I need a SWAG on this, just to see if it's feasible...

Two inductors (solenoids) with Ferrite cores, each ~5mm in diameter
and separated by ~5mm spacing.

What coupling coefficient might I expect?

(Essentially no load on the "receiving" inductor except natural
losses... and I could tune or not.)

...Jim Thompson
--
| James E.Thompson | mens |
| Analog Innovations | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| San Tan Valley, AZ 85142 Skype: skypeanalog | |
| Voice480)460-2350 Fax: Available upon request | Brass Rat |
| E-mail Icon at http://www.analog-innovations.com | 1962 |

I love to cook with wine. Sometimes I even put it in the food.

On Sun, 12 Oct 2014 12:45:29 -0700, Jim Thompson
wrote:

I need a SWAG on this, just to see if it's feasible...

Two inductors (solenoids) with Ferrite cores, each ~5mm in diameter
and separated by ~5mm spacing.

What coupling coefficient might I expect?

(Essentially no load on the "receiving" inductor except natural
losses... and I could tune or not.)

...Jim Thompson


how long?

On Sun, 12 Oct 2014 12:45:29 -0700, Jim Thompson
wrote:

I need a SWAG on this, just to see if it's feasible...

Two inductors (solenoids) with Ferrite cores, each ~5mm in diameter
and separated by ~5mm spacing.

What coupling coefficient might I expect?

(Essentially no load on the "receiving" inductor except natural
losses... and I could tune or not.)

...Jim Thompson

5mm rods, how long? what orientation? end to end? side by side?

audio ferrites? low perm ferrites?

On Sun, 12 Oct 2014 13:17:04 -0700, RobertMacy
wrote:

On Sun, 12 Oct 2014 12:45:29 -0700, Jim Thompson
wrote:

I need a SWAG on this, just to see if it's feasible...

Two inductors (solenoids) with Ferrite cores, each ~5mm in diameter
and separated by ~5mm spacing.

What coupling coefficient might I expect?

(Essentially no load on the "receiving" inductor except natural
losses... and I could tune or not.)

...Jim Thompson

5mm rods, how long? what orientation? end to end? side by side?

audio ferrites? low perm ferrites?

I don't know. What would be best? ~100kHz sinusoidal drive

...Jim Thompson
--
| James E.Thompson | mens |
| Analog Innovations | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| San Tan Valley, AZ 85142 Skype: skypeanalog | |
| Voice480)460-2350 Fax: Available upon request | Brass Rat |
| E-mail Icon at http://www.analog-innovations.com | 1962 |

I love to cook with wine. Sometimes I even put it in the food.

On Sun, 12 Oct 2014 13:25:32 -0700, Jim Thompson
wrote:

On Sun, 12 Oct 2014 13:17:04 -0700, RobertMacy
wrote:

On Sun, 12 Oct 2014 12:45:29 -0700, Jim Thompson
wrote:

I need a SWAG on this, just to see if it's feasible...

Two inductors (solenoids) with Ferrite cores, each ~5mm in diameter
and separated by ~5mm spacing.

What coupling coefficient might I expect?

(Essentially no load on the "receiving" inductor except natural
losses... and I could tune or not.)

...Jim Thompson

5mm rods, how long? what orientation? end to end? side by side?

audio ferrites? low perm ferrites?

I don't know. What would be best? ~100kHz sinusoidal drive

...Jim Thompson

obviously, best orientation depends on length.

from memory rods usually are 4:1 up to 10:1 aspect ratio rarely longer,
they break pretty easily. surprisingly the aspect ratio determines more
the 'effective' permeability much more than the basic permeability, like
with a 4:1 anything with more than 100 rel perm makes NO difference.

do you have any way to 'close' the magnetic path just a bit? Tuning makes
a BIG difference! on getting a huge voltage out of it.

I can make some 'guesses' or spend some time to look at it in a bit more
detail over night and get back to you with justifications for why do this
versus do that.

Cross talk you can get some good estimates. If this is for a
'communication' at all; we should discuss that a bit too.

On Sun, 12 Oct 2014 14:03:08 -0700, RobertMacy
wrote:

On Sun, 12 Oct 2014 13:25:32 -0700, Jim Thompson
wrote:

On Sun, 12 Oct 2014 13:17:04 -0700, RobertMacy
wrote:

On Sun, 12 Oct 2014 12:45:29 -0700, Jim Thompson
wrote:

I need a SWAG on this, just to see if it's feasible...

Two inductors (solenoids) with Ferrite cores, each ~5mm in diameter
and separated by ~5mm spacing.

What coupling coefficient might I expect?

