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• Re: Quick question about winding Transformers

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• Hi Alan and all, I read that page several times before sending my first email, but it does not deal with how to interpret this very cryptic statement: 0.69uH:
Jan 21 1 of 13
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Hi Alan and all,

I read that page several times before sending my first email, but it does not deal with how to interpret this very cryptic statement:

0.69uH: 16T/2x8T bifilar #30 on T25-6 (yellow) 9" (top)

As this sort of statement is used in the build instructions it would be a very good idea to show the poor suffering (non scientist!) ham builder how to interpret it. Preferably right there in the build notes, not off on some link elsewhere. (the page already has all sorts of information, so why not add this?)

Look at this: "16T/2x8T" How are we to interpret this? 16 turns divided by 2? Multiplied by 8 turns? A little English goes a long way to clearing up confusion. After a lot of extra reading in this forum I THINK I've figured it out:

16 turns of #30 on a T25-6, using 9" of wire.
Then take another 9" of wire (not mentioned in the instructions) and cut it in two. Twist the resulting two pieces together then add to the T25-6 as 8 turns overlapping the 16 turns already added.

In the specific step in question the text in the "Component Top/Bottom" column could be changed to something like:

16T #30 9", 8T bifilar 2x4.5" #30, on T25-6 (yellow)(top)

Using text that minimizes confusion results in a lot fewer questions on the forum, lower stress level for those involved, and a higher success ratio on the project.

I realize that lots of volunteers have been doing their best on this over a period of several years, but when you get too close to the project you can lose perspective and think that something like "0.69uH: 16T/2x8T bifilar #30 on T25-6 (yellow) 9" (top)" makes total sense to everyone...

Joel VE6EI

--- In softrock40@yahoogroups.com, "Alan" wrote:
>
>
> ----- Original Message -----
> Subject: [softrock40] Re: Quick question about winding Transformers
>
>
> >I presume this question is about winding of T5 in the RxTx? I'm trying to interpret this myself and it is simply not in the least
> >clear, either in the cryptic code-like way of describing the winding process in the "Component Top/Bottom" column in the
> >instructions, or anywhere else on the website that I've yet found.
> >
> > I'm pretty darn sure that T5 is a source of frustration for a lot of builders. How about adding a note IN THE BUILD INSTRUCTIONS
> > explaining clearly how to wind it? This email chain is the only place I've seen anything about it but even here I'm not 100% sure
> > what to do...
> >
>
> Joel,
>
> There is a link to this page http://www.wb5rvz.com/sdr/common/Common_Component_Mounting.htm#toroid_coils which has information and
> If this is not enough then let us know.
> If the link is not on the page where you were looking let Robby know.
>
> 73 Alan G4ZFQ
>
• ... Subject: [softrock40] Re: Quick question about winding Transformers ... Joel, As I ve never followed Robby s instructions I m not familiar with following
Jan 21 1 of 13
View Source
----- Original Message -----
Subject: [softrock40] Re: Quick question about winding Transformers

> I read that page several times before sending my first email, but it does not deal with how to interpret this very cryptic
> statement:
>
> 0.69uH: 16T/2x8T bifilar #30 on T25-6 (yellow) 9" (top)
>

Joel,

As I've never followed Robby's instructions I'm not familiar with following them But on the page I linked is:-

"Specification Format
Winding specs will generally resemble the following:

5.0 uH 17T bifilar/34T #30 on T30-2 (red) (19").

This can be interpreted as:

a.. Use a T30-2 toroid (color is red and O.D. is 0.3")
b.. You will need two 19" lengths of #30 wire.
c.. For toroids, one turn is a single pass through the center hole.
d.. For binocular cores, one turn is a pass in which the wire goes in the bottom, comes out the top, goes back in the other hole
at the top, and comes out the other hole at the bottom.
e.. The transformer will have a single, 34 turn, secondary winding of 19" of #30 wire. Usually the single winiding is wound onto
the core first. Winding should be evenly spaced and ideally cover all but a 15 degree "wedge" of the toroid. Sometimes, it may be
necessary to wind over the top of existing turns where there is more wire than there is bare core left.
f.. The transformer will have two primary windings each of 17 turns of #30 wire. The term "bifilar" means to take one of the two
lengths of wire, bend it at the half-point so the resultant "hairpin" is composed of the two 9.5" long halves, and then twist the
two strands together to make a "bifilar" strand with approximately 3 twists to the inch. The bifilar windings are usually wound
AFTER (and over) the single strand winding. You should wait until you have wound it correctly before cutting the "hairpin" end of
the bifilar strand.
g.. The inductance value is provided primarily to help validate the number of turns. It is the inductance of the single-strand
winding"
Which to me seems to give a reasonable idea. And the other links on that page must give more information.
Once you have done one then it seems uneccessary to repeat the instructions. It is a one-time learning procedure.
Many others have made the coils before with only a few asking about them.
However, if you feel Robby should make things clearer then I'm sure he will be glad to discuss it with you.

