Discussion:
high-power tuner
(too old to reply)
Ian Kahn
2012-02-24 14:05:06 UTC
Permalink
All,

I find myself finally admitting that I need an antenna tuner that supports
high power. I run a K3/P3 combo with an Ameritron AL-811H amp. Since we
are still waiting on word about pricing and release date for the KAT500, I
find myself looking at other alternatives for a 1 - 1.5 KW auto tuner.
What are others using? Several people I know have had issues with the LDG
AT-1000PRO, so I probably want to stay away from that one.

Thanks in advance for the advice.

73,

-- Ian
Ian Kahn, KM4IK
Roswell, GA EM74ua
km4ik.ian at gmail.com
K3 #281, P3 #688
Bill Hammond
2012-02-24 16:23:48 UTC
Permalink
Hi Ian,
Many of us are in that boat. I don't believe the KTA500 is vaperware. I'm just cooling my heals for the reason you cited, unreliable products from the competition. I want good products and great support from people that care about their customers. That is worth the wait, even if it is until the end of the year. Heck the K3 tuner will load a hairpin, I would expect the KTA500 will as well. If I just couldn't wait any longer ,I think I would find a manual tuner to hold me over (one that had a good resale value). :)
73,
Bill
AK5X




On Feb 24, 2012, at 8:05 AM, Ian Kahn wrote:

> All,
>
> I find myself finally admitting that I need an antenna tuner that supports
> high power. I run a K3/P3 combo with an Ameritron AL-811H amp. Since we
> are still waiting on word about pricing and release date for the KAT500, I
> find myself looking at other alternatives for a 1 - 1.5 KW auto tuner.
> What are others using? Several people I know have had issues with the LDG
> AT-1000PRO, so I probably want to stay away from that one.
>
> Thanks in advance for the advice.
>
> 73,
>
> -- Ian
> Ian Kahn, KM4IK
> Roswell, GA EM74ua
> km4ik.ian at gmail.com
> K3 #281, P3 #688
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:Elecraft at mailman.qth.net
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html

Bill Hammond
wham727 at aol.com
Bill Hammond-AK5X
ak5x at mac.com
ak5x at sbcglobal.net
K3 #69
P3 #817
KPA500 # 149
K2/100 #4637
K1 #2033
KX1 #1023
T1
Wayne Burdick
2012-02-24 16:32:58 UTC
Permalink
We're just making sure performance is as good as possible. (The stakes
are even higher in a QRO tuner.)

The most recent prototype worked great, in general, but on 6 meters we
felt the loss was a fraction of a dB too high. The PCB layout has
been changed to cut the RF path length and strays by a factor of two,
which should do the trick. We'll receive these boards in a week or so
and should have test results a week after that. This suggests that we
could have some field test units out in mid/late-March.

73,
Wayne
N6KR

On Feb 24, 2012, at 8:23 AM, Bill Hammond wrote:

>
> Hi Ian,
> Many of us are in that boat. I don't believe the KTA500 is
> vaperware. I'm just cooling my heals for the reason you cited,
> unreliable products from the competition. I want good products and
> great support from people that care about their customers. That is
> worth the wait, even if it is until the end of the year. Heck the
> K3 tuner will load a hairpin, I would expect the KTA500 will as
> well. If I just couldn't wait any longer ,I think I would find a
> manual tuner to hold me over (one that had a good resale value). :)
> 73,
> Bill
> AK5X
>
>
>
>
> On Feb 24, 2012, at 8:05 AM, Ian Kahn wrote:
>
>> All,
>>
>> I find myself finally admitting that I need an antenna tuner that
>> supports
>> high power. I run a K3/P3 combo with an Ameritron AL-811H amp.
>> Since we
>> are still waiting on word about pricing and release date for the
>> KAT500, I
>> find myself looking at other alternatives for a 1 - 1.5 KW auto
>> tuner.
>> What are others using? Several people I know have had issues with
>> the LDG
>> AT-1000PRO, so I probably want to stay away from that one.
>>
>> Thanks in advance for the advice.
>>
>> 73,
>>
>> -- Ian
>> Ian Kahn, KM4IK
>> Roswell, GA EM74ua
>> km4ik.ian at gmail.com
>> K3 #281, P3 #688
>> ______________________________________________________________
>> Elecraft mailing list
>> Home: http://mailman.qth.net/mailman/listinfo/elecraft
>> Help: http://mailman.qth.net/mmfaq.htm
>> Post: mailto:Elecraft at mailman.qth.net
>>
>> This list hosted by: http://www.qsl.net
>> Please help support this email list: http://www.qsl.net/donate.html
>
> Bill Hammond
> wham727 at aol.com
> Bill Hammond-AK5X
> ak5x at mac.com
> ak5x at sbcglobal.net
> K3 #69
> P3 #817
> KPA500 # 149
> K2/100 #4637
> K1 #2033
> KX1 #1023
> T1
>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:Elecraft at mailman.qth.net
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
Jim Brown
2012-02-24 16:28:41 UTC
Permalink
On 2/24/2012 6:05 AM, Ian Kahn wrote:
> What are others using? Several people I know have had issues with the LDG
> AT-1000PRO, so I probably want to stay away from that one.

I found the AT-1000 lacking and sold it when LDG could not improve it
(and kept it for three months).

I strongly recommend the Ten Tec 229 and 238 tuners, which can be bought
used for around $275 and $300 respectively. Essentially the same,
different appearance. Manual tuner, rated for legal limit. L-section
design, so they tend to produce a match with greater bandwidth than
T-section tuners. The only PITA about these tuners is the dial cord.

73, Jim K9YC.
Bruce Beford
2012-02-24 16:38:50 UTC
Permalink
Thanks for the update on the KAT500 development, Wayne. In the meantime, I'm
using an MFJ-988 satisfactorily.

73,
Bruce, N1RX

> We're just making sure performance is as good as possible. (The stakes
> are even higher in a QRO tuner.)

> The most recent prototype worked great, in general, but on 6 meters we
> felt the loss was a fraction of a dB too high. The PCB layout has
> been changed to cut the RF path length and strays by a factor of two,
> which should do the trick. We'll receive these boards in a week or so
> and should have test results a week after that. This suggests that we
> could have some field test units out in mid/late-March.

> 73,
> Wayne
> N6KR
Gary Ferdinand
2012-02-24 16:57:11 UTC
Permalink
Ian,

Unfortunately, I'm in the same boat: Looking for an antenna tuner that
*truly* supports high power. I was hoping the Palstar balanced tuner
BT1500A was it, but I found it less than robust when processing 1500 W. The
tuner (fine print) is not spec'd for 1500 continuous, so forget RTTY/etc and
beware full power tune-ups. The input balun toasts quite nicely. Also, the
relay that switches the large section of the capacitor in/out failed on me,
with the inner insulation of that relay bubbling up out of the core. The
tuner ought to run relays energized forever. Mine did not. I had left it
configured that way (ten meters) overnight. My bad, apparently. YMMV of
course.

If you ever find one that will tolerate 1.5 kW into various loads, please
post it.

FYI, I'm using that tuner to match to a 260' dipole, center fed with nominal
600-ohm OWL (constructed using Ladder Snaps).

73 and GL!

Gary W2CS





>All,
>
>I find myself finally admitting that I need an antenna tuner that
>supports high power. I run a K3/P3 combo with an Ameritron AL-811H amp.
>Since we are still waiting on word about pricing and release date for
>the KAT500, I find myself looking at other alternatives for a 1 - 1.5 KW
>auto tuner.
>What are others using? Several people I know have had issues with the
>LDG AT-1000PRO, so I probably want to stay away from that one.
>
>Thanks in advance for the advice.
>
>73,
>
>-- Ian
>Ian Kahn, KM4IK
Jim Brown
2012-02-24 17:59:24 UTC
Permalink
On 2/24/2012 8:57 AM, Gary Ferdinand wrote:
> is not spec'd for 1500 continuous, so forget RTTY/etc and
> beware full power tune-ups.

Few power amps are rated for1.5kW continuous. Yes, there are a few,
like some Alpha models. Most are rated for 1.5kW intermittent duty, and
should be de-rated by a few dB for keydown modes.

The Ten Tec tuners I mentioned fall into that category too -- indeed,
there are a few fixed caps that will release smoke when run at 1.5kW
into some loads for long periods during a contest, but those caps are
easily replaced with parts rated for more current, and the replacements
are not expensive.

Folks should be more patient with Elecraft -- they are well known for
taking enough time with engineering both at the design and manufacturing
stage to produce a product we'll be happy to own, as Wayne's recent
post in this thread clearly illustrates.

73, Jim K9YC
Gary Ferdinand
2012-02-24 19:59:23 UTC
Permalink
>-----Original Message-----
>From: elecraft-bounces at mailman.qth.net [mailto:elecraft-
>bounces at mailman.qth.net] On Behalf Of Jim Brown
>Sent: Friday, February 24, 2012 12:59 PM
>To: elecraft at mailman.qth.net
>Subject: Re: [Elecraft] high-power tuner
>
>On 2/24/2012 8:57 AM, Gary Ferdinand wrote:
>> [The Palstar BT1500A] is not spec'd for 1500 continuous, so forget
RTTY/etc and beware full
>> power tune-ups.
>
>Few power amps are rated for1.5kW continuous. Yes, there are a few,
>like some Alpha models. Most are rated for 1.5kW intermittent duty, and
>should be de-rated by a few dB for keydown modes.

My mistake, I guess. I run an Alpha 9500. A true 1.5 kW tuner is important
to me at least.

>
>The Ten Tec tuners I mentioned fall into that category too -- indeed,
>there are a few fixed caps that will release smoke when run at 1.5kW
>into some loads for long periods during a contest, but those caps are
>easily replaced with parts rated for more current, and the replacements
>are not expensive.

Good to hear. But if a tuner is advertised to handle 1500 W, it should do so
without user mods.

>
>Folks should be more patient with Elecraft -- they are well known for
>taking enough time with engineering both at the design and manufacturing
>stage to produce a product we'll be happy to own, as Wayne's recent post
>in this thread clearly illustrates.

