Topband: T-200 vs. T-300

[Martin]

For those who intend to build the FCP INV. L. with a T-200-2 (or an
antenna tuner).
Me and a few guys from our club wound different types of baluns and
chokes on different material and measured them with a
analyser. We found the T-200-2 next to useless below 3 Mhz due to a low
AL value (uH/100 turns). The T-200A-2 is a lot better, but still not
really good in balancing. You better use ferrites (FT-something) as long
as you use moderate power.

BUT if you go QRO, you should stick with the iron powder cores.

I once replaced the T-200-2 in my homebrew s-match with a ferrite. I
changed back the same day, cuz after a few seconds with 750W the ferrite
got so hot you would not want to touch it. The T-200-2 runs cool over an
entire contest. Next step is to replace it with a T-300A-2.

Below you find a list of cores with their corresponding Al Value.
You can clearly see that the T-300-2 is even lower than the T-200-2.
For the FCP INV L. i think a T-300A-2 or even better a T-400A-2 is best
choice, may it be expensive.

Core Al Value
T-200-2 120
T-200A-2 218
T-225-2 120
T-225A-2 215
T-300-2 114
T-300A-2 228
T-400-2 180
T-400A-2 360

I'm not a technician or rf-specialist and english is not my native
language, so please forgive me if my explanations are a bit ragged.
Yes, i use a T-200-2 in a tuner, which of course is not the same as an
antenna, but my feeling tells me i'm on the right track when i say that
a T-200-2 is no good choice for frequencies below 3Mhz,


http://toroids.info
http://www.qrz.lt/ly1gp/amidon.html

[Mikael Larsmark]

OK, but there is a huge amount of different materials in ferrites too.
Which kind of material did you use? I've used -61 material in a lot of
high power applications without any problems of them overheating. You
barely feel any temperature raise in them at all if for example using
them as a UN-UN transformer. I like the FT240-61 core very much, it can
handle a lot of power.

Mike, SM2WMV (SJ2W)
http://www.sj2w.se/contest/

Post by Martin
For those who intend to build the FCP INV. L. with a T-200-2 (or an
antenna tuner).
Me and a few guys from our club wound different types of baluns and
chokes on different material and measured them with a
analyser. We found the T-200-2 next to useless below 3 Mhz due to a low
AL value (uH/100 turns). The T-200A-2 is a lot better, but still not
really good in balancing. You better use ferrites (FT-something) as long
as you use moderate power.
BUT if you go QRO, you should stick with the iron powder cores.
I once replaced the T-200-2 in my homebrew s-match with a ferrite. I
changed back the same day, cuz after a few seconds with 750W the ferrite
got so hot you would not want to touch it. The T-200-2 runs cool over an
entire contest. Next step is to replace it with a T-300A-2.
Below you find a list of cores with their corresponding Al Value.
You can clearly see that the T-300-2 is even lower than the T-200-2.
For the FCP INV L. i think a T-300A-2 or even better a T-400A-2 is best
choice, may it be expensive.
Core Al Value
T-200-2 120
T-200A-2 218
T-225-2 120
T-225A-2 215
T-300-2 114
T-300A-2 228
T-400-2 180
T-400A-2 360
I'm not a technician or rf-specialist and english is not my native
language, so please forgive me if my explanations are a bit ragged.
Yes, i use a T-200-2 in a tuner, which of course is not the same as an
antenna, but my feeling tells me i'm on the right track when i say that
a T-200-2 is no good choice for frequencies below 3Mhz,
http://toroids.info
http://www.qrz.lt/ly1gp/amidon.html

[Tod - ID]

A couple rules for toroidal inductors might be useful. To increase the reactance you increase the number of turns -- the inductance goes up approximately the square of the number of turns. To increase the power handling capability you add additional cores to make a stack of cores. This will also help with the inductance since the toroid core AL value is affected by the cross sectional area of the core.

I would expect that stacking cores might be the more economic route to the desired result.

If you are simply building a an RF choke to prevent feed line common mode RF current you should be using Type 31 material. For really good RF choking at 1.8 MHz you should plan on about six turns through at least five stacked cores of type 31 ferrite 2.4 inches
o.d. [60 mm] Such a choke will have about 5000 ohms of impedance, mostly resistive. It will certainly handle 1.5 KW going through the feed line [ if the feed line can handle the power]. See K9CY's online paper discussing such RF chokes. You may also want to check my web site for some measurements of various RF chokes made with type 31 using different numbers of cores and turns.

Tod, K0TO


Sent from my iPad 2

[Paul Christensen]

"A couple rules for toroidal inductors might be useful. To increase the
reactance you increase the number of turns -- the inductance goes up
approximately the square of the number of turns. To increase the power
handling capability you add additional cores to make a stack of cores.
This will also help with the inductance since the toroid core AL value is
affected by the cross sectional area of the core."

Another important rule when winding CM chokes: On common-mode currents (the
bad current), an inductance equal to 2*L is added in series with each of the
two conductors. On differential mode currents (the good current), L cancels
and has no effect. Ever wonder why we can keep adding so much L in CM choke
windings and it does not appreciably degrade differential-mode current and
frequency response?

Paul, W9AC

[Tod - Idaho]

You are correct Carl, I should have inserted the URL's. My excuse, and it is
pretty flimsy, is that I was drafting the reply on my iPad2 which is a bit
harder to go off and get links on than my laptop [now being used].

The link to my web site is: http://www.k0to.us/HAM/ham.htm
The articles are "How to estimate RF Choke impedance" and "July 24 - RF
Choke measurements"


K9YC's article is: A Ham's Guide to RFI, Ferrites, Baluns, and Audio
Interfacing .... The Cookbook pages are 35 and 36. There is substantial
other material worth checking on, but those two pages give information that
can be used to go off and buy parts and build.
The URL for his article is: www.audiosystemsgroup.com/RFI-Ham.pdf

Tod, K0TO


-----Original Message-----
From: ZR [mailto:zr at jeremy.mv.com]
Sent: Thursday, December 15, 2011 9:04 AM
To: Tod - ID; Martin
Cc: topband at contesting.com
Subject: Re: Topband: T-200 vs. T-300

Some links to that info might help.