(Essentially no load on the "receiving" inductor except natural
losses... and I could tune or not.)

...Jim Thompson

5mm rods, how long? what orientation? end to end? side by side?

audio ferrites? low perm ferrites?

I don't know. What would be best? ~100kHz sinusoidal drive

...Jim Thompson

obviously, best orientation depends on length.

from memory rods usually are 4:1 up to 10:1 aspect ratio rarely longer,
they break pretty easily. surprisingly the aspect ratio determines more
the 'effective' permeability much more than the basic permeability, like
with a 4:1 anything with more than 100 rel perm makes NO difference.

do you have any way to 'close' the magnetic path just a bit? Tuning makes
a BIG difference! on getting a huge voltage out of it.

I can make some 'guesses' or spend some time to look at it in a bit more
detail over night and get back to you with justifications for why do this
versus do that.

Cross talk you can get some good estimates. If this is for a
'communication' at all; we should discuss that a bit too.

This is an RFQ for a slow speed (~100bps) data link "magnetically",
with ~5mm gap.

I'm just wondering feasibility before sticking my neck out.

...Jim Thompson
--
| James E.Thompson | mens |
| Analog Innovations | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| San Tan Valley, AZ 85142 Skype: skypeanalog | |
| Voice480)460-2350 Fax: Available upon request | Brass Rat |
| E-mail Icon at http://www.analog-innovations.com | 1962 |

I love to cook with wine. Sometimes I even put it in the food.

On Sun, 12 Oct 2014 14:14:53 -0700, Jim Thompson
wrote:

On Sun, 12 Oct 2014 14:03:08 -0700, RobertMacy
wrote:

On Sun, 12 Oct 2014 13:25:32 -0700, Jim Thompson
wrote:

On Sun, 12 Oct 2014 13:17:04 -0700, RobertMacy
wrote:

On Sun, 12 Oct 2014 12:45:29 -0700, Jim Thompson
wrote:

I need a SWAG on this, just to see if it's feasible...

Two inductors (solenoids) with Ferrite cores, each ~5mm in diameter
and separated by ~5mm spacing.

What coupling coefficient might I expect?

(Essentially no load on the "receiving" inductor except natural
losses... and I could tune or not.)

...Jim Thompson

5mm rods, how long? what orientation? end to end? side by side?

audio ferrites? low perm ferrites?

I don't know. What would be best? ~100kHz sinusoidal drive

...Jim Thompson

obviously, best orientation depends on length.

from memory rods usually are 4:1 up to 10:1 aspect ratio rarely longer,
they break pretty easily. surprisingly the aspect ratio determines more
the 'effective' permeability much more than the basic permeability, like
with a 4:1 anything with more than 100 rel perm makes NO difference.

do you have any way to 'close' the magnetic path just a bit? Tuning makes
a BIG difference! on getting a huge voltage out of it.

I can make some 'guesses' or spend some time to look at it in a bit more
detail over night and get back to you with justifications for why do this
versus do that.

Cross talk you can get some good estimates. If this is for a
'communication' at all; we should discuss that a bit too.

This is an RFQ for a slow speed (~100bps) data link "magnetically",
with ~5mm gap.

I'm just wondering feasibility before sticking my neck out.

...Jim Thompson

Data? That can't miss at 5 mm. I've used similar geometries to
transfer enough power to run a microprocessor-based electric meter
*and* send the data back over the same path, more like 25 mm.

Get an assortment of small unshielded drum-core inductors from Digikey
and measure things. Drums have a nice geometry for axial coupling.
Resonating both ends will help keep the power requirement down. 10 to
50 KHz carrier should be fine. You could get volts at the receive
coil.




--

John Larkin Highland Technology, Inc

jlarkin att highlandtechnology dott com
http://www.highlandtechnology.com

On Sun, 12 Oct 2014 14:40:06 -0700, John Larkin
wrote:

On Sun, 12 Oct 2014 14:14:53 -0700, Jim Thompson
wrote:

On Sun, 12 Oct 2014 14:03:08 -0700, RobertMacy
wrote:

On Sun, 12 Oct 2014 13:25:32 -0700, Jim Thompson
wrote:

On Sun, 12 Oct 2014 13:17:04 -0700, RobertMacy
wrote:

On Sun, 12 Oct 2014 12:45:29 -0700, Jim Thompson
wrote:

I need a SWAG on this, just to see if it's feasible...

Two inductors (solenoids) with Ferrite cores, each ~5mm in diameter
and separated by ~5mm spacing.

What coupling coefficient might I expect?

(Essentially no load on the "receiving" inductor except natural
losses... and I could tune or not.)