The original poster talked about 1500 W. Is Elecraft considering such a
tuner? That would be new (and great!) news to me. For some reason I was
under the assumption it would handle around 500 W.
Eric Swartz - WA6HHQ, Elecraft
2012-02-24 20:07:15 UTC
Permalink
10:1 SWR at 500w equals the same internal antenna current and voltage in
the tuner for about a 3:1 SWR at 1500W :-)

73,

Eric
---
www.elecraft.com


On 2/24/2012 11:59 AM, Gary Ferdinand wrote:
>
>> -----Original Message-----
>> From: elecraft-bounces at mailman.qth.net [mailto:elecraft-
>> bounces at mailman.qth.net] On Behalf Of Jim Brown
>> Sent: Friday, February 24, 2012 12:59 PM
>> To: elecraft at mailman.qth.net
>> Subject: Re: [Elecraft] high-power tuner
>>
>> On 2/24/2012 8:57 AM, Gary Ferdinand wrote:
>>> [The Palstar BT1500A] is not spec'd for 1500 continuous, so forget
> RTTY/etc and beware full
>>> power tune-ups.
>> Few power amps are rated for1.5kW continuous. Yes, there are a few,
>> like some Alpha models. Most are rated for 1.5kW intermittent duty, and
>> should be de-rated by a few dB for keydown modes.
> My mistake, I guess. I run an Alpha 9500. A true 1.5 kW tuner is important
> to me at least.
>
>> The Ten Tec tuners I mentioned fall into that category too -- indeed,
>> there are a few fixed caps that will release smoke when run at 1.5kW
>> into some loads for long periods during a contest, but those caps are
>> easily replaced with parts rated for more current, and the replacements
>> are not expensive.
> Good to hear. But if a tuner is advertised to handle 1500 W, it should do so
> without user mods.
>
>> Folks should be more patient with Elecraft -- they are well known for
>> taking enough time with engineering both at the design and manufacturing
>> stage to produce a product we'll be happy to own, as Wayne's recent post
>> in this thread clearly illustrates.
> The original poster talked about 1500 W. Is Elecraft considering such a
> tuner? That would be new (and great!) news to me. For some reason I was
> under the assumption it would handle around 500 W.
>
>
>
>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:Elecraft at mailman.qth.net
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
Greg Beat
2012-02-24 18:09:29 UTC
Permalink
Ian -

I have been watching product developments

I this power/automatic operation category:



Palstar HF-AUTO

http://www.palstar.com/hf-auto.php



RF Concepts/Alpha 4040 Automatic Tuner

http://www.rfconcepts.com/PRODUCTS/New-Products/Alpha4040



E-Z Tuner - Jim Garland, W8ZR

(2002 QST article and ARRL Handbooks)

http://www.w8zr.net/eztuner/index.htm



I made a suggestion to Steve at RF Concepts, a couple of years ago,

when RF Concepts was planning a high-power HF automatic tuner.

They needed to incorporate more uProcessor/controller power (since W8ZR
Basic Stamp)

in their planned offering, since the state-of-art has progressed since 2002.

They did, using Linux kernel with the Beagleboard XM



The Palstar and RF Concepts/Alpha offerings are INDOOR tuners.

I have a preference to have the tuner outdoors at the antennas

or feedpoints (like commercial broadcasters).

==

IF Wayne, N6NR is coming to Dayton -

it would be nice to SEE one of the KAT500 prototypes



==

Greg, w9gb



=== previous message ===

Date: Fri, 24 Feb 2012 08:32:58 -0800

From: Wayne Burdick <n6kr at elecraft.com>

Subject: Re: [Elecraft] high-power tuner

To: Bill Hammond <wham727 at aol.com>



> We're just making sure performance is as good as possible. (The stakes

> are even higher in a QRO tuner.)

>

> The most recent prototype worked great, in general, but on 6 meters we

> felt the loss was a fraction of a dB too high. The PCB layout has

> been changed to cut the RF path length and strays by a factor of two,

> which should do the trick. We'll receive these boards in a week or so

> and should have test results a week after that. This suggests that we

> could have some field test units out in mid/late-March.

>

> 73,Wayne - N6KR
Ian Kahn
2012-02-24 18:32:28 UTC
Permalink
Wayne, thank you for the update on the KAT500 progress. While I won't be
at Dayton, I, too, would love to see at least photos of the prototype
posted to the web site.

All others - Thank you for the suggestions. Fortuitously, I actually was
offered, at no charge, a legal limit manual inductor roller tuner. Since
this one is free, I'll take it and bide my time until Wayne, Eric, and
Company release the KAT500.

73,

--Ian
Ian Kahn, KM4IK
Roswell, GA EM74ua
km4ik.ian at gmail.com
K3 #281, P3 #688



On Fri, Feb 24, 2012 at 1:09 PM, Greg Beat <gregory.beat at comcast.net> wrote:

> Ian -
>
> I have been watching product developments
>
> I this power/automatic operation category:
>
>
>
> Palstar HF-AUTO
>
> http://www.palstar.com/hf-auto.php
>
>
>
> RF Concepts/Alpha 4040 Automatic Tuner
>
> http://www.rfconcepts.com/PRODUCTS/New-Products/Alpha4040
>
>
>
> E-Z Tuner - Jim Garland, W8ZR
>
> (2002 QST article and ARRL Handbooks)
>
> http://www.w8zr.net/eztuner/index.htm
>
>
>
> I made a suggestion to Steve at RF Concepts, a couple of years ago,
>
> when RF Concepts was planning a high-power HF automatic tuner.
>
> They needed to incorporate more uProcessor/controller power (since W8ZR
> Basic Stamp)
>
> in their planned offering, since the state-of-art has progressed since
> 2002.
>
> They did, using Linux kernel with the Beagleboard XM
>
>
>
> The Palstar and RF Concepts/Alpha offerings are INDOOR tuners.
>
> I have a preference to have the tuner outdoors at the antennas
>
> or feedpoints (like commercial broadcasters).
>
> ==
>
> IF Wayne, N6NR is coming to Dayton -
>
> it would be nice to SEE one of the KAT500 prototypes
>
>
>
> ==
>
> Greg, w9gb
>
>
>
> === previous message ===
>
> Date: Fri, 24 Feb 2012 08:32:58 -0800
>
> From: Wayne Burdick <n6kr at elecraft.com>
>
> Subject: Re: [Elecraft] high-power tuner
>
> To: Bill Hammond <wham727 at aol.com>
>
>
>
> > We're just making sure performance is as good as possible. (The stakes
>
> > are even higher in a QRO tuner.)
>
> >
>
> > The most recent prototype worked great, in general, but on 6 meters we
>
> > felt the loss was a fraction of a dB too high. The PCB layout has
>
> > been changed to cut the RF path length and strays by a factor of two,
>
> > which should do the trick. We'll receive these boards in a week or so
>
> > and should have test results a week after that. This suggests that we
>
> > could have some field test units out in mid/late-March.
>
> >
>
> > 73,Wayne - N6KR
>
>
>
>
>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:Elecraft at mailman.qth.net
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
>



--
Phil &amp; Debbie Salas
2012-02-24 20:07:52 UTC
Permalink
I've had a MFJ-998 autotuner for about 3.5 years now. It works great, and
it is easy to upgrade its software (a new upgrade just became available).
The most power I've put through it is 1200 watts feeding my 43-foot
vertical, though now I'm only using it with my KPA500. I have a review on
my website at www.ad5x.com, as well as a mod whereby it feeds the
amp-disable input on my KPA500 when it tunes.

Phil - AD5X
W5RDW
2012-03-01 18:16:19 UTC
Permalink
Ditto on the MFJ-998 autotuner. I have had mine a few years and now use it
with the KPA500. It has matched anything I have thrown at it. A little on
the noisy side when it gets a hold of a load it has to work on a little, but
it has always done what I want it to do.

-----
Roger W5RDW
--
View this message in context: http://elecraft.365791.n2.nabble.com/high-power-tuner-tp7314904p7333509.html
Sent from the Elecraft mailing list archive at Nabble.com.
David Gilbert
2012-03-01 19:25:08 UTC
Permalink
Just curious ... have you ever measured the loss in the tuner? Most of
the MFJ tuners tend to rank pretty low in that respect. Presenting a
usable load to the amplifier does not in itself make it a good tuner.

73,
Dave AB7E



On 3/1/2012 11:16 AM, W5RDW wrote:
> Ditto on the MFJ-998 autotuner. I have had mine a few years and now use it
> with the KPA500. It has matched anything I have thrown at it. A little on
> the noisy side when it gets a hold of a load it has to work on a little, but
> it has always done what I want it to do.
>
> -----
> Roger W5RDW
Tony Estep
2012-03-01 21:15:50 UTC
Permalink
On Thu, Mar 1, 2012 at 1:25 PM, David Gilbert <xdavid at cis-broadband.com> wrote:
>...Most of the MFJ tuners tend to rank pretty low ...
===========
QST hasn't reviewed the 998, but they did have a review of the MFJ 994
back in 2006. Tested across all bands and a range of impedances, it
generally showed lower losses than the other similar autotuners
tested, made by Palstar and LDG. There is a mini-review of the 998 by
list member AD5X at:

http://www.ad5x.com/images/Presentations/MFJ998%20Review%20RevA.pdf

but it doesn't include loss measurements. Other than the loss
measurements for the 994 mentioned above, which looked pretty good, I
can't find any other measured results for MFJ auto-tuners.

Tony KT0NY



--
http://www.isb.edu/faculty/facultydir.aspx?ddlFaculty=352
W5RDW
2012-03-09 22:10:16 UTC
Permalink
Never had any reason to wonder if my MFJ-998 has more than normal loss. It
hasn't let any smoke out of the cabinet yet! I use to run a Drake L-7 thru
it, but now use the KPA500 all the time and have retired the Drake.

> /Most of the MFJ tuners tend to rank pretty low in that respect./

Dave, I'd be interested in reading about the info you have on the MFJ tuner
loss.

-----
Roger W5RDW
--
View this message in context: http://elecraft.365791.n2.nabble.com/high-power-tuner-tp7314904p7359740.html
Sent from the Elecraft mailing list archive at Nabble.com.
WILLIS COOKE
2012-03-09 22:24:47 UTC
Permalink
I wonder how those that claim a certain efficiency for a MFJ-998 or any other antenna matching device are measuring the output power. ?No watt meter that I know including the famous and antique Bird can measure power with any degree of accuracy unless the load is very near the nominal value (usually 50 ohms). ?If you need a tuner, your antenna does not meet this criteria so, what are you using to form your opinion? ?I suppose that you could compare two tuners for a relative efficiency by using the same transmitter and antenna and a field strength meter. ?Of course, if you are running near the rated power, you can watch for smoke and get a one time opinion that the device was not efficient enough to survive.
?
Willis 'Cookie' Cooke
K5EWJ & Trustee N5BPS, USS Cavalla, USS Stewart


________________________________
From: W5RDW <rwhitetexas at verizon.net>
To: elecraft at mailman.qth.net
Sent: Friday, March 9, 2012 4:10 PM
Subject: Re: [Elecraft] high-power tuner

Never had any reason to wonder if my MFJ-998 has more than normal loss. It
hasn't let any smoke out of the cabinet yet! I use to run a Drake L-7 thru
it, but now use the KPA500 all the time and have retired the Drake.

> /Most of the MFJ tuners tend to rank pretty low in that respect./

Dave, I'd be interested in reading about the info you have on the MFJ tuner
loss.