Carl
KM1H

[Rick Karlquist]

Post by Martin
BUT if you go QRO, you should stick with the iron powder cores.
I once replaced the T-200-2 in my homebrew s-match with a ferrite. I
changed back the same day, cuz after a few seconds with 750W the ferrite
got so hot you would not want to touch it. The T-200-2 runs cool over an
entire contest. Next step is to replace it with a T-300A-2.

I don't agree with this generalization. I have built many legal
limit transformers and baluns with ferrite, and have not had
overheating problems. Of course it is necessary to use the correct
type of ferrite for the application and the right number of turns on
it, etc. It is hard to comment specifically on your anecdotal data
on your ferrite failure without additional details. The main
misunderstanding I have encountered is that users sometimes choose
a ferrite with a very high permeability, but which has a high
loss tangent at the frequency of interest. It is often better to
use a lower permeability material with a low loss tangent. Although
the shunt impedance may not be as high in the latter case, the
parallel resistance (Rp) will be much higher and hence the loss
will be much lower.

Powered iron cores have a very limited permeability range, well below
100. They are cheaper than ferrite cores and can be made to work
by using a sufficient number of turns. They are mainly useful for
making inductors rather than transformers, because the Al value is
more closely specified than ferrite. Also, you want a low Al value
when making an inductor because you get improved inductance resolution
(since the number of turns must be an integer).

Rick N6RK

[Guy Olinger K2AV]

For those building an isolation transformer for a 160M 5/16 FCP -- PLEASE
READ! IMPORTANT!

Martin has the right instincts, says it feels fishy for this. But it's
worse than he thinks. And don't even consider using ferrites.

The T300A-2 core and 20 bifilar turns were SPECIFICALLY chosen to produce a
residual inductance value in the right order of magnitude to cancel a
typical residual capacitive reactance from a 160 meter 5/16 wave single
wire folded counterpoise, AND provide enough coupling to make the
transformer work, AND maintain a low enough loss to operate QRO without
heating, or especially to operate QRP without further handicapping the
operator with needless loss. This allows the builder of the "simple
solution" to prune the wire to get resonance and remain somewhere around an
ELECTRICAL quarter wave radiator. So this works for T's, L's, U's,
straight verticals, 1/8 wave-ish raised radials and HOA miscellaneous
stealth wires.

A T300 form factor is the minimum to wind 20 bifilar turns on the INSIDE
diameter. Twenty turns (forty wires) fills up the inside diameter. Less
than the T300A-2's 22.8 A sub L number (Amidon does not use the decimal
point) and residual inductance is reduced and doesn't match the FCP. Use
of a mu of 20 (#1 material) to pull this off on a smaller form factor with
fewer turns adds loss, and gets into heating.

FERRITES?? DO NOT use ferrites. This is a transformer, NOT a balun. There
is a voltage differential across the winding. The winding will go lossy.
We wind up overheating ferrites and cracking. This is not a balun with
guaranteed 100% cancelling counter-currents. Powdered iron is required.

The Amidon T300A-2 can be replaced with a stacked PAIR of Amidon T300-2,
with a SINGLE Micrometals T300-2D, or a stacked PAIR of Micrometals T300-2.
You can find the Micrometals cores on eBay. You CAN use the Amidon
T400A-2, but that core is forty bux compared to the T300A-2's sixteen, and
I haven't figured the correct smaller number of turns to balance the FCP,
and since the T300A-2 does the job, why bother to blow 24 bux? Maybe for
5kW RF someone needs to do the work.

My specification for results and success of design is predicated on the
particular design of isolation transformer. Move away from that and YOU
ARE ON YOUR OWN. Further, do not be deceived, to use the 5/16 wave FCP, an
isolation transformer is REQUIRED. We ALREADY TRIED using regular balun
designs to keep the counterpoise current off the feedline to an FCP. They
do not work in this app. Been there, done that. With the wrong kind of
dirt under the antenna, using a regular balun goes dummy load on you,
merely lossy otherwise. Don't try to feed this with a regular balun and
then come back and complain that it didn't work. OF COURSE it didn't work.
WE DISCOVERED it wouldn't work. WE TOLD YOU it wouldn't work.

Those of you carefully thinking this through could say that you could use a
series reactor AND a regular balun. Yeah, yeah, BUT this is now a straight
inductor on a core WITHOUT any counter-current to cut down on the losses.
So you lose big time on two counts: First, you only saved the cost of 7.5
feet of teflon on wire vs the isolation transformer, because you STILL had
to do core+single winding PLUS it also cost you the balun. Second, you
lost the fairly high percentage of counter-current cancellation using the
bifilar winding in the isolation transformer. So your coil plus regular
balun costs you more loss for QRP and heat for QRO.

If your beef is that it's too hard to make and get the right materials,
Balun Designs is making a model 1142s, which you can buy ready-made, now,
and does my full specification without any corner cutting. (I have no
financial interest in Balun Designs)
http://www.balundesigns.com/servlet/the-108/1-cln-1-High-Isolation-Balun/Detail


This is 160 meters, guys. You can't use the miniature stuff down here
without going lossy. You're talking about less money than taking the
family to a restaurant. Why bother with cheep cheep.