...Jim Thompson

5mm rods, how long? what orientation? end to end? side by side?

audio ferrites? low perm ferrites?

I don't know. What would be best? ~100kHz sinusoidal drive

...Jim Thompson

obviously, best orientation depends on length.

from memory rods usually are 4:1 up to 10:1 aspect ratio rarely longer,
they break pretty easily. surprisingly the aspect ratio determines more
the 'effective' permeability much more than the basic permeability, like
with a 4:1 anything with more than 100 rel perm makes NO difference.

do you have any way to 'close' the magnetic path just a bit? Tuning makes
a BIG difference! on getting a huge voltage out of it.

I can make some 'guesses' or spend some time to look at it in a bit more
detail over night and get back to you with justifications for why do this
versus do that.

Cross talk you can get some good estimates. If this is for a
'communication' at all; we should discuss that a bit too.

This is an RFQ for a slow speed (~100bps) data link "magnetically",
with ~5mm gap.

I'm just wondering feasibility before sticking my neck out.

...Jim Thompson

Data? That can't miss at 5 mm. I've used similar geometries to
transfer enough power to run a microprocessor-based electric meter
*and* send the data back over the same path, more like 25 mm.

Get an assortment of small unshielded drum-core inductors from Digikey
and measure things. Drums have a nice geometry for axial coupling.
Resonating both ends will help keep the power requirement down. 10 to
50 KHz carrier should be fine. You could get volts at the receive
coil.

That's pretty much what I expected. But I also have a 5mm "above the
PCB" maximum... do drum/pot cores come that small a diameter?

...Jim Thompson
--
| James E.Thompson | mens |
| Analog Innovations | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| San Tan Valley, AZ 85142 Skype: skypeanalog | |
| Voice480)460-2350 Fax: Available upon request | Brass Rat |
| E-mail Icon at http://www.analog-innovations.com | 1962 |

I love to cook with wine. Sometimes I even put it in the food.

On Sun, 12 Oct 2014 14:49:42 -0700, Jim Thompson
wrote:

On Sun, 12 Oct 2014 14:40:06 -0700, John Larkin
wrote:

On Sun, 12 Oct 2014 14:14:53 -0700, Jim Thompson
wrote:

On Sun, 12 Oct 2014 14:03:08 -0700, RobertMacy
wrote:

On Sun, 12 Oct 2014 13:25:32 -0700, Jim Thompson
wrote:

On Sun, 12 Oct 2014 13:17:04 -0700, RobertMacy
wrote:

On Sun, 12 Oct 2014 12:45:29 -0700, Jim Thompson
wrote:

I need a SWAG on this, just to see if it's feasible...

Two inductors (solenoids) with Ferrite cores, each ~5mm in diameter
and separated by ~5mm spacing.

What coupling coefficient might I expect?

(Essentially no load on the "receiving" inductor except natural
losses... and I could tune or not.)

...Jim Thompson

5mm rods, how long? what orientation? end to end? side by side?

audio ferrites? low perm ferrites?

I don't know. What would be best? ~100kHz sinusoidal drive

...Jim Thompson

obviously, best orientation depends on length.

from memory rods usually are 4:1 up to 10:1 aspect ratio rarely longer,
they break pretty easily. surprisingly the aspect ratio determines more
the 'effective' permeability much more than the basic permeability, like
with a 4:1 anything with more than 100 rel perm makes NO difference.

do you have any way to 'close' the magnetic path just a bit? Tuning makes
a BIG difference! on getting a huge voltage out of it.

I can make some 'guesses' or spend some time to look at it in a bit more
detail over night and get back to you with justifications for why do this
versus do that.

Cross talk you can get some good estimates. If this is for a
'communication' at all; we should discuss that a bit too.

This is an RFQ for a slow speed (~100bps) data link "magnetically",
with ~5mm gap.

I'm just wondering feasibility before sticking my neck out.

...Jim Thompson

Data? That can't miss at 5 mm. I've used similar geometries to
transfer enough power to run a microprocessor-based electric meter
*and* send the data back over the same path, more like 25 mm.

Get an assortment of small unshielded drum-core inductors from Digikey
and measure things. Drums have a nice geometry for axial coupling.
Resonating both ends will help keep the power requirement down. 10 to
50 KHz carrier should be fine. You could get volts at the receive
coil.

That's pretty much what I expected. But I also have a 5mm "above the
PCB" maximum... do drum/pot cores come that small a diameter?