-----
Roger W5RDW
--
View this message in context: http://elecraft.365791.n2.nabble.com/high-power-tuner-tp7314904p7359740.html
Sent from the Elecraft mailing list archive at Nabble.com.
______________________________________________________________
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Tony Estep
2012-03-09 23:01:37 UTC
Permalink
On Fri, Mar 9, 2012 at 4:24 PM, WILLIS COOKE <wrcooke at yahoo.com> wrote:
> I wonder how those that claim a certain efficiency for a MFJ-998 or any other antenna matching device are measuring the output power....
============
Cookie, the ARRL labs have some way of doing this, but in their
reviews of tuners they don't explain how they do it. I suppose they
have some scheme for measuring what goes in and what comes out, but
they don't say. However, as I mentioned in a previous post, the MFJ
994 tuner they tested (August 2006) had somewhat lower losses than the
other similar tuners in the review. I could not find any published
data to support the assertion that MFJ tuners have high losses.

Tony KT0NY



--
http://www.isb.edu/faculty/facultydir.aspx?ddlFaculty=352
Mike WA8BXN
2012-03-09 23:03:00 UTC
Permalink
I can think of a few ways to investigate a tuner's efficiency. Google
searching can probably give more.

You can read the inductor and capacitor values selected by the 998 and then
do a circuit simulation of the L network and determine current through the
inductors to find their ohmic losses.

Second, you can connect known non-inductive resistors (of different values,
throw in some inductance or capacitance too) as the output load and then
with an RF voltmeter determine the voltage across the load and then
calculate the power out. You will have to calculate the phase angle of your
load as well if its not purely resistive. This method could be done using
low power so its easier to build the output loads.

You could probably also measure the temperature rise of the tuner in
operation (put it in an insulated box).

Granted, there may not be a simple off the self instrument to do it, but it
can be done!

73 - Mike WA8BXN




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

From: WILLIS COOKE
Date: 3/9/2012 5:31:30 PM
To: W5RDW; elecraft at mailman.qth.net
Subject: Re: [Elecraft] high-power tuner

I wonder how those that claim a certain efficiency for a MFJ-998 or any
other antenna matching device are measuring the output power. No watt meter
that I know including the famous and antique Bird can measure power with any
degree of accuracy unless the load is very near the nominal value (usually
50 ohms). If you need a tuner, your antenna does not meet this criteria so,
what are you using to form your opinion? I suppose that you could compare
two tuners for a relative efficiency by using the same transmitter and
antenna and a field strength meter. Of course, if you are running near the
rated power, you can watch for smoke and get a one time opinion that the
device was not efficient enough to survive.

Willis 'Cookie' Cooke
K5EWJ & Trustee N5BPS, USS Cavalla, USS Stewart
Fred Jensen
2012-03-09 23:14:40 UTC
Permalink
On 3/9/2012 2:24 PM, WILLIS COOKE wrote:

> If you need a tuner, your
> antenna does not meet this criteria so, what are you using to form
> your opinion?

Weigh the tuner, then transmit continuously, measure the temperature
rise, and when it's stable, calculate the heat loss [something to do
with Boltzman's Constant -- the tuner *is* painted black]. What doesn't
leave as heat must leave as RF. Did it years ago on a 10 KW FM
broadcast transmitter [4 ea 4-1000's], and it came within one percent of
the efficiency measured with the water-cooled dummy load. YMMV however.

73,

Fred K6DGW
- Northern California Contest Club
- CU in the 2012 Cal QSO Party 6-7 Oct 2012
- www.cqp.org
Ian Kahn - Ham
2012-03-09 23:30:43 UTC
Permalink
This probably shows my gross lack of knowledge of the physics involved
here, but what does the weight of the tuner have to do with its efficiency?

73,

--Ian

Ian Kahn, KM4IK
Roswell, GA
km4ik.ian at gmail.com
K3 #281, P3 #688


On 3/9/2012 6:14 PM, Fred Jensen wrote:
> On 3/9/2012 2:24 PM, WILLIS COOKE wrote:
>
>> If you need a tuner, your
>> antenna does not meet this criteria so, what are you using to form
>> your opinion?
> Weigh the tuner, then transmit continuously, measure the temperature
> rise, and when it's stable, calculate the heat loss [something to do
> with Boltzman's Constant -- the tuner *is* painted black]. What doesn't
> leave as heat must leave as RF. Did it years ago on a 10 KW FM
> broadcast transmitter [4 ea 4-1000's], and it came within one percent of
> the efficiency measured with the water-cooled dummy load. YMMV however.
>
> 73,
>
> Fred K6DGW
> - Northern California Contest Club
> - CU in the 2012 Cal QSO Party 6-7 Oct 2012
> - www.cqp.org
>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:Elecraft at mailman.qth.net
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
Rick Bates
2012-03-10 00:06:28 UTC
Permalink
I'll take a guess...

You have to know the mass to find the amount of energy converted into heat.
Like Ohm's law, given two values, you can figure out the third. If you know
the mass and know the temperature change, you can calculate the energy.

Ok Fred, am I close?

Rick wa6nhc

-----Original Message-----
From: Ian Kahn - Ham

This probably shows my gross lack of knowledge of the physics involved
here, but what does the weight of the tuner have to do with its efficiency?

73,

--Ian

Ian Kahn, KM4IK
Roswell, GA
km4ik.ian at gmail.com
K3 #281, P3 #688


On 3/9/2012 6:14 PM, Fred Jensen wrote:
> On 3/9/2012 2:24 PM, WILLIS COOKE wrote:
>
>> If you need a tuner, your
>> antenna does not meet this criteria so, what are you using to form
>> your opinion?
> Weigh the tuner, then transmit continuously, measure the temperature
> rise, and when it's stable, calculate the heat loss [something to do
> with Boltzman's Constant -- the tuner *is* painted black]. What doesn't
> leave as heat must leave as RF. Did it years ago on a 10 KW FM
> broadcast transmitter [4 ea 4-1000's], and it came within one percent of
> the efficiency measured with the water-cooled dummy load. YMMV however.
>
> 73,
>
> Fred K6DGW
> - Northern California Contest Club
> - CU in the 2012 Cal QSO Party 6-7 Oct 2012
> - www.cqp.org
>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:Elecraft at mailman.qth.net
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
______________________________________________________________
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Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Elecraft at mailman.qth.net

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Mike WA8BXN
2012-03-10 00:17:28 UTC
Permalink
Ian,

Weight comes into play in two ways. A heavier tuner will likely have less
loss due to less resistive loss by using larger diameter wire etc. But that
s not the issue in measuring the loss.

As Fred mentions below, power fed into a tuner goes two places. One is out
to the load (antenna) and the other is heating the tuner (not a good thing).
One can measure how much a tuner warms up during use, that's due to loss in
the tuner. Just knowing the temperature change doesn't give the full answer
though. Lets say we measure an increased temperature of 10 degrees. Now if
we have a very heavy tuner, that would be more power lost in the tuner than
in a tuner that has the same 10 degree increase but is very small. Look at
it this way. It would take a lot more power to heat a gallon of water 10
degrees than to head a drop of water 10 degrees.

To calculate the actual power loss in the tuner you would have to use the
right degree units, the right weight (mass) units and constants. You would
also have to heat insulate the tuner from the room so it doesn't cool off
during your measurement period.

73 - Mike WA8BXN





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

From: Ian Kahn - Ham
Date: 3/9/2012 6:31:37 PM
To: k6dgw at foothill.net
Cc: elecraft at mailman.qth.net
Subject: Re: [Elecraft] high-power tuner

This probably shows my gross lack of knowledge of the physics involved
Here, but what does the weight of the tuner have to do with its efficiency?

73,

--Ian

Ian Kahn, KM4IK
Roswell, GA
km4ik.ian at gmail.com
K3 #281, P3 #688


On 3/9/2012 6:14 PM, Fred Jensen wrote:
> On 3/9/2012 2:24 PM, WILLIS COOKE wrote:
>
>> If you need a tuner, your
>> antenna does not meet this criteria so, what are you using to form
>> your opinion?
> Weigh the tuner, then transmit continuously, measure the temperature
> rise, and when it's stable, calculate the heat loss [something to do
> with Boltzman's Constant -- the tuner *is* painted black]. What doesn't
> leave as heat must leave as RF. Did it years ago on a 10 KW FM
> broadcast transmitter [4 ea 4-1000's], and it came within one percent of
> the efficiency measured with the water-cooled dummy load. YMMV however.
>
> 73,
>
> Fred K6DGW
> - Northern California Contest Club
> - CU in the 2012 Cal QSO Party 6-7 Oct 2012
> - www.cqp.org
Tony Estep
2012-03-10 01:01:09 UTC
Permalink
On Fri, Mar 9, 2012 at 5:30 PM, Ian Kahn - Ham <km4ik.ian at gmail.com> wrote:
> This probably shows my gross lack of knowledge of the physics involved
> here, but what does the weight of the tuner have to do with its efficiency...
=============
Ian, the idea was to measure the power soaked up by the tuner by
measuring how fast it heats up. To turn degrees/second into a measure
of power, you gotta know how much mass was getting heated.

Tony KT0NY


--
http://www.isb.edu/faculty/facultydir.aspx?ddlFaculty=352
WILLIS COOKE
2012-03-10 02:43:13 UTC
Permalink
OK Guys, I have a Physics Degree too, but realistically, if the tuner uses real coils and air capacitors like the Matchbox it is really efficient. ?If it uses link coupling like we did in olden days it is probably a scotch (technical term meaning a little bit) better than the more common T network. ?If it uses toroids, small fixed capacitors and relay switching, it probably has even more loss. ?So, maybe the answer is to buy a tuner that is the same size as your amplifier. ?If you elect to run a KTA-500 you probably are not terribly concerned whether you get 475 watts to the antenna or 450 watts. ?If you need an Alpha 9500 to be sure that you get through then you need the Alpha 4040 so it will look great near your 9500 and the 3 grand price will seem cheap after paying 8 grand for the amp. ?You can always brag on your 75 meter net that of the 1499.9 watts out of the 9500 1499.8 watts get through the 4040 to melt the RG8X that feeds your Buddy Pole.
?But, if the KTA-500 is your thing then a tuner that costs more than your amp and is the biggest thing in your shack (unless you have a left over BC-610) will look pretty silly.

If you must measure your temperatures to figure your efficiency down to the milliwatt, be sure and use RTDs for measurement because thermocouples are not nearly accurate enough for precision measurements.
?
Willis 'Cookie' Cooke
K5EWJ & Trustee N5BPS, USS Cavalla, USS Stewart


________________________________
From: Tony Estep <esteptony at gmail.com>
To: Elecraft <elecraft at mailman.qth.net>
Sent: Friday, March 9, 2012 7:01 PM
Subject: Re: [Elecraft] high-power tuner

On Fri, Mar 9, 2012 at 5:30 PM, Ian Kahn - Ham <km4ik.ian at gmail.com> wrote:
> This probably shows my gross lack of knowledge of the physics involved
> here, but what does the weight of the tuner have to do with its efficiency...
=============
Ian, the idea was to measure the power soaked up by the tuner by
measuring how fast it heats up. To turn degrees/second into a measure
of power, you gotta know how much mass was getting heated.