73, Guy K2AV (the inventor)

Post by Martin
For those who intend to build the FCP INV. L. with a T-200-2 (or an
antenna tuner).
Me and a few guys from our club wound different types of baluns and
chokes on different material and measured them with a
analyser. We found the T-200-2 next to useless below 3 Mhz due to a low
AL value (uH/100 turns). The T-200A-2 is a lot better, but still not
really good in balancing. You better use ferrites (FT-something) as long
as you use moderate power.
BUT if you go QRO, you should stick with the iron powder cores.
I once replaced the T-200-2 in my homebrew s-match with a ferrite. I
changed back the same day, cuz after a few seconds with 750W the ferrite
got so hot you would not want to touch it. The T-200-2 runs cool over an
entire contest. Next step is to replace it with a T-300A-2.
Below you find a list of cores with their corresponding Al Value.
You can clearly see that the T-300-2 is even lower than the T-200-2.
For the FCP INV L. i think a T-300A-2 or even better a T-400A-2 is best
choice, may it be expensive.
Core Al Value
T-200-2 120
T-200A-2 218
T-225-2 120
T-225A-2 215
T-300-2 114
T-300A-2 228
T-400-2 180
T-400A-2 360
I'm not a technician or rf-specialist and english is not my native
language, so please forgive me if my explanations are a bit ragged.
Yes, i use a T-200-2 in a tuner, which of course is not the same as an
antenna, but my feeling tells me i'm on the right track when i say that
a T-200-2 is no good choice for frequencies below 3Mhz,
http://toroids.info
http://www.qrz.lt/ly1gp/amidon.html
--
73, Martin DM4iM
_______________________________________________
UR RST IS ... ... ..9 QSB QSB - hw? BK

[Rick Karlquist]

Post by Guy Olinger K2AV
Martin has the right instincts, says it feels fishy for this. But it's
worse than he thinks. And don't even consider using ferrites.
The T300A-2 core and 20 bifilar turns were SPECIFICALLY chosen to produce a
residual inductance value in the right order of magnitude to cancel a
typical residual capacitive reactance from a 160 meter 5/16 wave single
wire folded counterpoise, AND provide enough coupling to make the
transformer work, AND maintain a low enough loss to operate QRO without
heating, or especially to operate QRP without further handicapping the
operator with needless loss. This allows the builder of the "simple
solution" to prune the wire to get resonance and remain somewhere around

I'm trying to understand here what is magic about powdered iron.

It is true you can't just use any random piece of ferrite.
But if the T300A-2 were replaced with LOW PERMEABILITY ferrite
having the same permeability as a T300A-2 core, it would produce
the required residual inductance. The loss of low permeability
ferrite is extremely low, probably lower than powdered iron.
Coupling is a function of how the turns are wound, not the core material.

Am I missing something?

Rick N6RK

[Guy Olinger K2AV]

Hi Rick,

No magic. Just the right stuff, for the FCP, anyway.

To your particulars, when Jerry Sevick measured various ferrites, he
measured the lowest loss at mu=40. This was very low, as was the #2
powdered iron at mu=10, the lowest of the powdered iron formulas. So use
of ferrites introduces a significantly reduced number of turns, with a much
more coarse granularity of possible inductive values, that has to be worked
out to use with the FCP, AND the behavior of the mu=40 core under highly
reactive loads is not spec'd by the manufacturer. The ferrite will have far
less radiating surface if it does heat up under extreme reactive load, AND
the length of the parallel bifilar wires may not be enough to cover 160
with the needed behavior in this app.

But my admonition about no ferrites has more to do with my knowing that
people have misc T240 and T200 form factor ferrites of ALL KINDS laying
around, and want to use the one they just found down in the junk box, which
does NOT have the material # or mu marked on it anywhere. And these
requests seem to pop up just before a contest, when most hope of getting
the correct stuff before contest has gone by the wayside. You will note
that I have pounded in Amidon T300A-2 #2 powdered iron toroid or strict
equivalent, over and over again. And I get back "please, please, please
tell me that I can use my junkbox ferrite toroid". But don't hold your
breath. In over four years of working with non-resonant antenna solutions
on 160, **NONE** of the ferrites we tried to use made it. We burnt or
cracked ALL of them at QRO. ALL of them. Really. Ferrite demolition
derby.

I have a new collection of #31 ferrite stuff, but I use those in low band
RFI suppression, not transformers. So I'm NOT going to tell anyone it's OK
to use a ferrite toroid for feeding an FCP.

Beyond that, what is NOT in doubt is that the #2 powdered iron choice works
and works well. The installations where I have been able to run QRO brick
on key and quick go check toroid temp have all been stone cold. Anyone has
contrary experience please let us know ASAP. We will certainly want to
investigate and determine why in one place and why not in another.

As to why he made his #2 powdered iron choice, Jerry Sevick W2FMI, covers
this convincingly in his book, pages 58-63, which I will NOT try to
reproduce on the reflector, as even if I did, I can't pass along the
essential graphs, photos and diagrams. ("Understanding, Building, and
Using Baluns and Ununs -- Theory and Practical Designs for the
Experimenter", Jerry Sevick W2FMI, Copyright 2003, CQ Communications, Inc.,
Hicksville, New York)

I have found, over the time that I have been working on top-band issues,
that dropping back after blowing something up and consulting W2FMI or his
material has been most valuable.

Alas, Jerry is a silent key, and I can no longer phone him to further
expound upon his choices. He particularly chose the large #2 powdered iron
cores for applications with a lot of stress on the core, particularly 160
meters. Some key quotes:

"Because my simple loss measurements indicated that the higher permeability
powdered-irons had more loss than the No. 2 material, I decided to design a
4:1 Ruthroff Balun using this material--but with a larger core and more
turns than the McCoy Balun. Although McCoy's design has enjoyed
considerable success over the years, I felt that a larger inductive
reactance was desirable in order to assure better performance on the lower
frequency bands (particularly 160 meters). [Ibid p.59]

"I knew ... that loss with ferrite materials was related to the voltage
drop along the length of the [bifilar winding] and to the ... permeability.
Permeabilities of 40 (No. 67 Ferrite) exhibited the lowest loss. ...
powdered iron #2 material with a permeability of 10 also showed the very
same low loss. Because powdered-iron material has been known to be more
rugged and linear than ferrite material, this suggested that other
powdered-irons ... should be investigated. ... However all four materials
showed a definite lower input impedance than #2 material, ..." [Ibid p.59]

Sevick had access to all of the ferrites, but did not choose any of them
for his monster hang-on-the-back-of-the-tuner 4:1 Balun, especially
intended to deal with wild voltages, very reactive loads, etc, and handle
them as well on 160 as 80-10. Instead Sevick chose the T400A-2 and #2
powdered iron to lay out there as his personal method. So we've done the
same. And everywhere we've used teflon-sleeved #14 double polyimide on the
#2 powdered iron cores, bad stuff has just quit happening, they work, and
they run stone cold.