73 Alan G4ZFQ

>
• I have modified the build instructions such that, in each step calling for the installation of an inductor, I print out an expanded winding instruction. For
Jan 22 1 of 13
View Source
I have modified the build instructions such that, in each step calling for the installation of an inductor, I print out an expanded winding instruction.  For example, in the step calling for the installation of the T5 transformer in the RXTX Ensemble, the instruction is:
"T5
XFRMR: 0.6uH: 14T/2x7T bifilar #30 on T25-6 (yellow) 8"
Primary: Using approximately 9 inches of #30 wire, wind 14 turns on a T25-6 (yellow) ferrite.
Secondary: Using a total of 9 inches of #30 wire, wind 7 turns , bifilar, on the ferrite in the same direction as the primary winding. Inductance of the single winding (usually the primary) is 0.60 uH."

The instructions are computer-generated and may have rounding errors in the computed wire lengths (e.g., in the above the shorthand version says 8"; the generated version says 9").  I conservatively round up.

If you are not seing this in the build instructions, please refresh the page in your browser (F5) to remove any cached older pages.

I am open to suggestions as to how I should re-program the instruction generation algorithms for more clarity.

Since I maintain this website and its associated infrastructure at no cost to the consumer of its instructions and receive no compensation for any of my labors or outlays, I am somewhat limited by my other commitments in my ability to respond as promptly as some might otherwise wish.

On Mon, Jan 21, 2013 at 12:54 PM, Alan wrote:

----- Original Message -----
Subject: [softrock40] Re: Quick question about winding Transformers

> I read that page several times before sending my first email, but it does not deal with how to interpret this very cryptic
> statement:
>
> 0.69uH: 16T/2x8T bifilar #30 on T25-6 (yellow) 9" (top)
>

Joel,

As I've never followed Robby's instructions I'm not familiar with following them But on the page I linked is:-

"Specification Format
Winding specs will generally resemble the following:

5.0 uH 17T bifilar/34T #30 on T30-2 (red) (19").

This can be interpreted as:

a.. Use a T30-2 toroid (color is red and O.D. is 0.3")
b.. You will need two 19" lengths of #30 wire.
c.. For toroids, one turn is a single pass through the center hole.
d.. For binocular cores, one turn is a pass in which the wire goes in the bottom, comes out the top, goes back in the other hole
at the top, and comes out the other hole at the bottom.
e.. The transformer will have a single, 34 turn, secondary winding of 19" of #30 wire. Usually the single winiding is wound onto
the core first. Winding should be evenly spaced and ideally cover all but a 15 degree "wedge" of the toroid. Sometimes, it may be
necessary to wind over the top of existing turns where there is more wire than there is bare core left.
f.. The transformer will have two primary windings each of 17 turns of #30 wire. The term "bifilar" means to take one of the two
lengths of wire, bend it at the half-point so the resultant "hairpin" is composed of the two 9.5" long halves, and then twist the
two strands together to make a "bifilar" strand with approximately 3 twists to the inch. The bifilar windings are usually wound
AFTER (and over) the single strand winding. You should wait until you have wound it correctly before cutting the "hairpin" end of
the bifilar strand.
g.. The inductance value is provided primarily to help validate the number of turns. It is the inductance of the single-strand
winding"
Which to me seems to give a reasonable idea. And the other links on that page must give more information.
Once you have done one then it seems uneccessary to repeat the instructions. It is a one-time learning procedure.
Many others have made the coils before with only a few asking about them.
However, if you feel Robby should make things clearer then I'm sure he will be glad to discuss it with you.

73 Alan G4ZFQ

>

--
Cheers,
Robby

Richard R. (Robby) Robson
LTC USA (RET)
• Robby, Thanks for taking the time to do some updating. when you say bifilar I understand that as two wires, with all of the documentation out there and
Jan 22 1 of 13
View Source
Robby, Thanks for taking the time to do some updating.  when you say bifilar I understand that as two wires, with all of the documentation out there and comments on the list I find myself wondering:  when you say a length are the instructions always talking total length required and bifilar always means then bent in half before winding, also when you way bifilar are you talking 3 twists per inch?  I think these type of things are causing people difficulty.  I know in my case (very knowledgeable  I find myself reading several time just to make sure I understand what is required..   Perhaps general things like this should be stated at the beginning of the build.