Tony KT0NY


--
http://www.isb.edu/faculty/facultydir.aspx?ddlFaculty=352
______________________________________________________________
Elecraft mailing list
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Help: http://mailman.qth.net/mmfaq.htm
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Mike WA8BXN
2012-03-10 03:22:52 UTC
Permalink
I'm not convinced that toroids are inferior to air wound coils. There will
be some core loss but there will be less ohmic loss as well. I'm also not
sure that just getting a tuner rated at the same power level as an amplifier
is always going to be most efficient. If the marketing agency is doing the
tuner rating the rating may be suspect.

There are some tuners that can just about match anything for an antenna. If
it won't melt at a particular power level, is it the best tuner for that
power level? Matching a given load usually means giving the transmitter near
a 50 ohm load. If you have a tuner that does that with no antenna attached
it means the tuner must dissipate all the power.

Manual tuners often have some hints on how to get the best efficiency at a
good match, like try to find a match using maximum or minimum value for
control X. With automatic tuners, we often just let the tuner do its thing
and use the match it finds. Some tuners will have better algorithms than
others in picking the best match. The difference from one tuner to another
can be a lot more than milliwatts. So it can be a good idea to get good
evaluations of available tuners.

73 - Mike WA8BXN




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

From: WILLIS COOKE
Date: 3/9/2012 9:47:31 PM
To: Elecraft
Subject: Re: [Elecraft] high-power tuner

OK Guys, I have a Physics Degree too, but realistically, if the tuner uses
real coils and air capacitors like the Matchbox it is really efficient. If
it uses link coupling like we did in olden days it is probably a scotch
(technical term meaning a little bit) better than the more common T network.
If it uses toroids, small fixed capacitors and relay switching, it probably
has even more loss. So, maybe the answer is to buy a tuner that is the same
size as your amplifier. If you elect to run a KTA-500 you probably are not
terribly concerned whether you get 475 watts to the antenna or 450 watts. If
you need an Alpha 9500 to be sure that you get through then you need the
Alpha 4040 so it will look great near your 9500 and the 3 grand price will
seem cheap after paying 8 grand for the amp. You can always brag on your 75
meter net that of the 1499.9 watts out of the 9500 1499.8 watts get through
the 4040 to melt the RG8X that feeds your Buddy Pole.
But, if the KTA-500 is your thing then a tuner that costs more than your amp
and is the biggest thing in your shack (unless you have a left over BC-610)
will look pretty silly.

If you must measure your temperatures to figure your efficiency down to the
milliwatt, be sure and use RTDs for measurement because thermocouples are
not nearly accurate enough for precision measurements.

Willis 'Cookie' Cooke
K5EWJ & Trustee N5BPS, USS Cavalla, USS Stewart
Don Wilhelm
2012-03-10 04:55:00 UTC
Permalink
Mike and all,

The T-Network tuners are problematic even though they can be quite
wide-range - they may show multiple tuning condition for any given
antenna/matching situation. They should always be adjusted for the
largest value of capacity that will tune properly.

Most automatic tuners are of the L network type which avoids the
ambiguous tuning spots of the T-network tuners.

73,
Don W3FPR

On 3/9/2012 10:22 PM, Mike WA8BXN wrote:
>
> I'm not convinced that toroids are inferior to air wound coils. There will
> be some core loss but there will be less ohmic loss as well. I'm also not
> sure that just getting a tuner rated at the same power level as an amplifier
> is always going to be most efficient. If the marketing agency is doing the
> tuner rating the rating may be suspect.
>
> There are some tuners that can just about match anything for an antenna. If
> it won't melt at a particular power level, is it the best tuner for that
> power level? Matching a given load usually means giving the transmitter near
> a 50 ohm load. If you have a tuner that does that with no antenna attached
> it means the tuner must dissipate all the power.
>
> Manual tuners often have some hints on how to get the best efficiency at a
> good match, like try to find a match using maximum or minimum value for
> control X. With automatic tuners, we often just let the tuner do its thing
> and use the match it finds. Some tuners will have better algorithms than
> others in picking the best match. The difference from one tuner to another
> can be a lot more than milliwatts. So it can be a good idea to get good
> evaluations of available tuners.
>
> 73 - Mike WA8BXN
>
>
>
>
> -------Original Message-------
>
> From: WILLIS COOKE
> Date: 3/9/2012 9:47:31 PM
> To: Elecraft
> Subject: Re: [Elecraft] high-power tuner
>
> OK Guys, I have a Physics Degree too, but realistically, if the tuner uses
> real coils and air capacitors like the Matchbox it is really efficient. If
> it uses link coupling like we did in olden days it is probably a scotch
> (technical term meaning a little bit) better than the more common T network.
> If it uses toroids, small fixed capacitors and relay switching, it probably
> has even more loss. So, maybe the answer is to buy a tuner that is the same
> size as your amplifier. If you elect to run a KTA-500 you probably are not
> terribly concerned whether you get 475 watts to the antenna or 450 watts. If
> you need an Alpha 9500 to be sure that you get through then you need the
> Alpha 4040 so it will look great near your 9500 and the 3 grand price will
> seem cheap after paying 8 grand for the amp. You can always brag on your 75
> meter net that of the 1499.9 watts out of the 9500 1499.8 watts get through
> the 4040 to melt the RG8X that feeds your Buddy Pole.
> But, if the KTA-500 is your thing then a tuner that costs more than your amp
> and is the biggest thing in your shack (unless you have a left over BC-610)
> will look pretty silly.
>
> If you must measure your temperatures to figure your efficiency down to the
> milliwatt, be sure and use RTDs for measurement because thermocouples are
> not nearly accurate enough for precision measurements.
>
> Willis 'Cookie' Cooke
> K5EWJ& Trustee N5BPS, USS Cavalla, USS Stewart
>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:Elecraft at mailman.qth.net
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
>
David Gilbert
2012-03-10 07:13:48 UTC
Permalink
A T-Network tuner with a large enough capacitor in one leg set to full
capacity is essentially an L-network tuner.

73,
Dave AB7E



On 3/9/2012 9:55 PM, Don Wilhelm wrote:
> Mike and all,
>
> The T-Network tuners are problematic even though they can be quite
> wide-range - they may show multiple tuning condition for any given
> antenna/matching situation. They should always be adjusted for the
> largest value of capacity that will tune properly.
>
> Most automatic tuners are of the L network type which avoids the
> ambiguous tuning spots of the T-network tuners.
>
> 73,
> Don W3FPR
>
> On 3/9/2012 10:22 PM, Mike WA8BXN wrote:
>> I'm not convinced that toroids are inferior to air wound coils. There will
>> be some core loss but there will be less ohmic loss as well. I'm also not
>> sure that just getting a tuner rated at the same power level as an amplifier
>> is always going to be most efficient. If the marketing agency is doing the
>> tuner rating the rating may be suspect.
>>
>> There are some tuners that can just about match anything for an antenna. If
>> it won't melt at a particular power level, is it the best tuner for that
>> power level? Matching a given load usually means giving the transmitter near
>> a 50 ohm load. If you have a tuner that does that with no antenna attached
>> it means the tuner must dissipate all the power.
>>
>> Manual tuners often have some hints on how to get the best efficiency at a
>> good match, like try to find a match using maximum or minimum value for
>> control X. With automatic tuners, we often just let the tuner do its thing
>> and use the match it finds. Some tuners will have better algorithms than
>> others in picking the best match. The difference from one tuner to another
>> can be a lot more than milliwatts. So it can be a good idea to get good
>> evaluations of available tuners.
>>
>> 73 - Mike WA8BXN
>>
>>
>>
>>
>> -------Original Message-------
>>
>> From: WILLIS COOKE
>> Date: 3/9/2012 9:47:31 PM
>> To: Elecraft
>> Subject: Re: [Elecraft] high-power tuner
>>
>> OK Guys, I have a Physics Degree too, but realistically, if the tuner uses
>> real coils and air capacitors like the Matchbox it is really efficient. If
>> it uses link coupling like we did in olden days it is probably a scotch
>> (technical term meaning a little bit) better than the more common T network.
>> If it uses toroids, small fixed capacitors and relay switching, it probably
>> has even more loss. So, maybe the answer is to buy a tuner that is the same
>> size as your amplifier. If you elect to run a KTA-500 you probably are not
>> terribly concerned whether you get 475 watts to the antenna or 450 watts. If
>> you need an Alpha 9500 to be sure that you get through then you need the
>> Alpha 4040 so it will look great near your 9500 and the 3 grand price will
>> seem cheap after paying 8 grand for the amp. You can always brag on your 75
>> meter net that of the 1499.9 watts out of the 9500 1499.8 watts get through
>> the 4040 to melt the RG8X that feeds your Buddy Pole.
>> But, if the KTA-500 is your thing then a tuner that costs more than your amp
>> and is the biggest thing in your shack (unless you have a left over BC-610)
>> will look pretty silly.
>>
>> If you must measure your temperatures to figure your efficiency down to the
>> milliwatt, be sure and use RTDs for measurement because thermocouples are
>> not nearly accurate enough for precision measurements.
>>
>> Willis 'Cookie' Cooke
>> K5EWJ& Trustee N5BPS, USS Cavalla, USS Stewart
>>
>> ______________________________________________________________
>> Elecraft mailing list
>> Home: http://mailman.qth.net/mailman/listinfo/elecraft
>> Help: http://mailman.qth.net/mmfaq.htm
>> Post: mailto:Elecraft at mailman.qth.net
>>
>> This list hosted by: http://www.qsl.net
>> Please help support this email list: http://www.qsl.net/donate.html
>>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:Elecraft at mailman.qth.net
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
>
Rick Stealey
2012-03-10 13:17:39 UTC
Permalink
There seems to have been no answer as to how to accurately measure the loss in a tuner.
Here is a solution but requires two tuners or at least one calibrated one that could be
used to measure others.
Take first tuner and tune it into the mismatch, say 600 ohms. Use an antenna analyzer.
Then remove the load, and connect another tuner to the output of the first (back-
to-back - antenna port on first to antenna port on second tuner.) Then put a 50 ohm
load on the second tuner where the transceiver would be connected, and tune the second
tuner to a match. It will have the same settings as the first tuner, complete symmetry.
Then measure the power in the 50 ohm load to get the loss.

Since both tuners are matching the same load, and the system is symmetrical the
loss contribution by each tuner is half. Repeat for other types of loads, and now
you have a calibrated tuner to use with any tuner you want to test.

Rick K2XT
Ron D'Eau Claire
2012-03-10 18:46:45 UTC
Permalink
I was investigating tuner losses a few years ago and ran into many of these
same questions.

A physicist buddy pointed out to me that the normal approach to measure loss
in something like a tuner is to put it in a well-insulated chamber and
measure the rise in temperature over time while transmitting. From there on
can calculate the energy required to cause the temperature rise which can be
used to calculate the number of watts of RF that never make it through the
box.