At various scattered places in the book Sevick talks about all the issues
that come to bear on designing an isolation transformer on 160 meters. I
may not be able to develop a federal level proof case satisfactory so some,
but I am sticking with Mr. Sevick. His guidance has always panned out and
explained what was ailing. He did his high-stress 160 meter windings on
large #2 powdered iron toroids after research. So are we. We have the
hard-won results that prove out Sevick's and our choices.

73, Guy.

Post by Rick Karlquist

Post by Guy Olinger K2AV
Martin has the right instincts, says it feels fishy for this. But it's
worse than he thinks. And don't even consider using ferrites.
The T300A-2 core and 20 bifilar turns were SPECIFICALLY chosen to produce a
residual inductance value in the right order of magnitude to cancel a
typical residual capacitive reactance from a 160 meter 5/16 wave single
wire folded counterpoise, AND provide enough coupling to make the
transformer work, AND maintain a low enough loss to operate QRO without
heating, or especially to operate QRP without further handicapping the
operator with needless loss. This allows the builder of the "simple
solution" to prune the wire to get resonance and remain somewhere around

I'm trying to understand here what is magic about powdered iron.
It is true you can't just use any random piece of ferrite.
But if the T300A-2 were replaced with LOW PERMEABILITY ferrite
having the same permeability as a T300A-2 core, it would produce
the required residual inductance. The loss of low permeability
ferrite is extremely low, probably lower than powdered iron.
Coupling is a function of how the turns are wound, not the core material.
Am I missing something?
Rick N6RK

[Guy Olinger K2AV]

#2 powdered iron at mu of 10 is the lowest mu of the powdered iron types
listed with a frequency range that covers 160 meters (in some lists #2 is
2-30). You can rest assured Jerry Sevick had the list below. In his 160
meter comparison with #2 material, he tested 1,3,15 and 26. Number 6 really
doesn't work under 10 MHz, as specified in other lists. It's a "replaced"
mix that has had problems. Here's a composite list of powdered iron
materials from various incomplete sources.

0 Mix (Tan) 100-300 MHz u=1
1 Mix (Blue) 0.5-5 Mhz u=20
*2 Mix* (Red) 1-30 MHz, high volume resist. u=10 [Alt list 2-30 Mhz]
3 Mix (Gray) .05-.5 MHz, u=35
*6 Mix* (Yellow) 1-50 MHz, similar to mix #2. u=8 [alt list 10-50 MHz, alt
list use #8]
7 Mix 3-35 MHz, u=9 small cores only
*8 Mix *(Yellow / Red) 1-50 MHz, replaces 6 mix. u=35
10 Mix 30-100 MHz, u=6
12 Mix 50-200 MHz, u=4
15 Mix 0.1-2 MHz, u=25
*17 Mix* (Blue/Yellow) 50-200 MHz, good Q. u=3 [alt list u=4]
*18 Mix* (Green/Red) u=55, Low Core Loss, Similar to 8 Mix
*26 Mix* (Yellow/White) DC-800 KHz, great 60 Hz.
EMI range. Line 'em up on speakers / AC wires u=75
*40 Mix* (Green/Yellow) Power conversion similar to mix 26
*52 Mix* (Green/Blue) DC-1 MHz, high perm. u=75

73, Guy.

----- Original Message ----- From: "Guy Olinger K2AV" <
olinger at bellsouth.net>
To: <richard at karlquist.com>
Cc: <topband at contesting.com>; "Martin" <hamradio at vr-web.de>
Sent: Thursday, December 15, 2011 10:05 PM
Subject: Re: Topband: T-200 vs. T-300
Hi Rick,

Post by Guy Olinger K2AV
No magic. Just the right stuff, for the FCP, anyway.
To your particulars, when Jerry Sevick measured various ferrites, he
measured the lowest loss at mu=40. This was very low, as was the #2
powdered iron at mu=10, the lowest of the powdered iron formulas.

Since when is a 2 mix the lowest mu? It is ideal for QRO and HF since 6
and 7 mix arent made in QRO sizes and arent suitable at 160 anyway.
Carl
KM1H
So use