Just last night I realized that I had two sizes of wire, didn't notice there was a difference other than color.  so I have wound 3 inductors with the wrong size.  How did this happen, I missed it when reading, also the "finished pictures" showed red wire.  when complete the rxtx I will decide if the inductance change because of wire size will effect performance.  I have all of the test equipment required to analze this.. its just an irritance at this point, but am enjoying myself..  regards.. Fred

On Tue, Jan 22, 2013 at 9:33 AM, R. R. (Robby) Robson wrote:

I have modified the build instructions such that, in each step calling for the installation of an inductor, I print out an expanded winding instruction.  For example, in the step calling for the installation of the T5 transformer in the RXTX Ensemble, the instruction is:

"T5
XFRMR: 0.6uH: 14T/2x7T bifilar #30 on T25-6 (yellow) 8"
Primary: Using approximately 9 inches of #30 wire, wind 14 turns on a T25-6 (yellow) ferrite.
Secondary: Using a total of 9 inches of #30 wire, wind 7 turns , bifilar, on the ferrite in the same direction as the primary winding. Inductance of the single winding (usually the primary) is 0.60 uH."

The instructions are computer-generated and may have rounding errors in the computed wire lengths (e.g., in the above the shorthand version says 8"; the generated version says 9").  I conservatively round up.

If you are not seing this in the build instructions, please refresh the page in your browser (F5) to remove any cached older pages.

I am open to suggestions as to how I should re-program the instruction generation algorithms for more clarity.

Since I maintain this website and its associated infrastructure at no cost to the consumer of its instructions and receive no compensation for any of my labors or outlays, I am somewhat limited by my other commitments in my ability to respond as promptly as some might otherwise wish.

On Mon, Jan 21, 2013 at 12:54 PM, Alan wrote:

----- Original Message -----
Subject: [softrock40] Re: Quick question about winding Transformers

> I read that page several times before sending my first email, but it does not deal with how to interpret this very cryptic
> statement:
>
> 0.69uH: 16T/2x8T bifilar #30 on T25-6 (yellow) 9" (top)
>

Joel,

As I've never followed Robby's instructions I'm not familiar with following them But on the page I linked is:-

"Specification Format
Winding specs will generally resemble the following:

5.0 uH 17T bifilar/34T #30 on T30-2 (red) (19").

This can be interpreted as:

a.. Use a T30-2 toroid (color is red and O.D. is 0.3")
b.. You will need two 19" lengths of #30 wire.
c.. For toroids, one turn is a single pass through the center hole.
d.. For binocular cores, one turn is a pass in which the wire goes in the bottom, comes out the top, goes back in the other hole
at the top, and comes out the other hole at the bottom.
e.. The transformer will have a single, 34 turn, secondary winding of 19" of #30 wire. Usually the single winiding is wound onto
the core first. Winding should be evenly spaced and ideally cover all but a 15 degree "wedge" of the toroid. Sometimes, it may be
necessary to wind over the top of existing turns where there is more wire than there is bare core left.
f.. The transformer will have two primary windings each of 17 turns of #30 wire. The term "bifilar" means to take one of the two
lengths of wire, bend it at the half-point so the resultant "hairpin" is composed of the two 9.5" long halves, and then twist the
two strands together to make a "bifilar" strand with approximately 3 twists to the inch. The bifilar windings are usually wound
AFTER (and over) the single strand winding. You should wait until you have wound it correctly before cutting the "hairpin" end of
the bifilar strand.
g.. The inductance value is provided primarily to help validate the number of turns. It is the inductance of the single-strand
winding"
Which to me seems to give a reasonable idea. And the other links on that page must give more information.
Once you have done one then it seems uneccessary to repeat the instructions. It is a one-time learning procedure.
Many others have made the coils before with only a few asking about them.
However, if you feel Robby should make things clearer then I'm sure he will be glad to discuss it with you.

73 Alan G4ZFQ

>

--
Cheers,
Robby

Richard R. (Robby) Robson
LTC USA (RET)

--
Fred Moore
Email: fred@...
Cell: 321-217-8699
• Fred: Thanks for the info. I can t do too much about the colors of the wires - I m red-green colorblind. I ll look into some rework to include the twists and
Jan 22 1 of 13
View Source
Fred:
Thanks for the info.  I can't do too much about the colors of the wires - I'm red-green colorblind.
I'll look into some rework to include the twists and the approach to making a bifilar strand.