73, Ron AC7AC

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

There seems to have been no answer as to how to accurately measure the loss
in a tuner.
Here is a solution but requires two tuners or at least one calibrated one
that could be used to measure others.
Take first tuner and tune it into the mismatch, say 600 ohms. Use an
antenna analyzer.
Then remove the load, and connect another tuner to the output of the first
(back- to-back - antenna port on first to antenna port on second tuner.)
Then put a 50 ohm load on the second tuner where the transceiver would be
connected, and tune the second tuner to a match. It will have the same
settings as the first tuner, complete symmetry.
Then measure the power in the 50 ohm load to get the loss.

Since both tuners are matching the same load, and the system is symmetrical
the loss contribution by each tuner is half. Repeat for other types of
loads, and now you have a calibrated tuner to use with any tuner you want to
test.

Rick K2XT
Erik Basilier
2012-03-10 20:31:25 UTC
Permalink
As has been clearly demonstrated in this thread, there are multiple methods
of measurement. The one that gets my vote for elegance is the one with two
tuners back-to-back. With respect to the method that measures temperature
rise, taking into account the mass of the tuner, one also needs to take into
account the specific heat capacity of the tuner. One kilo of material x
doesn't heat up at the same rate as one kilo of material y when the same
heating power is applied. The tuner will of course be a mix of materials, so
one would have to measure the rate at which the tuner heats up when heat is
applied through a know heating source rather than TX power. If it is done
that way, one needs to know neither the mass nor the specific heat capacity,
since what one is measuring is essentially the mass times the specific heat
capacity.

73, Erik K7TV

-----Original Message-----
From: elecraft-bounces at mailman.qth.net
[mailto:elecraft-bounces at mailman.qth.net] On Behalf Of Ron D'Eau Claire
Sent: Saturday, March 10, 2012 11:47 AM
To: 'Rick Stealey'; elecraft at mailman.qth.net
Subject: Re: [Elecraft] high-power tuner

I was investigating tuner losses a few years ago and ran into many of these
same questions.

A physicist buddy pointed out to me that the normal approach to measure loss
in something like a tuner is to put it in a well-insulated chamber and
measure the rise in temperature over time while transmitting. From there on
can calculate the energy required to cause the temperature rise which can be
used to calculate the number of watts of RF that never make it through the
box.

73, Ron AC7AC

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

There seems to have been no answer as to how to accurately measure the loss
in a tuner.
Here is a solution but requires two tuners or at least one calibrated one
that could be used to measure others.
Take first tuner and tune it into the mismatch, say 600 ohms. Use an
antenna analyzer.
Then remove the load, and connect another tuner to the output of the first
(back- to-back - antenna port on first to antenna port on second tuner.)
Then put a 50 ohm load on the second tuner where the transceiver would be
connected, and tune the second tuner to a match. It will have the same
settings as the first tuner, complete symmetry.
Then measure the power in the 50 ohm load to get the loss.

Since both tuners are matching the same load, and the system is symmetrical
the loss contribution by each tuner is half. Repeat for other types of
loads, and now you have a calibrated tuner to use with any tuner you want to
test.

Rick K2XT

______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Elecraft at mailman.qth.net

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Vic K2VCO
2012-03-10 21:11:16 UTC
Permalink
I've recently been experimenting with tuners. I have a "275 watt" Johnson Matchbox (which
is actually good for more than a kW on CW in most cases) and a huge T network that I just
built with a massive edge-wound rotary inductor and capacitors with air gaps of about 3/8"
(near 10mm). The T network has a DX Engineering "5 kW" rated 1:1 balun on the output.

The antenna is an 88-foot dipole fed with 500 ohm open-wire line and some 450-ohm ladder line.

I can switch between these tuners instantly. On 40 meter received signals I can detect
absolutely no difference in signal strength. The T network is adjusted for the least
possible inductance that gives a 1:1 SWR, and the output capacitor is at maximum (300 pf
air plus 300 pf ceramic padder)..

There is also no difference in noise level. If one of the tuners provided better balance,
one would expect that there would be less noise pickup on the feedline. But I don't see this.

One anomalous result: there is a weak unstable carrier that I can hear on the Matchbox but
not on the T network. I have verified that this is not a birdie, but an actual signal. It
could be attributed to feedline pickup -- but wouldn't you expect the matchbox to be
better in this regard? I'm investigating further.

On 3/10/2012 12:31 PM, Erik Basilier wrote:
> As has been clearly demonstrated in this thread, there are multiple methods
> of measurement. The one that gets my vote for elegance is the one with two
> tuners back-to-back. With respect to the method that measures temperature
> rise, taking into account the mass of the tuner, one also needs to take into
> account the specific heat capacity of the tuner. One kilo of material x
> doesn't heat up at the same rate as one kilo of material y when the same
> heating power is applied. The tuner will of course be a mix of materials, so
> one would have to measure the rate at which the tuner heats up when heat is
> applied through a know heating source rather than TX power. If it is done
> that way, one needs to know neither the mass nor the specific heat capacity,
> since what one is measuring is essentially the mass times the specific heat
> capacity.
>
> 73, Erik K7TV
l

--
Vic, K2VCO
Fresno CA
http://www.qsl.net/k2vco/
Vic K2VCO
2012-03-10 21:38:14 UTC
Permalink
I just did the following experiment: I coupled a grid-dip oscillator to my feed line far
from the tuners and switching relays. I put it a few inches from the feedline equidistant
from the conductors. I found that the T network plus DXE balun reduced the signal pickup
by about 15 dB over the Matchbox!

That means that both radiation and noise pickup on the feedline are much less with the T
than with the Matchbox. At the same time I verified that there was no detectable
difference between the strength of received signals coming from the antenna.

This is amazing! It means that the T network and balun is significantly better than the
Matchbox in this important respect. So much for mythology.

On 3/10/2012 1:11 PM, Vic K2VCO wrote:
> I've recently been experimenting with tuners. I have a "275 watt" Johnson Matchbox
> (which is actually good for more than a kW on CW in most cases) and a huge T network
> that I just built with a massive edge-wound rotary inductor and capacitors with air gaps
> of about 3/8" (near 10mm). The T network has a DX Engineering "5 kW" rated 1:1 balun on
> the output.
>
> The antenna is an 88-foot dipole fed with 500 ohm open-wire line and some 450-ohm ladder
> line.
>
> I can switch between these tuners instantly. On 40 meter received signals I can detect
> absolutely no difference in signal strength. The T network is adjusted for the least
> possible inductance that gives a 1:1 SWR, and the output capacitor is at maximum (300 pf
> air plus 300 pf ceramic padder)..
>
> There is also no difference in noise level. If one of the tuners provided better
> balance, one would expect that there would be less noise pickup on the feedline. But I
> don't see this.
>
> One anomalous result: there is a weak unstable carrier that I can hear on the Matchbox
> but not on the T network. I have verified that this is not a birdie, but an actual
> signal. It could be attributed to feedline pickup -- but wouldn't you expect the
> matchbox to be better in this regard? I'm investigating further.
>
> --
> Vic, K2VCO
> Fresno CA
> http://www.qsl.net/k2vco/
Don Wilhelm
2012-03-11 00:06:32 UTC
Permalink
Vic,

Be aware that loss in the tuner can reduce the signal pickup - I would
not be so quick to pass judgement that the Matchbox is less efficient
than the T-network tuner - I know the link coupled tuner (properly used)
is more efficient.

You may want to double check your test conditions and instrumentation.

73,
Don W3FPR.

On 3/10/2012 4:38 PM, Vic K2VCO wrote:
> I just did the following experiment: I coupled a grid-dip oscillator to my feed line far
> from the tuners and switching relays. I put it a few inches from the feedline equidistant
> from the conductors. I found that the T network plus DXE balun reduced the signal pickup
> by about 15 dB over the Matchbox!
>
> That means that both radiation and noise pickup on the feedline are much less with the T
> than with the Matchbox. At the same time I verified that there was no detectable
> difference between the strength of received signals coming from the antenna.
>
> This is amazing! It means that the T network and balun is significantly better than the
> Matchbox in this important respect. So much for mythology.
>
> On 3/10/2012 1:11 PM, Vic K2VCO wrote:
>> I've recently been experimenting with tuners. I have a "275 watt" Johnson Matchbox
>> (which is actually good for more than a kW on CW in most cases) and a huge T network
>> that I just built with a massive edge-wound rotary inductor and capacitors with air gaps
>> of about 3/8" (near 10mm). The T network has a DX Engineering "5 kW" rated 1:1 balun on
>> the output.
>>
>> The antenna is an 88-foot dipole fed with 500 ohm open-wire line and some 450-ohm ladder
>> line.
>>
>> I can switch between these tuners instantly. On 40 meter received signals I can detect
>> absolutely no difference in signal strength. The T network is adjusted for the least
>> possible inductance that gives a 1:1 SWR, and the output capacitor is at maximum (300 pf
>> air plus 300 pf ceramic padder)..
>>
>> There is also no difference in noise level. If one of the tuners provided better
>> balance, one would expect that there would be less noise pickup on the feedline. But I
>> don't see this.
>>
>> One anomalous result: there is a weak unstable carrier that I can hear on the Matchbox
>> but not on the T network. I have verified that this is not a birdie, but an actual
>> signal. It could be attributed to feedline pickup -- but wouldn't you expect the
>> matchbox to be better in this regard? I'm investigating further.
>>
>> --
>> Vic, K2VCO
>> Fresno CA
>> http://www.qsl.net/k2vco/
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:Elecraft at mailman.qth.net
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
>
Vic K2VCO
2012-03-11 00:58:18 UTC
Permalink
This is why I checked that real signals received through the antenna were not attenuated
to a detectable degree. I could not tell the difference between the tuners with weak
signals from distant stations.

Reasons that the T network may be as efficient as the Matchbox for this test:

1) In this case the T output capacitor is maximum, which makes it an L network.
2) No switches in the path.
3) Very high-Q inductor in the T network.