Post by Guy Olinger K2AV
of ferrites introduces a significantly reduced number of turns, with a much
more coarse granularity of possible inductive values, that has to be worked
out to use with the FCP, AND the behavior of the mu=40 core under highly
reactive loads is not spec'd by the manufacturer. The ferrite will have far
less radiating surface if it does heat up under extreme reactive load, AND
the length of the parallel bifilar wires may not be enough to cover 160
with the needed behavior in this app.
But my admonition about no ferrites has more to do with my knowing that
people have misc T240 and T200 form factor ferrites of ALL KINDS laying
around, and want to use the one they just found down in the junk box, which
does NOT have the material # or mu marked on it anywhere. And these
requests seem to pop up just before a contest, when most hope of getting
the correct stuff before contest has gone by the wayside. You will note
that I have pounded in Amidon T300A-2 #2 powdered iron toroid or strict
equivalent, over and over again. And I get back "please, please, please
tell me that I can use my junkbox ferrite toroid". But don't hold your
breath. In over four years of working with non-resonant antenna solutions
on 160, **NONE** of the ferrites we tried to use made it. We burnt or
cracked ALL of them at QRO. ALL of them. Really. Ferrite demolition
derby.
I have a new collection of #31 ferrite stuff, but I use those in low band
RFI suppression, not transformers. So I'm NOT going to tell anyone it's OK
to use a ferrite toroid for feeding an FCP.
Beyond that, what is NOT in doubt is that the #2 powdered iron choice works
and works well. The installations where I have been able to run QRO brick
on key and quick go check toroid temp have all been stone cold. Anyone has
contrary experience please let us know ASAP. We will certainly want to
investigate and determine why in one place and why not in another.
As to why he made his #2 powdered iron choice, Jerry Sevick W2FMI, covers
this convincingly in his book, pages 58-63, which I will NOT try to
reproduce on the reflector, as even if I did, I can't pass along the
essential graphs, photos and diagrams. ("Understanding, Building, and
Using Baluns and Ununs -- Theory and Practical Designs for the
Experimenter", Jerry Sevick W2FMI, Copyright 2003, CQ Communications, Inc.,
Hicksville, New York)
I have found, over the time that I have been working on top-band issues,
that dropping back after blowing something up and consulting W2FMI or his
material has been most valuable.
Alas, Jerry is a silent key, and I can no longer phone him to further
expound upon his choices. He particularly chose the large #2 powdered iron
cores for applications with a lot of stress on the core, particularly 160
"Because my simple loss measurements indicated that the higher permeability
powdered-irons had more loss than the No. 2 material, I decided to design a
4:1 Ruthroff Balun using this material--but with a larger core and more
turns than the McCoy Balun. Although McCoy's design has enjoyed
considerable success over the years, I felt that a larger inductive
reactance was desirable in order to assure better performance on the lower
frequency bands (particularly 160 meters). [Ibid p.59]
"I knew ... that loss with ferrite materials was related to the voltage
drop along the length of the [bifilar winding] and to the ...
permeability.
Permeabilities of 40 (No. 67 Ferrite) exhibited the lowest loss. ...
powdered iron #2 material with a permeability of 10 also showed the very
same low loss. Because powdered-iron material has been known to be more
rugged and linear than ferrite material, this suggested that other
powdered-irons ... should be investigated. ... However all four materials
showed a definite lower input impedance than #2 material, ..." [Ibid p.59]
Sevick had access to all of the ferrites, but did not choose any of them
for his monster hang-on-the-back-of-the-tuner 4:1 Balun, especially
intended to deal with wild voltages, very reactive loads, etc, and handle
them as well on 160 as 80-10. Instead Sevick chose the T400A-2 and #2
powdered iron to lay out there as his personal method. So we've done the
same. And everywhere we've used teflon-sleeved #14 double polyimide on the
#2 powdered iron cores, bad stuff has just quit happening, they work, and
they run stone cold.
At various scattered places in the book Sevick talks about all the issues
that come to bear on designing an isolation transformer on 160 meters. I
may not be able to develop a federal level proof case satisfactory so some,
but I am sticking with Mr. Sevick. His guidance has always panned out and
explained what was ailing. He did his high-stress 160 meter windings on
large #2 powdered iron toroids after research. So are we. We have the
hard-won results that prove out Sevick's and our choices.
73, Guy.
On Thu, Dec 15, 2011 at 2:58 PM, Rick Karlquist <richard at karlquist.com

Post by Guy Olinger K2AV

Post by Guy Olinger K2AV
Martin has the right instincts, says it feels fishy for this. But it's
worse than he thinks. And don't even consider using ferrites.
The T300A-2 core and 20 bifilar turns were SPECIFICALLY chosen to >

produce

Post by Guy Olinger K2AV
a
residual inductance value in the right order of magnitude to cancel a
typical residual capacitive reactance from a 160 meter 5/16 wave single
wire folded counterpoise, AND provide enough coupling to make the
transformer work, AND maintain a low enough loss to operate QRO without
heating, or especially to operate QRP without further handicapping the
operator with needless loss. This allows the builder of the "simple
solution" to prune the wire to get resonance and remain somewhere >

around
I'm trying to understand here what is magic about powdered iron.
It is true you can't just use any random piece of ferrite.
But if the T300A-2 were replaced with LOW PERMEABILITY ferrite
having the same permeability as a T300A-2 core, it would produce
the required residual inductance. The loss of low permeability
ferrite is extremely low, probably lower than powdered iron.
Coupling is a function of how the turns are wound, not the core material.
Am I missing something?
Rick N6RK
______________________________**_________________

UR RST IS ... ... ..9 QSB QSB - hw? BK
-----
No virus found in this message.
Checked by AVG - www.avg.com
Version: 10.0.1415 / Virus Database: 2108/4082 - Release Date: 12/15/11

[Guy Olinger K2AV]

Hi again, Carl

Unfortunately, there are a few pages out there that I do not wish to be on,
including some that say that everything has already been figured out, and
there is nothing new that will ever happen on 160. There are some
persuasive reasons to be thinking outside of this 80 year old box that 160
meters has been in.

To be really truthful, I have finally settled on a suspicious view of
nearly everything 160 meters. It has been remarkably useful to ask the
question "What if they are simply wrong, or there are substantial errors?"
I will keep my own counsel, AND all the other published lists beside the
one published by Micrometals. It's a free country and you are certainly
entitled to your viewpoints.

Good Luck and 73, Guy.

**
As I said earlier it always pays to go to the manufacturers data first
before relying upon and posting erroneous information. Micrometals explains
the caveats for deviating outside of the basic frequency ranges.
Try this and scroll to Radio Frequency Properties
http://www.micrometals.com/materials_index.html
BTW Mix 8 does not replace 6. However 7 was developed as the alternative
to be more temperature stable in use for VFO's and other critical circuits
thus the small diameters available.
Note also that Mix 0 is just that, there is no iron powder, its just a
phenolic donut and comes in handy at UHF
Free software is also available to take the guesswork out especially when
discussions get a bit confusing..
http://www.micrometals.com/software_index.html
We should all strive to be on the same page
Carl
KM1H
----- Original Message -----
*From:* Guy Olinger K2AV <olinger at bellsouth.net>
*To:* ZR <zr at jeremy.mv.com>
*Cc:* richard at karlquist.com ; topband at contesting.com ; Martin<hamradio at vr-web.de>
*Sent:* Thursday, December 15, 2011 11:43 PM
*Subject:* Re: Topband: T-200 vs. T-300
#2 powdered iron at mu of 10 is the lowest mu of the powdered iron types
listed with a frequency range that covers 160 meters (in some lists #2 is
2-30). You can rest assured Jerry Sevick had the list below. In his 160
meter comparison with #2 material, he tested 1,3,15 and 26. Number 6 really
doesn't work under 10 MHz, as specified in other lists. It's a "replaced"
mix that has had problems. Here's a composite list of powdered iron
materials from various incomplete sources.
0 Mix (Tan) 100-300 MHz u=1
1 Mix (Blue) 0.5-5 Mhz u=20
*2 Mix* (Red) 1-30 MHz, high volume resist. u=10 [Alt list 2-30 Mhz]
3 Mix (Gray) .05-.5 MHz, u=35
*6 Mix* (Yellow) 1-50 MHz, similar to mix #2. u=8 [alt list 10-50 MHz,
alt list use #8]
7 Mix 3-35 MHz, u=9 small cores only
*8 Mix *(Yellow / Red) 1-50 MHz, replaces 6 mix. u=35
10 Mix 30-100 MHz, u=6
12 Mix 50-200 MHz, u=4
15 Mix 0.1-2 MHz, u=25
*17 Mix* (Blue/Yellow) 50-200 MHz, good Q. u=3 [alt list u=4]
*18 Mix* (Green/Red) u=55, Low Core Loss, Similar to 8 Mix
*26 Mix* (Yellow/White) DC-800 KHz, great 60 Hz.
EMI range. Line 'em up on speakers / AC wires u=75
*40 Mix* (Green/Yellow) Power conversion similar to mix 26
*52 Mix* (Green/Blue) DC-1 MHz, high perm. u=75
73, Guy.