...Jim Thompson

http://www.digikey.com/

http://www.mouser.com/

http://www.coilcraft.com/






--

John Larkin Highland Technology, Inc

jlarkin att highlandtechnology dott com
http://www.highlandtechnology.com

On Sun, 12 Oct 2014 14:14:53 -0700, Jim Thompson
wrote:

On Sun, 12 Oct 2014 14:03:08 -0700, RobertMacy
wrote:

On Sun, 12 Oct 2014 13:25:32 -0700, Jim Thompson
wrote:

On Sun, 12 Oct 2014 13:17:04 -0700, RobertMacy
wrote:

On Sun, 12 Oct 2014 12:45:29 -0700, Jim Thompson
wrote:

I need a SWAG on this, just to see if it's feasible...

Two inductors (solenoids) with Ferrite cores, each ~5mm in diameter
and separated by ~5mm spacing.

What coupling coefficient might I expect?

(Essentially no load on the "receiving" inductor except natural
losses... and I could tune or not.)

...Jim Thompson

5mm rods, how long? what orientation? end to end? side by side?

audio ferrites? low perm ferrites?

I don't know. What would be best? ~100kHz sinusoidal drive

...Jim Thompson

obviously, best orientation depends on length.

from memory rods usually are 4:1 up to 10:1 aspect ratio rarely longer,
they break pretty easily. surprisingly the aspect ratio determines more
the 'effective' permeability much more than the basic permeability, like
with a 4:1 anything with more than 100 rel perm makes NO difference.

do you have any way to 'close' the magnetic path just a bit? Tuning
makes
a BIG difference! on getting a huge voltage out of it.

I can make some 'guesses' or spend some time to look at it in a bit more
detail over night and get back to you with justifications for why do
this
versus do that.

Cross talk you can get some good estimates. If this is for a
'communication' at all; we should discuss that a bit too.

This is an RFQ for a slow speed (~100bps) data link "magnetically",
with ~5mm gap.

I'm just wondering feasibility before sticking my neck out.

...Jim Thompson

Full-duplex? piece of cake! I've done that using air core PCB coils [no
winding necessary] and operate over a distance of 8 inches using less than
3.3Vdc, 5mA per TxRx pair. Also, no tuning required, no 'touchy' high
tolerance analog parts. PLUS, not even catch the attention of FCC, operate
in a true don't care band.

100bps! I'ved designed systems that communicate MILES, through salt water
to do that!

no 5mm, 100bps full-duplex, piece of cake.

Big hint: communication between two entities should NEVER be treated like
a radio transmitter/radio receiver pair. leave THAT for the broadcast
industry where ONE talks to many. Rather THINK SYSTEM! where BOTH must
communicate hand in hand, not simply throwing information out there hoping
the other stumbles over it. Thinking system will get reliable cheap
communication that even instantly flags you as the link starts to weaken!

Sorry, have to get offline for a bit, painting here.

On Sun, 12 Oct 2014 14:59:33 -0700, John Larkin
wrote:

On Sun, 12 Oct 2014 14:49:42 -0700, Jim Thompson
wrote:

On Sun, 12 Oct 2014 14:40:06 -0700, John Larkin
wrote:

On Sun, 12 Oct 2014 14:14:53 -0700, Jim Thompson
wrote:

On Sun, 12 Oct 2014 14:03:08 -0700, RobertMacy
wrote:

On Sun, 12 Oct 2014 13:25:32 -0700, Jim Thompson
wrote:

On Sun, 12 Oct 2014 13:17:04 -0700, RobertMacy
wrote:

On Sun, 12 Oct 2014 12:45:29 -0700, Jim Thompson
wrote:

I need a SWAG on this, just to see if it's feasible...

Two inductors (solenoids) with Ferrite cores, each ~5mm in diameter
and separated by ~5mm spacing.

What coupling coefficient might I expect?

(Essentially no load on the "receiving" inductor except natural
losses... and I could tune or not.)

...Jim Thompson

5mm rods, how long? what orientation? end to end? side by side?

audio ferrites? low perm ferrites?

I don't know. What would be best? ~100kHz sinusoidal drive

...Jim Thompson

obviously, best orientation depends on length.

from memory rods usually are 4:1 up to 10:1 aspect ratio rarely longer,
they break pretty easily. surprisingly the aspect ratio determines more
the 'effective' permeability much more than the basic permeability, like
with a 4:1 anything with more than 100 rel perm makes NO difference.

do you have any way to 'close' the magnetic path just a bit? Tuning makes
a BIG difference! on getting a huge voltage out of it.

I can make some 'guesses' or spend some time to look at it in a bit more
detail over night and get back to you with justifications for why do this
versus do that.