On 3/10/2012 4:06 PM, Don Wilhelm wrote:
> Vic,
>
> Be aware that loss in the tuner can reduce the signal pickup - I would not be so quick to
> pass judgement that the Matchbox is less efficient than the T-network tuner - I know the
> link coupled tuner (properly used) is more efficient.
>
> You may want to double check your test conditions and instrumentation.
>
> 73,
> Don W3FPR.
>
> On 3/10/2012 4:38 PM, Vic K2VCO wrote:
>> I just did the following experiment: I coupled a grid-dip oscillator to my feed line far
>> from the tuners and switching relays. I put it a few inches from the feedline equidistant
>> from the conductors. I found that the T network plus DXE balun reduced the signal pickup
>> by about 15 dB over the Matchbox!
>>
>> That means that both radiation and noise pickup on the feedline are much less with the T
>> than with the Matchbox. At the same time I verified that there was no detectable
>> difference between the strength of received signals coming from the antenna.
>>
>> This is amazing! It means that the T network and balun is significantly better than the
>> Matchbox in this important respect. So much for mythology.
>>
>> On 3/10/2012 1:11 PM, Vic K2VCO wrote:
>>> I've recently been experimenting with tuners. I have a "275 watt" Johnson Matchbox
>>> (which is actually good for more than a kW on CW in most cases) and a huge T network
>>> that I just built with a massive edge-wound rotary inductor and capacitors with air gaps
>>> of about 3/8" (near 10mm). The T network has a DX Engineering "5 kW" rated 1:1 balun on
>>> the output.
>>>
>>> The antenna is an 88-foot dipole fed with 500 ohm open-wire line and some 450-ohm ladder
>>> line.
>>>
>>> I can switch between these tuners instantly. On 40 meter received signals I can detect
>>> absolutely no difference in signal strength. The T network is adjusted for the least
>>> possible inductance that gives a 1:1 SWR, and the output capacitor is at maximum (300 pf
>>> air plus 300 pf ceramic padder)..
>>>
>>> There is also no difference in noise level. If one of the tuners provided better
>>> balance, one would expect that there would be less noise pickup on the feedline. But I
>>> don't see this.
>>>
>>> One anomalous result: there is a weak unstable carrier that I can hear on the Matchbox
>>> but not on the T network. I have verified that this is not a birdie, but an actual
>>> signal. It could be attributed to feedline pickup -- but wouldn't you expect the
>>> matchbox to be better in this regard? I'm investigating further.
>>>
>>> --
>>> Vic, K2VCO
>>> Fresno CA
>>> http://www.qsl.net/k2vco/
>> ______________________________________________________________
>> Elecraft mailing list
>> Home: http://mailman.qth.net/mailman/listinfo/elecraft
>> Help: http://mailman.qth.net/mmfaq.htm
>> Post: mailto:Elecraft at mailman.qth.net
>>
>> This list hosted by: http://www.qsl.net
>> Please help support this email list: http://www.qsl.net/donate.html
>>

--
Vic, K2VCO
Fresno CA
http://www.qsl.net/k2vco/
Fred Townsend
2012-03-11 00:56:03 UTC
Permalink
Ron, Rick, Erik: There are many reasons why temperature measurements are a
poor way of evaluating a tuner. There is a method of power measure based on
temperature rise. It's called a bolometer. It only works well if the mass
involved is small. Wiki bolometers if you want the details.

I think there is an even more important reason not to use this approach.
Let's consider the case where the transmitter has a very strong second
harmonic say -10db. If the tuner is doing its job, tuning, not just
matching, the 2nd harmonic will be tuned or filtered out. 10% of the energy
will be lost. What becomes of that energy? In an ideal world that energy
would be reflected into a dummy load, like when you use a circulator. Since
most tuners don't have circulators, part of the energy will be dissipated in
the tuner and part will be reflected back to the transmitter. That energy
that is dissipated in the tuner is a measure of how well, not how poorly,
the tuner is working. BTW in this case measuring SWR at the transmitter will
also suggest the tuner is not doing its job well when it is.

Now we know good rigs don't have strong harmonics but I think I have
illustrated why measuring heat is not a good measure of performance.

73, Fred, AE6QL

-----Original Message-----
From: elecraft-bounces at mailman.qth.net
[mailto:elecraft-bounces at mailman.qth.net] On Behalf Of Erik Basilier
Sent: Saturday, March 10, 2012 12:31 PM
To: 'Ron D'Eau Claire'; 'Rick Stealey'; elecraft at mailman.qth.net
Subject: Re: [Elecraft] high-power tuner

As has been clearly demonstrated in this thread, there are multiple methods
of measurement. The one that gets my vote for elegance is the one with two
tuners back-to-back. With respect to the method that measures temperature
rise, taking into account the mass of the tuner, one also needs to take into
account the specific heat capacity of the tuner. One kilo of material x
doesn't heat up at the same rate as one kilo of material y when the same
heating power is applied. The tuner will of course be a mix of materials, so
one would have to measure the rate at which the tuner heats up when heat is
applied through a know heating source rather than TX power. If it is done
that way, one needs to know neither the mass nor the specific heat capacity,
since what one is measuring is essentially the mass times the specific heat
capacity.

73, Erik K7TV

-----Original Message-----
From: elecraft-bounces at mailman.qth.net
[mailto:elecraft-bounces at mailman.qth.net] On Behalf Of Ron D'Eau Claire
Sent: Saturday, March 10, 2012 11:47 AM
To: 'Rick Stealey'; elecraft at mailman.qth.net
Subject: Re: [Elecraft] high-power tuner

I was investigating tuner losses a few years ago and ran into many of these
same questions.

A physicist buddy pointed out to me that the normal approach to measure loss
in something like a tuner is to put it in a well-insulated chamber and
measure the rise in temperature over time while transmitting. From there on
can calculate the energy required to cause the temperature rise which can be
used to calculate the number of watts of RF that never make it through the
box.

73, Ron AC7AC

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

There seems to have been no answer as to how to accurately measure the loss
in a tuner.
Here is a solution but requires two tuners or at least one calibrated one
that could be used to measure others.
Take first tuner and tune it into the mismatch, say 600 ohms. Use an
antenna analyzer.
Then remove the load, and connect another tuner to the output of the first
(back- to-back - antenna port on first to antenna port on second tuner.)
Then put a 50 ohm load on the second tuner where the transceiver would be
connected, and tune the second tuner to a match. It will have the same
settings as the first tuner, complete symmetry.
Then measure the power in the 50 ohm load to get the loss.

Since both tuners are matching the same load, and the system is symmetrical
the loss contribution by each tuner is half. Repeat for other types of
loads, and now you have a calibrated tuner to use with any tuner you want to
test.

Rick K2XT

______________________________________________________________
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Bob Nielsen
2012-03-11 01:33:48 UTC
Permalink
Bolometers work at pretty low (milliwatt) power levels and you would need to use an attenuator, which could add some error to the measurement. Hewlett Packard made the HP434A Calorimetric Power Meter, which could measure up to 10 watts by matching the temperature in a load with that caused by DC power (which can be accurately measured). I often used one in the early 1960s (this was at work--they were a bit pricey for ham use).

Bob, N7XY

On Mar 10, 2012, at 4:56 PM, Fred Townsend wrote:

> Ron, Rick, Erik: There are many reasons why temperature measurements are a
> poor way of evaluating a tuner. There is a method of power measure based on
> temperature rise. It's called a bolometer. It only works well if the mass
> involved is small. Wiki bolometers if you want the details.
>
> I think there is an even more important reason not to use this approach.
> Let's consider the case where the transmitter has a very strong second
> harmonic say -10db. If the tuner is doing its job, tuning, not just
> matching, the 2nd harmonic will be tuned or filtered out. 10% of the energy
> will be lost. What becomes of that energy? In an ideal world that energy
> would be reflected into a dummy load, like when you use a circulator. Since
> most tuners don't have circulators, part of the energy will be dissipated in
> the tuner and part will be reflected back to the transmitter. That energy
> that is dissipated in the tuner is a measure of how well, not how poorly,
> the tuner is working. BTW in this case measuring SWR at the transmitter will
> also suggest the tuner is not doing its job well when it is.
>
> Now we know good rigs don't have strong harmonics but I think I have
> illustrated why measuring heat is not a good measure of performance.
>
> 73, Fred, AE6QL
>
> -----Original Message-----
> From: elecraft-bounces at mailman.qth.net
> [mailto:elecraft-bounces at mailman.qth.net] On Behalf Of Erik Basilier
> Sent: Saturday, March 10, 2012 12:31 PM
> To: 'Ron D'Eau Claire'; 'Rick Stealey'; elecraft at mailman.qth.net
> Subject: Re: [Elecraft] high-power tuner
>
> As has been clearly demonstrated in this thread, there are multiple methods
> of measurement. The one that gets my vote for elegance is the one with two
> tuners back-to-back. With respect to the method that measures temperature
> rise, taking into account the mass of the tuner, one also needs to take into
> account the specific heat capacity of the tuner. One kilo of material x
> doesn't heat up at the same rate as one kilo of material y when the same
> heating power is applied. The tuner will of course be a mix of materials, so
> one would have to measure the rate at which the tuner heats up when heat is
> applied through a know heating source rather than TX power. If it is done
> that way, one needs to know neither the mass nor the specific heat capacity,
> since what one is measuring is essentially the mass times the specific heat
> capacity.
>
> 73, Erik K7TV
>
> -----Original Message-----
> From: elecraft-bounces at mailman.qth.net
> [mailto:elecraft-bounces at mailman.qth.net] On Behalf Of Ron D'Eau Claire
> Sent: Saturday, March 10, 2012 11:47 AM
> To: 'Rick Stealey'; elecraft at mailman.qth.net
> Subject: Re: [Elecraft] high-power tuner
>
> I was investigating tuner losses a few years ago and ran into many of these
> same questions.
>
> A physicist buddy pointed out to me that the normal approach to measure loss
> in something like a tuner is to put it in a well-insulated chamber and
> measure the rise in temperature over time while transmitting. From there on
> can calculate the energy required to cause the temperature rise which can be
> used to calculate the number of watts of RF that never make it through the
> box.
>
> 73, Ron AC7AC
>
> -----Original Message-----
>
> There seems to have been no answer as to how to accurately measure the loss
> in a tuner.
> Here is a solution but requires two tuners or at least one calibrated one
> that could be used to measure others.
> Take first tuner and tune it into the mismatch, say 600 ohms. Use an
> antenna analyzer.
> Then remove the load, and connect another tuner to the output of the first
> (back- to-back - antenna port on first to antenna port on second tuner.)
> Then put a 50 ohm load on the second tuner where the transceiver would be
> connected, and tune the second tuner to a match. It will have the same
> settings as the first tuner, complete symmetry.
> Then measure the power in the 50 ohm load to get the loss.
>
> Since both tuners are matching the same load, and the system is symmetrical
> the loss contribution by each tuner is half. Repeat for other types of
> loads, and now you have a calibrated tuner to use with any tuner you want to
> test.
>
> Rick K2XT
>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:Elecraft at mailman.qth.net
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:Elecraft at mailman.qth.net
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:Elecraft at mailman.qth.net
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html

_____
N7XY DX Cluster Node - telnet to n7xy.net, port 7300
Erik Basilier
2012-03-11 01:42:44 UTC
Permalink
So, the Calorimetric HP meter uses the same principle as my suggested
measurement, with the only difference being that HP performs the reference
measurement simultaneously with the target measurement rather than
sequentially.