On Tue, Jan 22, 2013 at 9:16 AM, Fred Moore <fred@...> wrote:

Robby, Thanks for taking the time to do some updating.  when you say bifilar I understand that as two wires, with all of the documentation out there and comments on the list I find myself wondering:  when you say a length are the instructions always talking total length required and bifilar always means then bent in half before winding, also when you way bifilar are you talking 3 twists per inch?  I think these type of things are causing people difficulty.  I know in my case (very knowledgeable  I find myself reading several time just to make sure I understand what is required..   Perhaps general things like this should be stated at the beginning of the build.

Just last night I realized that I had two sizes of wire, didn't notice there was a difference other than color.  so I have wound 3 inductors with the wrong size.  How did this happen, I missed it when reading, also the "finished pictures" showed red wire.  when complete the rxtx I will decide if the inductance change because of wire size will effect performance.  I have all of the test equipment required to analze this.. its just an irritance at this point, but am enjoying myself..  regards.. Fred

On Tue, Jan 22, 2013 at 9:33 AM, R. R. (Robby) Robson wrote:

I have modified the build instructions such that, in each step calling for the installation of an inductor, I print out an expanded winding instruction.  For example, in the step calling for the installation of the T5 transformer in the RXTX Ensemble, the instruction is:

"T5
XFRMR: 0.6uH: 14T/2x7T bifilar #30 on T25-6 (yellow) 8"
Primary: Using approximately 9 inches of #30 wire, wind 14 turns on a T25-6 (yellow) ferrite.
Secondary: Using a total of 9 inches of #30 wire, wind 7 turns , bifilar, on the ferrite in the same direction as the primary winding. Inductance of the single winding (usually the primary) is 0.60 uH."

The instructions are computer-generated and may have rounding errors in the computed wire lengths (e.g., in the above the shorthand version says 8"; the generated version says 9").  I conservatively round up.

If you are not seing this in the build instructions, please refresh the page in your browser (F5) to remove any cached older pages.

I am open to suggestions as to how I should re-program the instruction generation algorithms for more clarity.

Since I maintain this website and its associated infrastructure at no cost to the consumer of its instructions and receive no compensation for any of my labors or outlays, I am somewhat limited by my other commitments in my ability to respond as promptly as some might otherwise wish.

On Mon, Jan 21, 2013 at 12:54 PM, Alan wrote:

----- Original Message -----
Subject: [softrock40] Re: Quick question about winding Transformers

> I read that page several times before sending my first email, but it does not deal with how to interpret this very cryptic
> statement:
>
> 0.69uH: 16T/2x8T bifilar #30 on T25-6 (yellow) 9" (top)
>

Joel,

As I've never followed Robby's instructions I'm not familiar with following them But on the page I linked is:-

"Specification Format
Winding specs will generally resemble the following:

5.0 uH 17T bifilar/34T #30 on T30-2 (red) (19").

This can be interpreted as:

a.. Use a T30-2 toroid (color is red and O.D. is 0.3")
b.. You will need two 19" lengths of #30 wire.
c.. For toroids, one turn is a single pass through the center hole.
d.. For binocular cores, one turn is a pass in which the wire goes in the bottom, comes out the top, goes back in the other hole
at the top, and comes out the other hole at the bottom.
e.. The transformer will have a single, 34 turn, secondary winding of 19" of #30 wire. Usually the single winiding is wound onto
the core first. Winding should be evenly spaced and ideally cover all but a 15 degree "wedge" of the toroid. Sometimes, it may be
necessary to wind over the top of existing turns where there is more wire than there is bare core left.
f.. The transformer will have two primary windings each of 17 turns of #30 wire. The term "bifilar" means to take one of the two
lengths of wire, bend it at the half-point so the resultant "hairpin" is composed of the two 9.5" long halves, and then twist the
two strands together to make a "bifilar" strand with approximately 3 twists to the inch. The bifilar windings are usually wound
AFTER (and over) the single strand winding. You should wait until you have wound it correctly before cutting the "hairpin" end of
the bifilar strand.
g.. The inductance value is provided primarily to help validate the number of turns. It is the inductance of the single-strand
winding"
Which to me seems to give a reasonable idea. And the other links on that page must give more information.
Once you have done one then it seems uneccessary to repeat the instructions. It is a one-time learning procedure.
Many others have made the coils before with only a few asking about them.
However, if you feel Robby should make things clearer then I'm sure he will be glad to discuss it with you.

73 Alan G4ZFQ

>

--
Cheers,
Robby

Richard R. (Robby) Robson
LTC USA (RET)

--
Fred Moore
Email: fred@...