Cross talk you can get some good estimates. If this is for a
'communication' at all; we should discuss that a bit too.

This is an RFQ for a slow speed (~100bps) data link "magnetically",
with ~5mm gap.

I'm just wondering feasibility before sticking my neck out.

...Jim Thompson

Data? That can't miss at 5 mm. I've used similar geometries to
transfer enough power to run a microprocessor-based electric meter
*and* send the data back over the same path, more like 25 mm.

Get an assortment of small unshielded drum-core inductors from Digikey
and measure things. Drums have a nice geometry for axial coupling.
Resonating both ends will help keep the power requirement down. 10 to
50 KHz carrier should be fine. You could get volts at the receive
coil.

That's pretty much what I expected. But I also have a 5mm "above the
PCB" maximum... do drum/pot cores come that small a diameter?

...Jim Thompson

http://www.digikey.com/

http://www.mouser.com/

http://www.coilcraft.com/

Thanks!

...Jim Thompson
--
| James E.Thompson | mens |
| Analog Innovations | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| San Tan Valley, AZ 85142 Skype: skypeanalog | |
| Voice480)460-2350 Fax: Available upon request | Brass Rat |
| E-mail Icon at http://www.analog-innovations.com | 1962 |

I love to cook with wine. Sometimes I even put it in the food.

On Sun, 12 Oct 2014 14:59:51 -0700, RobertMacy
wrote:

On Sun, 12 Oct 2014 14:14:53 -0700, Jim Thompson
wrote:

On Sun, 12 Oct 2014 14:03:08 -0700, RobertMacy
wrote:

On Sun, 12 Oct 2014 13:25:32 -0700, Jim Thompson
wrote:

On Sun, 12 Oct 2014 13:17:04 -0700, RobertMacy
wrote:

On Sun, 12 Oct 2014 12:45:29 -0700, Jim Thompson
wrote:

I need a SWAG on this, just to see if it's feasible...

Two inductors (solenoids) with Ferrite cores, each ~5mm in diameter
and separated by ~5mm spacing.

What coupling coefficient might I expect?

(Essentially no load on the "receiving" inductor except natural
losses... and I could tune or not.)

...Jim Thompson

5mm rods, how long? what orientation? end to end? side by side?

audio ferrites? low perm ferrites?

I don't know. What would be best? ~100kHz sinusoidal drive

...Jim Thompson

obviously, best orientation depends on length.

from memory rods usually are 4:1 up to 10:1 aspect ratio rarely longer,
they break pretty easily. surprisingly the aspect ratio determines more
the 'effective' permeability much more than the basic permeability, like
with a 4:1 anything with more than 100 rel perm makes NO difference.

do you have any way to 'close' the magnetic path just a bit? Tuning
makes
a BIG difference! on getting a huge voltage out of it.

I can make some 'guesses' or spend some time to look at it in a bit more
detail over night and get back to you with justifications for why do
this
versus do that.

Cross talk you can get some good estimates. If this is for a
'communication' at all; we should discuss that a bit too.

This is an RFQ for a slow speed (~100bps) data link "magnetically",
with ~5mm gap.

I'm just wondering feasibility before sticking my neck out.

...Jim Thompson

Full-duplex? piece of cake! I've done that using air core PCB coils [no
winding necessary] and operate over a distance of 8 inches using less than
3.3Vdc, 5mA per TxRx pair. Also, no tuning required, no 'touchy' high
tolerance analog parts. PLUS, not even catch the attention of FCC, operate
in a true don't care band.

100bps! I'ved designed systems that communicate MILES, through salt water
to do that!

no 5mm, 100bps full-duplex, piece of cake.

Big hint: communication between two entities should NEVER be treated like
a radio transmitter/radio receiver pair. leave THAT for the broadcast
industry where ONE talks to many. Rather THINK SYSTEM! where BOTH must
communicate hand in hand, not simply throwing information out there hoping
the other stumbles over it. Thinking system will get reliable cheap
communication that even instantly flags you as the link starts to weaken!

Sorry, have to get offline for a bit, painting here.

Me, too! IKEA bookcases ;-)

...Jim Thompson
--
| James E.Thompson | mens |
| Analog Innovations | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| San Tan Valley, AZ 85142 Skype: skypeanalog | |
| Voice480)460-2350 Fax: Available upon request | Brass Rat |
| E-mail Icon at http://www.analog-innovations.com | 1962 |

I love to cook with wine. Sometimes I even put it in the food.