----- Original Message ----- From: "Guy Olinger K2AV" <
olinger at bellsouth.net>
To: <richard at karlquist.com>
Cc: <topband at contesting.com>; "Martin" <hamradio at vr-web.de>
Sent: Thursday, December 15, 2011 10:05 PM
Subject: Re: Topband: T-200 vs. T-300
Hi Rick,

Post by Guy Olinger K2AV
No magic. Just the right stuff, for the FCP, anyway.
To your particulars, when Jerry Sevick measured various ferrites, he
measured the lowest loss at mu=40. This was very low, as was the #2
powdered iron at mu=10, the lowest of the powdered iron formulas.

Since when is a 2 mix the lowest mu? It is ideal for QRO and HF since 6
and 7 mix arent made in QRO sizes and arent suitable at 160 anyway.
Carl
KM1H
So use

Post by Guy Olinger K2AV
of ferrites introduces a significantly reduced number of turns, with a much
more coarse granularity of possible inductive values, that has to be worked
out to use with the FCP, AND the behavior of the mu=40 core under highly
reactive loads is not spec'd by the manufacturer. The ferrite will have far
less radiating surface if it does heat up under extreme reactive load, AND
the length of the parallel bifilar wires may not be enough to cover 160
with the needed behavior in this app.
But my admonition about no ferrites has more to do with my knowing that
people have misc T240 and T200 form factor ferrites of ALL KINDS laying
around, and want to use the one they just found down in the junk box, which
does NOT have the material # or mu marked on it anywhere. And these
requests seem to pop up just before a contest, when most hope of getting
the correct stuff before contest has gone by the wayside. You will note
that I have pounded in Amidon T300A-2 #2 powdered iron toroid or strict
equivalent, over and over again. And I get back "please, please, please
tell me that I can use my junkbox ferrite toroid". But don't hold your
breath. In over four years of working with non-resonant antenna solutions
on 160, **NONE** of the ferrites we tried to use made it. We burnt or
cracked ALL of them at QRO. ALL of them. Really. Ferrite demolition
derby.
I have a new collection of #31 ferrite stuff, but I use those in low band
RFI suppression, not transformers. So I'm NOT going to tell anyone it's OK
to use a ferrite toroid for feeding an FCP.
Beyond that, what is NOT in doubt is that the #2 powdered iron choice works
and works well. The installations where I have been able to run QRO brick
on key and quick go check toroid temp have all been stone cold. Anyone has
contrary experience please let us know ASAP. We will certainly want to
investigate and determine why in one place and why not in another.
As to why he made his #2 powdered iron choice, Jerry Sevick W2FMI, covers
this convincingly in his book, pages 58-63, which I will NOT try to
reproduce on the reflector, as even if I did, I can't pass along the
essential graphs, photos and diagrams. ("Understanding, Building, and
Using Baluns and Ununs -- Theory and Practical Designs for the
Experimenter", Jerry Sevick W2FMI, Copyright 2003, CQ Communications, Inc.,
Hicksville, New York)
I have found, over the time that I have been working on top-band issues,
that dropping back after blowing something up and consulting W2FMI or his
material has been most valuable.
Alas, Jerry is a silent key, and I can no longer phone him to further
expound upon his choices. He particularly chose the large #2 powdered iron
cores for applications with a lot of stress on the core, particularly 160
"Because my simple loss measurements indicated that the higher permeability
powdered-irons had more loss than the No. 2 material, I decided to design a
4:1 Ruthroff Balun using this material--but with a larger core and more
turns than the McCoy Balun. Although McCoy's design has enjoyed
considerable success over the years, I felt that a larger inductive
reactance was desirable in order to assure better performance on the lower
frequency bands (particularly 160 meters). [Ibid p.59]
"I knew ... that loss with ferrite materials was related to the voltage
drop along the length of the [bifilar winding] and to the ... permeability.
Permeabilities of 40 (No. 67 Ferrite) exhibited the lowest loss. ...
powdered iron #2 material with a permeability of 10 also showed the very
same low loss. Because powdered-iron material has been known to be more
rugged and linear than ferrite material, this suggested that other
powdered-irons ... should be investigated. ... However all four materials
showed a definite lower input impedance than #2 material, ..." [Ibid p.59]
Sevick had access to all of the ferrites, but did not choose any of them
for his monster hang-on-the-back-of-the-tuner 4:1 Balun, especially
intended to deal with wild voltages, very reactive loads, etc, and handle
them as well on 160 as 80-10. Instead Sevick chose the T400A-2 and #2
powdered iron to lay out there as his personal method. So we've done the
same. And everywhere we've used teflon-sleeved #14 double polyimide on the
#2 powdered iron cores, bad stuff has just quit happening, they work, and
they run stone cold.
At various scattered places in the book Sevick talks about all the issues
that come to bear on designing an isolation transformer on 160 meters. I
may not be able to develop a federal level proof case satisfactory so some,
but I am sticking with Mr. Sevick. His guidance has always panned out and
explained what was ailing. He did his high-stress 160 meter windings on
large #2 powdered iron toroids after research. So are we. We have the
hard-won results that prove out Sevick's and our choices.
73, Guy.
On Thu, Dec 15, 2011 at 2:58 PM, Rick Karlquist <richard at karlquist.com