--
Cheers,
Robby

Richard R. (Robby) Robson
LTC USA (RET)
• Thanks so much for making these improvements to the build instructions! The algorithm may not be perfect but it s pretty darn impressive! Joel VE6EI
Jan 22 1 of 13
View Source
Thanks so much for making these improvements to the build instructions! The algorithm may not be perfect but it's pretty darn impressive!

Joel VE6EI

--- In softrock40@yahoogroups.com, "R. R. (Robby) Robson" wrote:
>
> I have modified the build instructions such that, in each step calling for
> the installation of an inductor, I print out an expanded winding
> instruction. For example, in the step calling for the installation of the
> T5 transformer in the RXTX
> Ensemble, the instruction is:
> "T5
> XFRMR: 0.6uH: 14T/2x7T bifilar #30 on T25-6 (yellow) 8"
> Primary: Using approximately 9 inches of #30 wire, wind 14 turns on a T25-6
> (yellow) ferrite.
> Secondary: Using a total of 9 inches of #30 wire, wind 7 turns , bifilar,
> on the ferrite in the same direction as the primary winding. Inductance of
> the single winding (usually the primary) is 0.60 uH."
>
> The instructions are computer-generated and may have rounding errors in the
> computed wire lengths (e.g., in the above the shorthand version says 8";
> the generated version says 9"). I conservatively round up.
>
> If you are not seing this in the build instructions, please refresh the
> page in your browser (F5) to remove any cached older pages.
>
> I am open to suggestions as to how I should re-program the instruction
> generation algorithms for more clarity.
>
> Since I maintain this website and its associated infrastructure at no cost
> to the consumer of its instructions and receive no compensation for any of
> my labors or outlays, I am somewhat limited by my other commitments in my
> ability to respond as promptly as some might otherwise wish.
>
> On Mon, Jan 21, 2013 at 12:54 PM, Alan wrote:
>
> > **
> >
> >
> >
> > ----- Original Message -----
> > Subject: [softrock40] Re: Quick question about winding Transformers
> >
> > > I read that page several times before sending my first email, but it
> > does not deal with how to interpret this very cryptic
> > > statement:
> > >
> > > 0.69uH: 16T/2x8T bifilar #30 on T25-6 (yellow) 9" (top)
> > >
> >
> > Joel,
> >
> > As I've never followed Robby's instructions I'm not familiar with
> > following them But on the page I linked is:-
> >
> > "Specification Format
> > Winding specs will generally resemble the following:
> >
> > 5.0 uH 17T bifilar/34T #30 on T30-2 (red) (19").
> >
> > This can be interpreted as:
> >
> > a.. Use a T30-2 toroid (color is red and O.D. is 0.3")
> > b.. You will need two 19" lengths of #30 wire.
> > c.. For toroids, one turn is a single pass through the center hole.
> > d.. For binocular cores, one turn is a pass in which the wire goes in the
> > bottom, comes out the top, goes back in the other hole
> > at the top, and comes out the other hole at the bottom.
> > e.. The transformer will have a single, 34 turn, secondary winding of 19"
> > of #30 wire. Usually the single winiding is wound onto
> > the core first. Winding should be evenly spaced and ideally cover all but
> > a 15 degree "wedge" of the toroid. Sometimes, it may be
> > necessary to wind over the top of existing turns where there is more wire
> > than there is bare core left.
> > f.. The transformer will have two primary windings each of 17 turns of #30
> > wire. The term "bifilar" means to take one of the two
> > lengths of wire, bend it at the half-point so the resultant "hairpin" is
> > composed of the two 9.5" long halves, and then twist the
> > two strands together to make a "bifilar" strand with approximately 3
> > twists to the inch. The bifilar windings are usually wound
> > AFTER (and over) the single strand winding. You should wait until you have
> > wound it correctly before cutting the "hairpin" end of
> > the bifilar strand.
> > g.. The inductance value is provided primarily to help validate the number
> > of turns. It is the inductance of the single-strand
> > winding"
> > Which to me seems to give a reasonable idea. And the other links on that
> > page must give more information.
> > Once you have done one then it seems uneccessary to repeat the
> > instructions. It is a one-time learning procedure.
> > Many others have made the coils before with only a few asking about them.
> > However, if you feel Robby should make things clearer then I'm sure he
> > will be glad to discuss it with you.
> >
> > 73 Alan G4ZFQ
> >
> > >
> >
> >
> >
>
>
>
> --
> Cheers,
> Robby
>
> Richard R. (Robby) Robson
> LTC USA (RET)
> www.wb5rvz.com
> www.wb5rvz.org
> www.rafino.org
>
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