On Sun, 12 Oct 2014 15:00:19 -0700, Jim Thompson
wrote:

On Sun, 12 Oct 2014 14:59:33 -0700, John Larkin
wrote:

On Sun, 12 Oct 2014 14:49:42 -0700, Jim Thompson
wrote:

On Sun, 12 Oct 2014 14:40:06 -0700, John Larkin
wrote:

On Sun, 12 Oct 2014 14:14:53 -0700, Jim Thompson
wrote:

On Sun, 12 Oct 2014 14:03:08 -0700, RobertMacy
wrote:

On Sun, 12 Oct 2014 13:25:32 -0700, Jim Thompson
wrote:

On Sun, 12 Oct 2014 13:17:04 -0700, RobertMacy
wrote:

On Sun, 12 Oct 2014 12:45:29 -0700, Jim Thompson
wrote:

I need a SWAG on this, just to see if it's feasible...

Two inductors (solenoids) with Ferrite cores, each ~5mm in diameter
and separated by ~5mm spacing.

What coupling coefficient might I expect?

(Essentially no load on the "receiving" inductor except natural
losses... and I could tune or not.)

...Jim Thompson

5mm rods, how long? what orientation? end to end? side by side?

audio ferrites? low perm ferrites?

I don't know. What would be best? ~100kHz sinusoidal drive

...Jim Thompson

obviously, best orientation depends on length.

from memory rods usually are 4:1 up to 10:1 aspect ratio rarely longer,
they break pretty easily. surprisingly the aspect ratio determines more
the 'effective' permeability much more than the basic permeability, like
with a 4:1 anything with more than 100 rel perm makes NO difference.

do you have any way to 'close' the magnetic path just a bit? Tuning makes
a BIG difference! on getting a huge voltage out of it.

I can make some 'guesses' or spend some time to look at it in a bit more
detail over night and get back to you with justifications for why do this
versus do that.

Cross talk you can get some good estimates. If this is for a
'communication' at all; we should discuss that a bit too.

This is an RFQ for a slow speed (~100bps) data link "magnetically",
with ~5mm gap.

I'm just wondering feasibility before sticking my neck out.

...Jim Thompson

Data? That can't miss at 5 mm. I've used similar geometries to
transfer enough power to run a microprocessor-based electric meter
*and* send the data back over the same path, more like 25 mm.

Get an assortment of small unshielded drum-core inductors from Digikey
and measure things. Drums have a nice geometry for axial coupling.
Resonating both ends will help keep the power requirement down. 10 to
50 KHz carrier should be fine. You could get volts at the receive
coil.

That's pretty much what I expected. But I also have a 5mm "above the
PCB" maximum... do drum/pot cores come that small a diameter?

...Jim Thompson

http://www.digikey.com/

http://www.mouser.com/

http://www.coilcraft.com/

Thanks!

...Jim Thompson


http://www.coilcraft.com/pdfs/powersel_8.5x11.pdf

Take a look at the unshielded ones, ME2200 or DO1608C. Coilcraft is
great for sampling.


--

John Larkin Highland Technology, Inc

jlarkin att highlandtechnology dott com
http://www.highlandtechnology.com

On Sun, 12 Oct 2014 14:49:42 -0700, Jim Thompson
wrote:

...snip...!!!!!
That's pretty much what I expected. But I also have a 5mm "above the
PCB" maximum... do drum/pot cores come that small a diameter?

...Jim Thompson

Stop it! you're going to optimize a weak design following this path. If
you want to avoid FCC scrutiny stay below 10KHz. Don't even use ferrites,
no real need. You aren't transferring energy, you're transferring
'information', where almost NO power still will tell you stuff.

ARRRGGG!

I've got a system in mind that will cost less than $1 each in volumes of
100, and if you have some left over uController power, like inside TI's
MSP430, the rest is FREE! jeeesh!

ferrites?! barbaric! plus weight, mounting, wrapping, vibration etc etc
..... stay away from antique concepts, PLEASE!

On Sun, 12 Oct 2014 15:01:19 -0700, Jim Thompson
wrote:

...snip...

Me, too! IKEA bookcases ;-)

...Jim Thompson

See reply to what3rd who did an excellent 'rule-of-thumb' estimate.

I was VERY surprised to see approximately 0.1 coupling!

If you're stuck on using this approach, and need a model; I've already got
the .asc running for various positions. However, it's easy to do a curve
fit and produce k vs position, too.

Is this for isolation? high voltage separation? Have you thought of using
those cheap LED 'handheld remote controllers' They transmit quite a
distance, cost nothing and run on nothing, ...well almost. but you get to
piggy back on VOLUME production costs. Bunch of chipsets out there.

