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Tuner ranges

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Kimbottles

Tuner ranges

Is the tuner range of the K-3 and the KAT-500 the same?
They seem to tune the same antenna differently, (of course the K-3 is tuning through a bit more coax with both the KAT-500 and KPA-500 on standby.)
They are tuning a 250’ Doublet via a short coax run (10’) to an external 4:1 current Balun, then via true 600 ohm open ladder line.
(I tried a 1:1 Balun, but it did not have as great a range on 160 as using the 4:1.)
The K-3 seems to have a bit more range than the KAT-500.
Is that to be expected?
73
Kim - K7IM
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Vic Rosenthal

Re: Tuner ranges

I believe that the K3 tuner does have more range than the one in the KAT500.

My experience with this kind of system (tuner -> balun -> open wire
line) is that the 1:1 balun works much better from the point of view of
losses and choking off RF in the shack.

What do you mean that the 4:1 balun has less range on 160 than the 1:1?
If you are saying that the SWR curve is broader, then that could just be
because of losses in the balun.

73,
Victor, 4X6GP
Rehovot, Israel
Formerly K2VCO
CWops no. 5
http://www.qsl.net/k2vco/

On 24/05/2018 6:49, Michael K Bottles wrote:

> Is the tuner range of the K-3 and the KAT-500 the same?
> They seem to tune the same antenna differently, (of course the K-3 is tuning through a bit more coax with both the KAT-500 and KPA-500 on standby.)
> They are tuning a 250’ Doublet via a short coax run (10’) to an external 4:1 current Balun, then via true 600 ohm open ladder line.
> (I tried a 1:1 Balun, but it did not have as great a range on 160 as using the 4:1.)
> The K-3 seems to have a bit more range than the KAT-500.
> Is that to be expected?
> 73
> Kim - K7IM
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ke9uw

Re: Tuner ranges

In reply to this post by Kimbottles

I believe they are the same, the difference noted is due to the different paths to the antenna. Wayne answered this question for me a couple years ago.

Chuck Hawley
[hidden email]

Amateur Radio, KE9UW
aka Jack, BMW Motorcycles
________________________________________
From: [hidden email] [[hidden email]] on behalf of Michael K Bottles [[hidden email]]
Sent: Wednesday, May 23, 2018 10:49 PM
To: [hidden email]
Subject: [Elecraft] Tuner ranges

Is the tuner range of the K-3 and the KAT-500 the same?
They seem to tune the same antenna differently, (of course the K-3 is tuning through a bit more coax with both the KAT-500 and KPA-500 on standby.)
They are tuning a 250’ Doublet via a short coax run (10’) to an external 4:1 current Balun, then via true 600 ohm open ladder line.
(I tried a 1:1 Balun, but it did not have as great a range on 160 as using the 4:1.)
The K-3 seems to have a bit more range than the KAT-500.
Is that to be expected?
73
Kim - K7IM
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Chuck, KE9UW

Bob McGraw - K4TAX

Re: OT Tuner ranges

In reply to this post by Vic Rosenthal

My findings and applications agree with Victor's statement that a 1:1
current balun, specifically a Guanella balun design with added common
mode choke is the preference for using a tuner to feed a balanced or
open wire line.    For the life of me, I have never been able to
understand the general belief that a 4:1 balun should be used with open
wire feed line.   Maybe it is the "400 ohms" or "450 ohms" that is
attracted to the number "4" in the balun ratio that is the attraction.
I view it the case of the "tuner lemmings" where one started it
{incorrectly as it may be} and the rest followed.

By now most of us are well aware of the need for a 4:1 Guanella balun to
be wound onto two separate cores, not just a single core.
Unfortunately, most balun manufacturers are clueless and continue to
promote these single core baluns for OCFD antennas.   A few (e.g., Balun
Designs and Palomar Engineers) have either dual-core’s or even hybrid
baluns.

The secondary reason that the single core 4:1 Guanella is not
appropriate.    If you wrap both winding's onto a single core, each
winding has half as many turns as when you wrap them onto separate
cores. Since inductance (and CMI) increases with the square of the
number of turns, it is obvious that a single core balun could never work
anywhere nearly as well as a dual-core balun.

But the primary reason is, in HF antenna applications, a 4:1 Guanella
Balun wound onto a single core has no CMI at all; ZERO. In fact it can
even generate CMC. (Source: G3TXQ). Therefore, by definition, it is
not even a balun at all. – Yes I have read Sevick too and he shows a
single core 4:1 Guanella balun as well as a dual core, but he fails to
explain the difference. The single core will only work in applications
that are 100% ground independent, or “floating.”    No HF antenna
located here on mother earth is ground independent; thus the single-core
4:1 Guanella is not suited for HF antenna applications.

As to tuner ranges, add a length of coax or insert a piece of equipment
in the path and the Z +j is now different. Hence the appearance match
range will be different.

73

Bob, K4TAX

On 5/24/2018 3:05 AM, Victor Rosenthal 4X6GP wrote:

> I believe that the K3 tuner does have more range than the one in the
> KAT500.
>
> My experience with this kind of system (tuner -> balun -> open wire
> line) is that the 1:1 balun works much better from the point of view
> of losses and choking off RF in the shack.
>
> What do you mean that the 4:1 balun has less range on 160 than the
> 1:1? If you are saying that the SWR curve is broader, then that could
> just be because of losses in the balun.
>
> 73,
> Victor, 4X6GP
> Rehovot, Israel
> Formerly K2VCO
> CWops no. 5
> http://www.qsl.net/k2vco/

Don Wilhelm

Re: OT Tuner ranges

In general, I agree with Bob. For most situations, a 1:1 balun will
produce a good match - but it all depends.

