= = = Telamon wrote in message
= = = ...
In article ,
(RHF) wrote:

CF,

Thank You - For the Link to "Fabricating Impedance {Matching}
Transformers for Receiving Antennas" - by John Bryant - May 2001
http://members.aol.com/DXerCapeCod/z_transformers.pdf

Good Reading and Worth Printing Out for Future Reference.

Now it looks like it is back to the Drawing Boards.

Guess I will make out a Spread Sheet for a couple of different
Ferrite Cores and start winding.

iane ~ RHF
.
.
= = = Conan Ford wrote in message
= = = 3.159...

This pdf is quite useful:
http://members.aol.com/DXerCapeCod/z_transformers.pdf

It takes you through how to do the calculations for any
torroid that you purchase.

Large torroids and Wire Wrap wire (solid core) are quite
effective and easy to handle.

I found that Type 43 material with even with windings for 2 mhz
and above is still quite effective for MW. Effective enough
that I get images on my Tecsun PL-550 between 2 mhz and 3 mhz
of distant MW broadcast stations that disappear when I unplug
the antenna.
.

I vote for MATERIAL K.

http://www.bytemark.com/products/ferrmat.htm


TELAMON,

Por "K" {Que} ?

iwtk ~ RHF
..
..

(RHF) wrote in message . com...

TIP: For a 9:1 Matching Transformer on a Toroidal (Donut) Ferrte Co

Use the right size Magnet Wire so that you have 83%/300* to
91%/330* Coverage of the Surface of the Ferrite's ID by the
Primary Winding of 30-33 Turns. Then on the Ferrite's OD
Surface take a Tooth Pick and use it to create a "Space" {Gap}
'between' every Third Turn of the Primary Windings.
[Three Turns + Space + Three Turns + Space + ETC]

The simply Overlay the Secondary Windings of 10-11 Truns; using the
"Space" {Gap} in Ferrite's OD Primary Windings as your WRAP-GAGE.

iane ~ RHF

Not to be a wet blanket - but if I am reading this right, to make a
space every third turn would *not* yield a nice neat corridor for that
10-turn wire - each turn, it would cross the other three *once*.
Maybe this is OK, and the turn spacing is crucial, not whether or not
the wires overlap.

I have no doubt that the method RHF describes is very effective, and
perhaps the best - but it seems to not be the only way to do it.

The method shown by CW on his website simply shows a neat wrap of 30,
connected at ground to the 1/3-overlapping neat wrap of 10, with no
particular spacing (in fact, CW has stated that neatness isn't all
that critical, although intuition suggests that neatness and evenness
must be of some value). Others suggest that the wraps need not be one
atop the other, but in tandem along the core.

I wonder how one without specialized measuring devices could determine
which method is optimal - but maybe that is splitting hairs.

Bruce Jensen

bpnjensen wrote:

(RHF) wrote in message . com...

TIP: For a 9:1 Matching Transformer on a Toroidal (Donut) Ferrte Co

Use the right size Magnet Wire so that you have 83%/300* to
91%/330* Coverage of the Surface of the Ferrite's ID by the
Primary Winding of 30-33 Turns. Then on the Ferrite's OD
Surface take a Tooth Pick and use it to create a "Space" {Gap}
'between' every Third Turn of the Primary Windings.
[Three Turns + Space + Three Turns + Space + ETC]

The simply Overlay the Secondary Windings of 10-11 Truns; using the
"Space" {Gap} in Ferrite's OD Primary Windings as your WRAP-GAGE.

iane ~ RHF

Not to be a wet blanket - but if I am reading this right, to make a
space every third turn would *not* yield a nice neat corridor for that
10-turn wire - each turn, it would cross the other three *once*.
Maybe this is OK, and the turn spacing is crucial, not whether or not
the wires overlap.

I have no doubt that the method RHF describes is very effective, and
perhaps the best - but it seems to not be the only way to do it.

The method shown by CW on his website simply shows a neat wrap of 30,
connected at ground to the 1/3-overlapping neat wrap of 10, with no
particular spacing (in fact, CW has stated that neatness isn't all
that critical, although intuition suggests that neatness and evenness
must be of some value). Others suggest that the wraps need not be one
atop the other, but in tandem along the core.

I wonder how one without specialized measuring devices could determine
which method is optimal - but maybe that is splitting hairs.

Splitting hairs. The method CW shows will work just fine.

Some folks just try to over engineer things.

dxAce
Michigan
USA

BPNJ,

I was simply trying to 'describe' in "Words":
What one might 'see' in a Picture / Image
and attempt to "Copy" as best as they could.

1. Cover the Ferrite Core 300*-330* with the Primary Winding.

2. Wrap the Primary Tightly and Evenly around the Ferrite Core.

3. Wrap the Secondary Tightly and Evenly over the Primary.

nothing more ~ RHF
..
..
= = = (bpnjensen) wrote in message
= = = . com...
(RHF) wrote in message . com...

TIP: For a 9:1 Matching Transformer on a Toroidal (Donut) Ferrte Co

Use the right size Magnet Wire so that you have 83%/300* to
91%/330* Coverage of the Surface of the Ferrite's ID by the
Primary Winding of 30-33 Turns. Then on the Ferrite's OD
Surface take a Tooth Pick and use it to create a "Space" {Gap}
'between' every Third Turn of the Primary Windings.
[Three Turns + Space + Three Turns + Space + ETC]

The simply Overlay the Secondary Windings of 10-11 Truns; using the
"Space" {Gap} in Ferrite's OD Primary Windings as your WRAP-GAGE.

iane ~ RHF

Not to be a wet blanket - but if I am reading this right, to make a
space every third turn would *not* yield a nice neat corridor for that
10-turn wire - each turn, it would cross the other three *once*.
Maybe this is OK, and the turn spacing is crucial, not whether or not
the wires overlap.

I have no doubt that the method RHF describes is very effective, and
perhaps the best - but it seems to not be the only way to do it.

The method shown by CW on his website simply shows a neat wrap of 30,
connected at ground to the 1/3-overlapping neat wrap of 10, with no
particular spacing (in fact, CW has stated that neatness isn't all
that critical, although intuition suggests that neatness and evenness
must be of some value). Others suggest that the wraps need not be one
atop the other, but in tandem along the core.

I wonder how one without specialized measuring devices could determine
which method is optimal - but maybe that is splitting hairs.

Bruce Jensen