On Mon, 13 Oct 2014 07:25:04 -0700, RobertMacy
wrote:

On Sun, 12 Oct 2014 15:01:19 -0700, Jim Thompson
wrote:

...snip...

Me, too! IKEA bookcases ;-)

...Jim Thompson

See reply to what3rd who did an excellent 'rule-of-thumb' estimate.

I was VERY surprised to see approximately 0.1 coupling!

If you're stuck on using this approach, and need a model; I've already got
the .asc running for various positions. However, it's easy to do a curve
fit and produce k vs position, too.

Is this for isolation? high voltage separation? Have you thought of using
those cheap LED 'handheld remote controllers' They transmit quite a
distance, cost nothing and run on nothing, ...well almost. but you get to
piggy back on VOLUME production costs. Bunch of chipsets out there.

This is one of those "I wouldn't do it this way", but I'm looking into
it at the insistence of the client.

...Jim Thompson
--
| James E.Thompson | mens |
| Analog Innovations | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| San Tan Valley, AZ 85142 Skype: skypeanalog | |
| Voice480)460-2350 Fax: Available upon request | Brass Rat |
| E-mail Icon at http://www.analog-innovations.com | 1962 |

I love to cook with wine. Sometimes I even put it in the food.

On Mon, 13 Oct 2014 08:38:23 -0700, Jim Thompson
wrote:

...snip....

This is one of those "I wouldn't do it this way", but I'm looking into
it at the insistence of the client.

...Jim Thompson

whew! but still, will have your name on it when finished.

However, I just confirmed that using a rod that is 5mm diameter by 1cm
long and the permeability changes from 2000 down to 1000 you only get
about 0.3% change in inductance. [remember I said a function of aspect
ratio?] which means *if* you tune the inductor, it will stay pretty much
in tune. At least for a Q of 100 and that should be good enough for
peaking the signal AND getting 1kHz through on a 100kHz carrier. [more
possible but allow some sloppiness] and 1kHz sidebands means at least
2kb/s. and that means at least 200+ Full Duplex so you're done.

The answer is yes it can be done that way.

On Mon, 13 Oct 2014 12:57:21 -0700, RobertMacy
wrote:

On Mon, 13 Oct 2014 08:38:23 -0700, Jim Thompson
wrote:

...snip....

This is one of those "I wouldn't do it this way", but I'm looking into
it at the insistence of the client.

...Jim Thompson

whew! but still, will have your name on it when finished.

That's OK. If I design it... it _will_ work :-}


However, I just confirmed that using a rod that is 5mm diameter by 1cm
long and the permeability changes from 2000 down to 1000 you only get
about 0.3% change in inductance. [remember I said a function of aspect
ratio?] which means *if* you tune the inductor, it will stay pretty much
in tune. At least for a Q of 100 and that should be good enough for
peaking the signal AND getting 1kHz through on a 100kHz carrier. [more
possible but allow some sloppiness] and 1kHz sidebands means at least
2kb/s. and that means at least 200+ Full Duplex so you're done.

The answer is yes it can be done that way.

...Jim Thompson
--
| James E.Thompson | mens |
| Analog Innovations | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| San Tan Valley, AZ 85142 Skype: skypeanalog | |
| Voice480)460-2350 Fax: Available upon request | Brass Rat |
| E-mail Icon at http://www.analog-innovations.com | 1962 |

I love to cook with wine. Sometimes I even put it in the food.

On Mon, 13 Oct 2014 13:05:47 -0700, Jim Thompson
wrote:

...snip....

That's OK. If I design it... it _will_ work :-}

Wasn't questioning that aspect, just the "why did he do it this way?"
aspect. and NOT even use vacuum tubes!

On Mon, 13 Oct 2014 13:13:23 -0700, RobertMacy
wrote:

On Mon, 13 Oct 2014 13:05:47 -0700, Jim Thompson
wrote:

...snip....

That's OK. If I design it... it _will_ work :-}

Wasn't questioning that aspect, just the "why did he do it this way?"
aspect. and NOT even use vacuum tubes!

Doing some housekeeping of my PSpice symbol library I noted that, in
the past, I created symbols for triode, tetrode, and two pentode
symbols, dependent on number of grid pins that come out, so I'm ready
:-}

...Jim Thompson
--
| James E.Thompson | mens |
| Analog Innovations | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| San Tan Valley, AZ 85142 Skype: skypeanalog | |
| Voice480)460-2350 Fax: Available upon request | Brass Rat |
| E-mail Icon at http://www.analog-innovations.com | 1962 |

I love to cook with wine. Sometimes I even put it in the food.