Erik K7TV

>Hewlett Packard made the HP434A Calorimetric Power Meter, which could
measure up to 10 watts by matching the temperature in a >load with that
caused by DC power (which can be accurately measured). I often used one in
the early 1960s (this was at work-->they were a bit pricey for ham use).
>
>Bob, N7XY


.......
> The tuner
> will of course be a mix of materials, so one would have to measure the
> rate at which the tuner heats up when heat is applied through a know
> heating source rather than TX power. If it is done that way, one needs
> to know neither the mass nor the specific heat capacity, since what
> one is measuring is essentially the mass times the specific heat capacity.
>
> 73, Erik K7TV
>
Fred Jensen
2012-03-11 02:16:44 UTC
Permalink
OK folks, I am really truly sorry I started this
tuner-efficiency-by-measuring-its-heat thread. I apologize. It was
sort of an e-nerd joke and I really miscalculated the laugh-factor in
it, it seems there was none, an unfortunate failing for me ... but too
common. Boltzmann's Constant is in my HP48GX calculator, not that I
actually know or care what to do with it at this point in my life.

It would be hugely difficult to get any sort of accuracy in a
measurement of the heat lost in a tuner to find its efficiency, I never
meant it to be real or even close to reality.

Again, I'm sorry to have been joking around on a serious list. Won't do
it again. Please, everyone, use what works, have fun, enjoy the hobby
with the great E-gear. My KPA500 is heating the room far more than my
MFJ989C. If you can make QSO's, it works.

73,

Fred K6DGW
- Northern California Contest Club
- CU in the 2012 Cal QSO Party 6-7 Oct 2012
- www.cqp.org

On 3/10/2012 4:56 PM, Fred Townsend wrote:
> Ron, Rick, Erik: There are many reasons why temperature measurements are a
> poor way of evaluating a tuner. There is a method of power measure based on
> temperature rise. It's called a bolometer. It only works well if the mass
> involved is small. Wiki bolometers if you want the details.
Bill K9YEQ
2012-03-11 02:37:07 UTC
Permalink
Fred,

I would not apologize. I have enjoyed the thread which is about dead anyway.


73,
Bill
K9YEQ


-----Original Message-----
From: elecraft-bounces at mailman.qth.net
[mailto:elecraft-bounces at mailman.qth.net] On Behalf Of Fred Jensen
Sent: Saturday, March 10, 2012 8:17 PM
To: elecraft at mailman.qth.net
Subject: Re: [Elecraft] high-power tuner

OK folks, I am really truly sorry I started this
tuner-efficiency-by-measuring-its-heat thread. I apologize. It was sort of
an e-nerd joke and I really miscalculated the laugh-factor in it, it seems
there was none, an unfortunate failing for me ... but too common.
Boltzmann's Constant is in my HP48GX calculator, not that I actually know or
care what to do with it at this point in my life.

It would be hugely difficult to get any sort of accuracy in a measurement of
the heat lost in a tuner to find its efficiency, I never meant it to be real
or even close to reality.

Again, I'm sorry to have been joking around on a serious list. Won't do it
again. Please, everyone, use what works, have fun, enjoy the hobby with the
great E-gear. My KPA500 is heating the room far more than my MFJ989C. If
you can make QSO's, it works.

73,

Fred K6DGW
- Northern California Contest Club
- CU in the 2012 Cal QSO Party 6-7 Oct 2012
- www.cqp.org

On 3/10/2012 4:56 PM, Fred Townsend wrote:
> Ron, Rick, Erik: There are many reasons why temperature measurements
> are a poor way of evaluating a tuner. There is a method of power
> measure based on temperature rise. It's called a bolometer. It only
> works well if the mass involved is small. Wiki bolometers if you want the
details.


______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Elecraft at mailman.qth.net

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Fred Townsend
2012-03-11 04:50:35 UTC
Permalink
As one Fred to another it was funny in the heat of the battle so to speak.
It fooled me and perhaps the case hardened too. Well done.
73
Fred, AE6QL

-----Original Message-----
From: elecraft-bounces at mailman.qth.net
[mailto:elecraft-bounces at mailman.qth.net] On Behalf Of Fred Jensen
Sent: Saturday, March 10, 2012 6:17 PM
To: elecraft at mailman.qth.net
Subject: Re: [Elecraft] high-power tuner

OK folks, I am really truly sorry I started this
tuner-efficiency-by-measuring-its-heat thread. I apologize. It was sort of
an e-nerd joke and I really miscalculated the laugh-factor in it, it seems
there was none, an unfortunate failing for me ... but too common.
Boltzmann's Constant is in my HP48GX calculator, not that I actually know or
care what to do with it at this point in my life.

It would be hugely difficult to get any sort of accuracy in a measurement of
the heat lost in a tuner to find its efficiency, I never meant it to be real
or even close to reality.

Again, I'm sorry to have been joking around on a serious list. Won't do it
again. Please, everyone, use what works, have fun, enjoy the hobby with the
great E-gear. My KPA500 is heating the room far more than my MFJ989C. If
you can make QSO's, it works.

73,

Fred K6DGW
- Northern California Contest Club
- CU in the 2012 Cal QSO Party 6-7 Oct 2012
- www.cqp.org

On 3/10/2012 4:56 PM, Fred Townsend wrote:
> Ron, Rick, Erik: There are many reasons why temperature measurements
> are a poor way of evaluating a tuner. There is a method of power
> measure based on temperature rise. It's called a bolometer. It only
> works well if the mass involved is small. Wiki bolometers if you want the
details.


______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Elecraft at mailman.qth.net

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Bob K6UJ
2012-03-11 07:02:30 UTC
Permalink
Very interesting discussions about tuners/loss I didn't understand most of what was discussed anyway, hihi.

I have a little tuner history if anyone is interested.
In a letter from Don Wallace W6AM, years ago, he told me he swore by the Johnson Viking Kilowatt tuner. He had one connected between
each of his Collins 75A4 receivers and his rhombics. Not for matching, he had the rhombics dialed in very well, he said the big KW Johnson Matchbox
was a good preselector, said he could peak up a weak signal in the noise enough to get improved copy. He said only the big
Johnson KW tuner with the big coils would work as a preselector, the smaller Johnson Matchbox didn't work as a preselector.
With our radios today I doubt if the big Johnson would help any.


Bob
K6UJ



On Mar 10, 2012, at 8:50 PM, Fred Townsend wrote:

> As one Fred to another it was funny in the heat of the battle so to speak.
> It fooled me and perhaps the case hardened too. Well done.
> 73
> Fred, AE6QL
>
> -----Original Message-----
> From: elecraft-bounces at mailman.qth.net
> [mailto:elecraft-bounces at mailman.qth.net] On Behalf Of Fred Jensen
> Sent: Saturday, March 10, 2012 6:17 PM
> To: elecraft at mailman.qth.net
> Subject: Re: [Elecraft] high-power tuner
>
> OK folks, I am really truly sorry I started this
> tuner-efficiency-by-measuring-its-heat thread. I apologize. It was sort of
> an e-nerd joke and I really miscalculated the laugh-factor in it, it seems
> there was none, an unfortunate failing for me ... but too common.
> Boltzmann's Constant is in my HP48GX calculator, not that I actually know or
> care what to do with it at this point in my life.
>
> It would be hugely difficult to get any sort of accuracy in a measurement of
> the heat lost in a tuner to find its efficiency, I never meant it to be real
> or even close to reality.
>
> Again, I'm sorry to have been joking around on a serious list. Won't do it
> again. Please, everyone, use what works, have fun, enjoy the hobby with the
> great E-gear. My KPA500 is heating the room far more than my MFJ989C. If
> you can make QSO's, it works.
>
> 73,
>
> Fred K6DGW
> - Northern California Contest Club
> - CU in the 2012 Cal QSO Party 6-7 Oct 2012
> - www.cqp.org
>
> On 3/10/2012 4:56 PM, Fred Townsend wrote:
>> Ron, Rick, Erik: There are many reasons why temperature measurements
>> are a poor way of evaluating a tuner. There is a method of power
>> measure based on temperature rise. It's called a bolometer. It only
>> works well if the mass involved is small. Wiki bolometers if you want the
> details.
>
>
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David Gilbert
2012-03-10 20:57:14 UTC
Permalink
I haven't dug it up , but QST April 1995 pp. 30-34 and QST May 1995 pp.
33-37 describes how the QST lab does it.

Dave AB7E



On 3/10/2012 6:17 AM, Rick Stealey wrote:
> There seems to have been no answer as to how to accurately measure the loss in a tuner.
>
Ian Kahn - Ham
2012-03-10 02:20:11 UTC
Permalink
All,

As I said, question shows my lack of knowledge of physics. :-)

Thanks, everyone, for the explanations!

73,

--Ian

Ian Kahn, KM4IK
Roswell, GA
km4ik.ian at gmail.com
K3 #281, P3 #688


On 3/9/2012 6:30 PM, Ian Kahn - Ham wrote:
> This probably shows my gross lack of knowledge of the physics involved
> here, but what does the weight of the tuner have to do with its
> efficiency?
>
> 73,
>
> --Ian
>
> Ian Kahn, KM4IK
> Roswell, GA
> km4ik.ian at gmail.com
> K3 #281, P3 #688
>
>
> On 3/9/2012 6:14 PM, Fred Jensen wrote:
>> On 3/9/2012 2:24 PM, WILLIS COOKE wrote:
>>
>>> If you need a tuner, your
>>> antenna does not meet this criteria so, what are you using to form
>>> your opinion?
>> Weigh the tuner, then transmit continuously, measure the temperature
>> rise, and when it's stable, calculate the heat loss [something to do
>> with Boltzman's Constant -- the tuner *is* painted black]. What doesn't
>> leave as heat must leave as RF. Did it years ago on a 10 KW FM
>> broadcast transmitter [4 ea 4-1000's], and it came within one percent of
>> the efficiency measured with the water-cooled dummy load. YMMV however.
>>
>> 73,
>>
>> Fred K6DGW
>> - Northern California Contest Club
>> - CU in the 2012 Cal QSO Party 6-7 Oct 2012
>> - www.cqp.org
>>
>> ______________________________________________________________
>> Elecraft mailing list
>> Home: http://mailman.qth.net/mailman/listinfo/elecraft
>> Help: http://mailman.qth.net/mmfaq.htm
>> Post: mailto:Elecraft at mailman.qth.net
>>
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>> Please help support this email list: http://www.qsl.net/donate.html
Bob K6UJ
2012-03-10 00:56:28 UTC
Permalink
QST had an article a while back comparing tuners, MFJ, Palomar, Drake and several others if I remember correctly.
They had a chart showing the loss per band per each tuner.
They included the old Johnson Viking matchbox in their ranking too. The old Johnson was right up there
in the top rankings, with very low loss. I wish I still had my old Johnson, sigh...............
Anyway a search on the ARRL webpage for QST articles about tuners should show the article.