Post by Guy Olinger K2AV

Post by Guy Olinger K2AV
Martin has the right instincts, says it feels fishy for this. But

it's

Post by Guy Olinger K2AV
worse than he thinks. And don't even consider using ferrites.
The T300A-2 core and 20 bifilar turns were SPECIFICALLY chosen to >

produce

Post by Guy Olinger K2AV
a
residual inductance value in the right order of magnitude to cancel a
typical residual capacitive reactance from a 160 meter 5/16 wave

single

Post by Guy Olinger K2AV
wire folded counterpoise, AND provide enough coupling to make the
transformer work, AND maintain a low enough loss to operate QRO

without

Post by Guy Olinger K2AV
heating, or especially to operate QRP without further handicapping the
operator with needless loss. This allows the builder of the "simple
solution" to prune the wire to get resonance and remain somewhere >

around
I'm trying to understand here what is magic about powdered iron.
It is true you can't just use any random piece of ferrite.
But if the T300A-2 were replaced with LOW PERMEABILITY ferrite
having the same permeability as a T300A-2 core, it would produce
the required residual inductance. The loss of low permeability
ferrite is extremely low, probably lower than powdered iron.
Coupling is a function of how the turns are wound, not the core material.
Am I missing something?
Rick N6RK
______________________________**_________________

UR RST IS ... ... ..9 QSB QSB - hw? BK
-----
No virus found in this message.
Checked by AVG - www.avg.com
Version: 10.0.1415 / Virus Database: 2108/4082 - Release Date: 12/15/11

------------------------------
No virus found in this message.
Checked by AVG - www.avg.com
Version: 10.0.1415 / Virus Database: 2108/4082 - Release Date: 12/15/11

[Guy Olinger K2AV]

You may be right that Micrometals makes most of that stuff and sources
Amidon. But these are the individual company product numbers and you have
to use the company's own product numbers to order stuff from that given
company. You would need to take up Amidon's nomenclature choices with
Amidon.

Personally I am more annoyed that Amidon uses a different A sub L number
scheme than the rest of the world and has their own unique set of formulas.
Anyone knows how that came about, that would be interesting to know. 73,
Guy.

There is no such thing as an Amidon T-300 or any other toroid. In this
case they are just a reseller of Micrometals powered iron products.
Carl
KM1H
----- Original Message ----- From: "Guy Olinger K2AV" <
olinger at bellsouth.net>
To: "Martin" <hamradio at vr-web.de>
Cc: <topband at contesting.com>
Sent: Thursday, December 15, 2011 2:39 PM
Subject: Re: Topband: T-200 vs. T-300

Post by Guy Olinger K2AV
The Amidon T300A-2 can be replaced with a stacked PAIR of Amidon T300-2,
with a SINGLE Micrometals T300-2D, or a stacked PAIR of Micrometals T300-2.
You can find the Micrometals cores on eBay. You CAN use the Amidon
T400A-2, but that core is forty bux compared to the T300A-2's sixteen, and
I haven't figured the correct smaller number of turns to balance the FCP,
and since the T300A-2 does the job, why bother to blow 24 bux? Maybe for
5kW RF someone needs to do the work.

[Guy Olinger K2AV]

That's all well and good, but the closer one gets to the factory, the
larger the minimum. And it sure does get interesting if you just want to
buy one or two. I don't really care what Amidon is. They sell to hams in
small quantity. If anyone actually has a source, with a URL other than
Amidon, someone else who sells single quantities of what Amidon sells as
T300A-2 #2 powdered iron toroids, we all would LOVE to know. Micrometals
does not appear to sell retail. I see their stuff on eBay. Like a pair of
the Micrometals T300-2 which would fill the bill in a two core stack:

http://www.ebay.com/itm/MICROMETALS-T300-2-IRON-POWER-TOROID-3-CORE-PAIR-NEW-/130528349950?pt=LH_DefaultDomain_0&hash=item1e64188efe#ht_651wt_1104

73, Guy.

**
Amidon is not even a distributor, they are a reseller and buy from a
distributor so you pay a double markup.
For Fair-Rite they make up their own # such as FT240-61 since the other #
is long and hard to remember. With Micrometals they mostly just copy them.
If you want FACTORY data on any of them go to the FACTORY web site.
Carl
KM1H
----- Original Message -----
*From:* Guy Olinger K2AV <olinger at bellsouth.net>
*To:* ZR <zr at jeremy.mv.com>
*Cc:* Martin <hamradio at vr-web.de> ; topband at contesting.com
*Sent:* Thursday, December 15, 2011 5:52 PM
*Subject:* Re: Topband: T-200 vs. T-300
You may be right that Micrometals makes most of that stuff and sources
Amidon. But these are the individual company product numbers and you have
to use the company's own product numbers to order stuff from that given
company. You would need to take up Amidon's nomenclature choices with
Amidon.
Personally I am more annoyed that Amidon uses a different A sub L number
scheme than the rest of the world and has their own unique set of formulas.
Anyone knows how that came about, that would be interesting to know. 73,
Guy.

There is no such thing as an Amidon T-300 or any other toroid. In this
case they are just a reseller of Micrometals powered iron products.
Carl
KM1H
----- Original Message ----- From: "Guy Olinger K2AV" <
olinger at bellsouth.net>
To: "Martin" <hamradio at vr-web.de>
Cc: <topband at contesting.com>
Sent: Thursday, December 15, 2011 2:39 PM
Subject: Re: Topband: T-200 vs. T-300

Post by Guy Olinger K2AV
The Amidon T300A-2 can be replaced with a stacked PAIR of Amidon T300-2,
with a SINGLE Micrometals T300-2D, or a stacked PAIR of Micrometals T300-2.
You can find the Micrometals cores on eBay. You CAN use the Amidon
T400A-2, but that core is forty bux compared to the T300A-2's sixteen, and
I haven't figured the correct smaller number of turns to balance the FCP,
and since the T300A-2 does the job, why bother to blow 24 bux? Maybe for
5kW RF someone needs to do the work.