The impedance you are matching is NOT the characteristic impedance of
the parallel feedline, but the impedance seen at the end of the parallel
feedline. That can vary from very low to very high depending on the
length of the radiator, the length of the feedline, and the frequency.

The feedline transforms the impedance of the radiator depending on the
feedline length and frequency. Study a bit of transmission line
principles to discover why that is true.

If you want to convince yourself, just connect an antenna analyzer to
the station end of the parallel feedline. If you find an extremely low
or extremely high impedance on any band you wish to operate, try adding
or subtracting 1/8 wavelength of feedline for that problem band and
measure again.

73,
Don W3FPR

On 5/24/2018 10:13 AM, Bob McGraw K4TAX wrote:

> My findings and applications agree with Victor's statement that a 1:1
> current balun, specifically a Guanella balun design with added common
> mode choke is the preference for using a tuner to feed a balanced or
> open wire line.    For the life of me, I have never been able to
> understand the general belief that a 4:1 balun should be used with open
> wire feed line.   Maybe it is the "400 ohms" or "450 ohms" that is
> attracted to the number "4" in the balun ratio that is the attraction. I
> view it the case of the "tuner lemmings" where one started it
> {incorrectly as it may be} and the rest followed.
>
> By now most of us are well aware of the need for a 4:1 Guanella balun to
> be wound onto two separate cores, not just a single core. Unfortunately,
> most balun manufacturers are clueless and continue to promote these
> single core baluns for OCFD antennas.   A few (e.g., Balun Designs and
> Palomar Engineers) have either dual-core’s or even hybrid baluns.
>
> The secondary reason that the single core 4:1 Guanella is not
> appropriate.    If you wrap both winding's onto a single core, each
> winding has half as many turns as when you wrap them onto separate
> cores. Since inductance (and CMI) increases with the square of the
> number of turns, it is obvious that a single core balun could never work
> anywhere nearly as well as a dual-core balun.
>
> But the primary reason is, in HF antenna applications, a 4:1 Guanella
> Balun wound onto a single core has no CMI at all; ZERO. In fact it can
> even generate CMC. (Source: G3TXQ). Therefore, by definition, it is
> not even a balun at all. – Yes I have read Sevick too and he shows a
> single core 4:1 Guanella balun as well as a dual core, but he fails to
> explain the difference. The single core will only work in applications
> that are 100% ground independent, or “floating.”    No HF antenna
> located here on mother earth is ground independent; thus the single-core
> 4:1 Guanella is not suited for HF antenna applications.
>
> As to tuner ranges, add a length of coax or insert a piece of equipment
> in the path and the Z +j is now different. Hence the appearance match
> range will be different.
>

Ignacy

Re: OT Tuner ranges

There are reports online that 1:1 has lower losses. My experience is that
with lower-range tuners 1:1 does not cover some frequencies but 4:1 does.

Ignacy, NO9E.

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Bob McGraw - K4TAX

Re: OT Tuner ranges

Just depends on the Z required to match.

Fact for T and L networks (a.k.a tuners) as the Z value decreases the loss increases. Acting as a 4 to 1 transformer it divides the Z by 4.

Bob, K4TAX

Sent from my iPhone

> On May 24, 2018, at 12:06 PM, Ignacy <[hidden email]> wrote:
>
> There are reports online that 1:1 has lower losses. My experience is that
> with lower-range tuners 1:1 does not cover some frequencies but 4:1 does.
>
> Ignacy, NO9E.
>
>
>
> --
> Sent from: http://elecraft.365791.n2.nabble.com/
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Bob McGraw - K4TAX

Re: OT Tuner ranges

In reply to this post by Ignacy

I've had several to ask in general, "so what or when is the correct
application for a 4:1 balun?" The folded dipole is an excellent
application and case for a 4:1 balun. The uniform folded dipole feed
impedance at resonance is ~300 ohms. When erected less than 1/2
wavelength above earth the impedance drops to near 200 ohms, depending
on height. Thus the 4:1 transformer action in the balun bring the load
to near 50 ohms.    Even it the feed Z of the folded dipole is 300 ohms,
and height above ground supports this, the SWR seen at the radio is only
1.6:1.

These thing we call baluns should have two functions to perform: (a)
unbalanced to balanced conversion, and (b) some degree of Common Mode
Rejection.    Both are equally important, although most commercial
designs fail to address item (b).

Again I agree with Don's comment earlier, the concept of using a 4:1
balun to "match the feedline Z" is purely fictitious information. The
feed line, depending on length vs. frequency being some numerical factor
of a wavelength, has some transformer action. Thus the feed Z of the
antenna and the feed line in combination, will present some value of Z
expressed as R +j.   It has little to do with the actual feed line
characteristic impedance.

If one believes the 4:1 balun matches the feed line which happens to be
600 ohms, and the feed line is correctly terminated into its 600 ohm
characteristic impedance, the feed Z at the balun is 150 ohms,
presenting a 3:1 SWR.

There is an excellent presentation on impedance matching coming up at
the Huntsville Hamfest in August.

73

Bob, K4TAX

On 5/24/2018 12:06 PM, Ignacy wrote:

> There are reports online that 1:1 has lower losses. My experience is that
> with lower-range tuners 1:1 does not cover some frequencies but 4:1 does.
>
> Ignacy, NO9E.
>
>
>
> --
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