Bob
K6UJ



On Mar 9, 2012, at 2:10 PM, W5RDW wrote:

> Never had any reason to wonder if my MFJ-998 has more than normal loss. It
> hasn't let any smoke out of the cabinet yet! I use to run a Drake L-7 thru
> it, but now use the KPA500 all the time and have retired the Drake.
>
>> /Most of the MFJ tuners tend to rank pretty low in that respect./
>
> Dave, I'd be interested in reading about the info you have on the MFJ tuner
> loss.
>
> -----
> Roger W5RDW
> --
> View this message in context: http://elecraft.365791.n2.nabble.com/high-power-tuner-tp7314904p7359740.html
> Sent from the Elecraft mailing list archive at Nabble.com.
> ______________________________________________________________
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> Please help support this email list: http://www.qsl.net/donate.html
Don Wilhelm
2012-03-10 02:30:49 UTC
Permalink
Bob,

One can construct a link coupled tuner that will have even greater
efficiency than the venerable Johnson Matchbox. It will have plug-in
coils, and the antenna will connect to taps on the coil rather than
using a differential capacitor - that tuner will have a greater matching
range than the Matchbox as well as having less loss. The drawback is
that it does not lend itself well to bandswitching. OTOH, it does not
need to be in an enclosure, can be built on a piece of wood (yes, mine
is built on a wooden board), so the plug-in coil is easily accessed and
changed to whatever band one wants ot operate on. Once the settings for
any one antenna have been established and recorded, changing bands takes
less than 30 seconds.

As L.B.Cebik has stated many times, link coupled balanced tuners are the
most efficient. Their loss is close to zero.

73,
Don W3FPR

On 3/9/2012 7:56 PM, Bob K6UJ wrote:
> QST had an article a while back comparing tuners, MFJ, Palomar, Drake and several others if I remember correctly.
> They had a chart showing the loss per band per each tuner.
> They included the old Johnson Viking matchbox in their ranking too. The old Johnson was right up there
> in the top rankings, with very low loss. I wish I still had my old Johnson, sigh...............
> Anyway a search on the ARRL webpage for QST articles about tuners should show the article.
>
> Bob
> K6UJ
>
>
>
> On Mar 9, 2012, at 2:10 PM, W5RDW wrote:
>
>> Never had any reason to wonder if my MFJ-998 has more than normal loss. It
>> hasn't let any smoke out of the cabinet yet! I use to run a Drake L-7 thru
>> it, but now use the KPA500 all the time and have retired the Drake.
>>
>>> /Most of the MFJ tuners tend to rank pretty low in that respect./
>> Dave, I'd be interested in reading about the info you have on the MFJ tuner
>> loss.
>>
>> -----
>> Roger W5RDW
>> --
>> View this message in context: http://elecraft.365791.n2.nabble.com/high-power-tuner-tp7314904p7359740.html
>> Sent from the Elecraft mailing list archive at Nabble.com.
>> ______________________________________________________________
>> Elecraft mailing list
>> Home: http://mailman.qth.net/mailman/listinfo/elecraft
>> Help: http://mailman.qth.net/mmfaq.htm
>> Post: mailto:Elecraft at mailman.qth.net
>>
>> This list hosted by: http://www.qsl.net
>> Please help support this email list: http://www.qsl.net/donate.html
> ______________________________________________________________
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>
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> Please help support this email list: http://www.qsl.net/donate.html
>
Fred Jensen
2012-03-10 01:00:36 UTC
Permalink
"The only thing that shows gross lack of knowledge is not asking the
question for which you need the answer." [Cal Poly Physics Professor
whose name escapes me but whose class I remember as a personal struggle].

To know the net rate of heat input [i.e. generation within the tuner]
from the temperature change, you need to know the mass of the tuner.
Weigh it and a little arithmetic and you have the mass. The RF that
doesn't heat the tuner must go up the coax. Weighing has nothing to do
with the efficiency itself, it is part of the
not-exactly-precise-measurement-method I suggested but don't recommend.

For the FM transmitter, we had temperature sensors in the grid
compartment on the bottom where the refrigerated air entered, and just
far enough above the chimneys where it came out hot. There was a water
manometer to measure the pressure difference between the air inlet and
the vent that took the hot air outside. The pressure differential was
very low so I assumed that the air got hot at a constant pressure. This
was an important assumption because at that time I didn't know enough
calculus for the alternative. I probably don't remember now either.

I got up very early one morning [was 17 and living at the TX], and
turned on the filaments. When the temperatures had stabilized, and
knowing the filaments were turning 600W of electricity into almost 600W
of heat, I could calculate the mass rate of the air flowing through the
chimneys. Sign on came, I let the temps stabilize at 5.3 KV and 3.5A
plate current, and calculated the heat input to give those temps. That
power blew out the vent, the rest went up the 3 1/8" rigid coax to the
antenna, I assumed. Turned out we were a little overpower, almost 12KW
for about 70% efficiency and the 4-1000 plates were fairly bright. OK,
really bright.

For the case of the tuner, it's not so simple and I skillfully tried to
skate past the effect of radiation from the "black body" [i.e. the
"black" tuner which, while black, probably isn't a real black body] as
the RF heats it. While I know the first six digits of Boltzmann's
Constant [138065 -- it used to be the master unlock password for a UHF
repeater I maintain], I've forgotten some of the physics and math I used
to know and it's guaranteed that, were I to attempt that calculation on
this list, a countable infinity of people would correct me and then each
other ... likely forever or until Eric stepped in.

It was a e-nerd semi-joke, which I've found are not often funny except
to other e-nerds. Undaunted however, I continued. Cookie's comment
about measuring the efficiency of tuners being hard is very true, and
you can't do it with a Micronta SWR meter from Radio Shack. It will
involve some math, maybe even calculus, and quite a bit of expensive
test equipment.

I would trust ARRL's numbers, and those of a few others like Sherwood,
I'll remain a little skeptical of the Mfr's numbers, if they even
publish them.

73,

Fred K6DGW
- Northern California Contest Club
- CU in the 2012 Cal QSO Party 6-7 Oct 2012
- www.cqp.org

On 3/9/2012 3:30 PM, Ian Kahn - Ham wrote:
> This probably shows my gross lack of knowledge of the physics involved
> here, but what does the weight of the tuner have to do with its
efficiency?
Tim
2012-03-10 16:53:15 UTC
Permalink
Hi All,

What you really need to do is to put the whole tuner inside a calorimeter
and measure the rate of temperature change to determine the the dissipated
wattage.

Tim
gm4lmh
Phil &amp; Debbie Salas
2012-03-10 01:42:22 UTC
Permalink
I've been making tuner loss measurements for an upcoming QST review of some
remote autotuners. My set-up is similar to the ARRL lab, but I've made a
few changes. I have two different load boxes. One is a resistive load box
that lets me measure loss with loads from 12-800 ohms. The second load box
simulates different types of electrically short end-fed antennas - like a 43
footer on lower frequency bands, or an 8-footer like you might have mobile,
and other combinations. I use Caddock thick-film 30-watt resistors for the
resistive portion of both test boxes. For the short antenna simulator, I
use series silver mica capacitors with shunt Caddock resistors.

Basically, I feed the 40 watt output of my test transceiver through a high
power 6dB pad, through an Array Solutions PowerMaster, then to the tuner.
So my test power is 10 watts. The 6dB pad helps keep the power relatively
constant, but primarily ensures that any reflected power from a non-perfect
tune (the tuners have a target of 1.5:1) is attenuated 12dB more if
re-reflected by the transmitter. The output of the tuner feeds the load
box. The load box has an output that feeds a 50 ohm attenuator/Minicircuits
PWR-6GHS+ power sensor (that output is shunted or seriesed with Caddock
resistors to give the required test impedance). So I start with no tuner
in-line and adjust the Minicircuits offset so it and the PowerMaster read
the same at 10 watts. They are both NIST-traceable cal'd, and were within
3% of each other, but I adjusted the offset so they are within 1%. Then I
insert the autotuner, hit it with RF and let it tune. When tuning is
complete I adjust the input drive so it is exactly 10 watts, read the output
on the PWR-6GHS+, and compare that to the expected power under lossless
conditions.

Phil - AD5X
Don Wilhelm
2012-03-10 02:46:14 UTC
Permalink
Phil,

My lab "simulated antenna" consists of a dummy load and a Johnson Matchbox.
I can connect a dummy load to the Matchbox and twist the dials to create
just about any reasonable impedance that you want. I set it up using my
MFJ259B if I am looking for something specific.

The helpful parameter is that it is frequency sensitive (just like an
antenna), while a resistive dummy load is not sensitive to frequency.

I do normally use Caddock Thick Film resistors to create dummy loads. I
have several 50 ohm loads, but also have a 25 ohm (2 50 ohm resistors in
parallel) and a 100 ohm (2 50 ohm resistors in series) that I use for
setting the 2:1 SWR point while I am calibrating wattmeters. These are
1% tolerance loads, and if mounted to the connector (and heat sink) with
short leads present a flat response up to 500 MHz.

Note well that the Caddock literature says only that the 50 ohm
resistors are non-reactive - that may be true for other values, but I
have taken that information at face value and use only the 50 om
resistors for dummy loads.

73,
Don W3FPR

On 3/9/2012 8:42 PM, Phil & Debbie Salas wrote:
> I've been making tuner loss measurements for an upcoming QST review of some
> remote autotuners. My set-up is similar to the ARRL lab, but I've made a
> few changes. I have two different load boxes. One is a resistive load box
> that lets me measure loss with loads from 12-800 ohms. The second load box
> simulates different types of electrically short end-fed antennas - like a 43
> footer on lower frequency bands, or an 8-footer like you might have mobile,
> and other combinations. I use Caddock thick-film 30-watt resistors for the
> resistive portion of both test boxes. For the short antenna simulator, I
> use series silver mica capacitors with shunt Caddock resistors.
>
> Basically, I feed the 40 watt output of my test transceiver through a high
> power 6dB pad, through an Array Solutions PowerMaster, then to the tuner.
> So my test power is 10 watts. The 6dB pad helps keep the power relatively
> constant, but primarily ensures that any reflected power from a non-perfect
> tune (the tuners have a target of 1.5:1) is attenuated 12dB more if
> re-reflected by the transmitter. The output of the tuner feeds the load
> box. The load box has an output that feeds a 50 ohm attenuator/Minicircuits
> PWR-6GHS+ power sensor (that output is shunted or seriesed with Caddock
> resistors to give the required test impedance). So I start with no tuner
> in-line and adjust the Minicircuits offset so it and the PowerMaster read
> the same at 10 watts. They are both NIST-traceable cal'd, and were within
> 3% of each other, but I adjusted the offset so they are within 1%. Then I
> insert the autotuner, hit it with RF and let it tune. When tuning is
> complete I adjust the input drive so it is exactly 10 watts, read the output
> on the PWR-6GHS+, and compare that to the expected power under lossless
> conditions.
>
> Phil - AD5X
>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:Elecraft at mailman.qth.net
>
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> Please help support this email list: http://www.qsl.net/donate.html
>
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