>strength readings in all directions on all bands at appropriate distances,
>such is not the case ... nor will it ever be. I base my performance
>assessment on reception reports (PSKreporter, etc.) and actual QSOs compared
>to what I would predict based on NEC pattern data along with predicted
>propagation.
>
>The bottom line is that I have WAS on 160, 80, 40, 30 and 20 meters, DXCC
>(actually 145 countries) and a host of other "awards" that just popped up in
>the normal course of having fun and hamming it up.
>And most of that was with 100 watts or less, and all of it in the 14 months
>since I put up this antenna.
>
>For me, that IS the whole picture.
>
>73
>Lyn, W0LEN
>
>-----Original Message-----
>From: [hidden email]
>[mailto:[hidden email]] On Behalf Of Rich NE1EE
>Sent: Saturday, July 18, 2020 5:09 AM
>To: [hidden email]
>Subject: Re: [Elecraft] Matching resonant antennas
>
>This actually surfaces a question that I am currently wondering about with
>my own system...what is measured performance here? I have a 40m EF wire
>about 20m in the air, and I wonder how effective it is at radiating. I have
>good SWR, and I get good signal reports, but wonder if that is the whole
>picture?
>
>~R~
>72/73 de Rich NE1EE
>On the banks of the Piscataqua
>
>On 2020-07-17 20:18:-0500, Lyn Norstad wrote:
>
>>The measured performance indicates excellent radiation on all bands.
>>
>>73
>>Lyn, W0LEN

W2xj

Re: Matching resonant antennas

In reply to this post by Lyn WØLEN

What is changing is the radiation pattern. As the frequency increases the pattern becomes more sidelobes. Some of those sidelobes are bigger than the main lobe and they radiate ‘somewhere’.

Sent from my iPhone

> On Jul 17, 2020, at 21:19, Lyn Norstad <[hidden email]> wrote:
>
> Barry -
>
> +1
>
> I use nothing but 600 ohm OWL (True Ladder Line) and a short piece of coax connects to a 1:1 / 4:1 hybrid balun to allow matching the impedance perfectly with my KAT500.
>
> The antenna is a 360' center fed EDZ (design frequency of 3.5 MHz). The KAT500 matches it on all bands 160 - 6m (on 15m, it bypasses).
>
> The measured performance indicates excellent radiation on all bands.
>
> 73
> Lyn, W0LEN
>
>
> -----Original Message-----
> From: [hidden email] [mailto:[hidden email]] On Behalf Of Barry LaZar
> Sent: Friday, July 17, 2020 7:44 PM
> To: [hidden email]
> Subject: Re: [Elecraft] Matching resonant antennas
>
> Wes,
>
> You're correct that open wire/ladder line transmission lines are
> not a panacea. But, in the average ham stations, open wire does overcome
> high losses with high SWR, or not so high SWR. What is needed is a look
> at the ARRL Antenna book for transmission line loss/100 ft. as a
> function of SWR. You see that on 10 meters running 10:1 SWR the total
> loss is around 1 db. And, as you go to the lower bands, losses become
> less. Typical 400 Ohm ladder line has a loss of 0.2 db at 10 MHz and 0.6
> db at 100 MHz. Using these data and a little interpolation, I would use
> 0.4 db on 10 meters and a 10:1 SWR for this to be 0.8 db of additional
> loss for a total of about 1.2 db. Yes, I do use a balun and recommend
> them so add another 0.5 db. Add another 0.5 db for a good tuner and we
> end up with a total of 2.2 db. on 10 meters and less on 20 and it
> decomposes to an academic exercise on 40 and down.
>
> Coax on 10 starts out with a higher loss/100 feet. I will use what
> I use here in K3NDM, Times LMR400. That represents 0.4 at 10 MHz. and
> 1.4 db at 100 MHz. That will yield about 1.2 db/100 ft on 10 meters. Add
> 0.25 db for a 2:1 SWR and 0.5 for tuner loss and you end up with about
>

Lyn WØLEN

Re: Matching resonant antennas

Exactly.

-----Original Message-----
From: W2xj [mailto:[hidden email]]
Sent: Saturday, July 18, 2020 7:37 AM
To: [hidden email]
Cc: [hidden email]; [hidden email]
Subject: Re: [Elecraft] Matching resonant antennas

What is changing is the radiation pattern. As the frequency increases the pattern becomes more sidelobes. Some of those sidelobes are bigger than the main lobe and they radiate ‘somewhere’.

Sent from my iPhone