------------------------------
No virus found in this message.
Checked by AVG - www.avg.com
Version: 10.0.1415 / Virus Database: 2108/4082 - Release Date: 12/15/11

[W0UCE]

Here is a direct link to the Balun Designs FCP Transformer Page. A photo
and details will be on my website K2AV antenna page shortly.
73,
Jack


For those building an isolation transformer for a 160M 5/16 FCP -- PLEASE
READ! IMPORTANT!

Martin has the right instincts, says it feels fishy for this. But it's
worse than he thinks. And don't even consider using ferrites.

The T300A-2 core and 20 bifilar turns were SPECIFICALLY chosen to produce a
residual inductance value in the right order of magnitude to cancel a
typical residual capacitive reactance from a 160 meter 5/16 wave single
wire folded counterpoise, AND provide enough coupling to make the
transformer work, AND maintain a low enough loss to operate QRO without
heating, or especially to operate QRP without further handicapping the
operator with needless loss. This allows the builder of the "simple
solution" to prune the wire to get resonance and remain somewhere around an
ELECTRICAL quarter wave radiator. So this works for T's, L's, U's,
straight verticals, 1/8 wave-ish raised radials and HOA miscellaneous
stealth wires.

A T300 form factor is the minimum to wind 20 bifilar turns on the INSIDE
diameter. Twenty turns (forty wires) fills up the inside diameter. Less
than the T300A-2's 22.8 A sub L number (Amidon does not use the decimal
point) and residual inductance is reduced and doesn't match the FCP. Use
of a mu of 20 (#1 material) to pull this off on a smaller form factor with
fewer turns adds loss, and gets into heating.

FERRITES?? DO NOT use ferrites. This is a transformer, NOT a balun. There
is a voltage differential across the winding. The winding will go lossy.
We wind up overheating ferrites and cracking. This is not a balun with
guaranteed 100% cancelling counter-currents. Powdered iron is required.

The Amidon T300A-2 can be replaced with a stacked PAIR of Amidon T300-2,
with a SINGLE Micrometals T300-2D, or a stacked PAIR of Micrometals T300-2.
You can find the Micrometals cores on eBay. You CAN use the Amidon
T400A-2, but that core is forty bux compared to the T300A-2's sixteen, and
I haven't figured the correct smaller number of turns to balance the FCP,
and since the T300A-2 does the job, why bother to blow 24 bux? Maybe for
5kW RF someone needs to do the work.

My specification for results and success of design is predicated on the
particular design of isolation transformer. Move away from that and YOU
ARE ON YOUR OWN. Further, do not be deceived, to use the 5/16 wave FCP, an
isolation transformer is REQUIRED. We ALREADY TRIED using regular balun
designs to keep the counterpoise current off the feedline to an FCP. They
do not work in this app. Been there, done that. With the wrong kind of
dirt under the antenna, using a regular balun goes dummy load on you,
merely lossy otherwise. Don't try to feed this with a regular balun and
then come back and complain that it didn't work. OF COURSE it didn't work.
WE DISCOVERED it wouldn't work. WE TOLD YOU it wouldn't work.

Those of you carefully thinking this through could say that you could use a
series reactor AND a regular balun. Yeah, yeah, BUT this is now a straight
inductor on a core WITHOUT any counter-current to cut down on the losses.
So you lose big time on two counts: First, you only saved the cost of 7.5
feet of teflon on wire vs the isolation transformer, because you STILL had
to do core+single winding PLUS it also cost you the balun. Second, you
lost the fairly high percentage of counter-current cancellation using the
bifilar winding in the isolation transformer. So your coil plus regular
balun costs you more loss for QRP and heat for QRO.

If your beef is that it's too hard to make and get the right materials,
Balun Designs is making a model 1142s, which you can buy ready-made, now,
and does my full specification without any corner cutting. (I have no
financial interest in Balun Designs)
http://www.balundesigns.com/servlet/the-108/1-cln-1-High-Isolation-Balun/Det
ail


This is 160 meters, guys. You can't use the miniature stuff down here
without going lossy. You're talking about less money than taking the
family to a restaurant. Why bother with cheep cheep.

73, Guy K2AV (the inventor)

Post by Martin
For those who intend to build the FCP INV. L. with a T-200-2 (or an
antenna tuner).
Me and a few guys from our club wound different types of baluns and
chokes on different material and measured them with a
analyser. We found the T-200-2 next to useless below 3 Mhz due to a low
AL value (uH/100 turns). The T-200A-2 is a lot better, but still not
really good in balancing. You better use ferrites (FT-something) as long
as you use moderate power.
BUT if you go QRO, you should stick with the iron powder cores.
I once replaced the T-200-2 in my homebrew s-match with a ferrite. I
changed back the same day, cuz after a few seconds with 750W the ferrite
got so hot you would not want to touch it. The T-200-2 runs cool over an
entire contest. Next step is to replace it with a T-300A-2.
Below you find a list of cores with their corresponding Al Value.
You can clearly see that the T-300-2 is even lower than the T-200-2.
For the FCP INV L. i think a T-300A-2 or even better a T-400A-2 is best
choice, may it be expensive.
Core Al Value
T-200-2 120
T-200A-2 218
T-225-2 120
T-225A-2 215
T-300-2 114
T-300A-2 228
T-400-2 180
T-400A-2 360
I'm not a technician or rf-specialist and english is not my native
language, so please forgive me if my explanations are a bit ragged.
Yes, i use a T-200-2 in a tuner, which of course is not the same as an
antenna, but my feeling tells me i'm on the right track when i say that
a T-200-2 is no good choice for frequencies below 3Mhz,
http://toroids.info
http://www.qrz.lt/ly1gp/amidon.html
--
73, Martin DM4iM
_______________________________________________
UR RST IS ... ... ..9 QSB QSB - hw? BK

_______________________________________________
UR RST IS ... ... ..9 QSB QSB - hw? BK