Jim Thompson wrote:

On Mon, 13 Oct 2014 13:13:23 -0700, RobertMacy
wrote:

On Mon, 13 Oct 2014 13:05:47 -0700, Jim Thompson
wrote:

...snip....

That's OK. If I design it... it _will_ work :-}

Wasn't questioning that aspect, just the "why did he do it this way?"
aspect. and NOT even use vacuum tubes!

Doing some housekeeping of my PSpice symbol library I noted that, in
the past, I created symbols for triode, tetrode, and two pentode
symbols, dependent on number of grid pins that come out, so I'm ready
:-}


How about Interociter parts?



--
Anyone wanting to run for any political office in the US should have to
have a DD214, and a honorable discharge.

On Mon, 13 Oct 2014 13:20:15 -0700, Jim Thompson
wrote:

On Mon, 13 Oct 2014 13:13:23 -0700, RobertMacy
wrote:

On Mon, 13 Oct 2014 13:05:47 -0700, Jim Thompson
wrote:

...snip....

That's OK. If I design it... it _will_ work :-}

Wasn't questioning that aspect, just the "why did he do it this way?"
aspect. and NOT even use vacuum tubes!

Doing some housekeeping of my PSpice symbol library I noted that, in
the past, I created symbols for triode, tetrode, and two pentode
symbols, dependent on number of grid pins that come out, so I'm ready
:-}

...Jim Thompson


I've done tube designs, back when they were the only devices that could
handle 10-20kV

I finally successfully replaced in one location, the high voltage drivers.
Using [Delco?] 1200Vceo NPN transistors and a step up transformer
....inside the loop to remove the characteristics of the transformer. All
to get accurate 5kVpp audio sawtooth waveforms [better than 0.1%
linearity] not bad when you consider those !@#$#! resistors have voltage
coefficients that're out of sight!

On Sun, 12 Oct 2014 14:14:53 -0700, Jim Thompson
wrote:

On Sun, 12 Oct 2014 14:03:08 -0700, RobertMacy
wrote:

On Sun, 12 Oct 2014 13:25:32 -0700, Jim Thompson
wrote:

On Sun, 12 Oct 2014 13:17:04 -0700, RobertMacy
wrote:

On Sun, 12 Oct 2014 12:45:29 -0700, Jim Thompson
wrote:

I need a SWAG on this, just to see if it's feasible...

Two inductors (solenoids) with Ferrite cores, each ~5mm in diameter
and separated by ~5mm spacing.

What coupling coefficient might I expect?

(Essentially no load on the "receiving" inductor except natural
losses... and I could tune or not.)

...Jim Thompson

5mm rods, how long? what orientation? end to end? side by side?

audio ferrites? low perm ferrites?

I don't know. What would be best? ~100kHz sinusoidal drive

...Jim Thompson

obviously, best orientation depends on length.

from memory rods usually are 4:1 up to 10:1 aspect ratio rarely longer,
they break pretty easily. surprisingly the aspect ratio determines more
the 'effective' permeability much more than the basic permeability, like
with a 4:1 anything with more than 100 rel perm makes NO difference.

do you have any way to 'close' the magnetic path just a bit? Tuning makes
a BIG difference! on getting a huge voltage out of it.

I can make some 'guesses' or spend some time to look at it in a bit more
detail over night and get back to you with justifications for why do this
versus do that.

Cross talk you can get some good estimates. If this is for a
'communication' at all; we should discuss that a bit too.

This is an RFQ for a slow speed (~100bps) data link "magnetically",
with ~5mm gap.

I'm just wondering feasibility before sticking my neck out.

...Jim Thompson


OK fine. Galvanically isolated to very many kilovolts? Why do they want
this?

?-)

On Wed, 15 Oct 2014 00:20:13 -0700, josephkk
wrote:

On Sun, 12 Oct 2014 14:14:53 -0700, Jim Thompson
wrote:

On Sun, 12 Oct 2014 14:03:08 -0700, RobertMacy
wrote:

On Sun, 12 Oct 2014 13:25:32 -0700, Jim Thompson
wrote:

On Sun, 12 Oct 2014 13:17:04 -0700, RobertMacy
wrote:

On Sun, 12 Oct 2014 12:45:29 -0700, Jim Thompson
wrote:

I need a SWAG on this, just to see if it's feasible...

Two inductors (solenoids) with Ferrite cores, each ~5mm in diameter
and separated by ~5mm spacing.

What coupling coefficient might I expect?

(Essentially no load on the "receiving" inductor except natural
losses... and I could tune or not.)

...Jim Thompson

5mm rods, how long? what orientation? end to end? side by side?

audio ferrites? low perm ferrites?

I don't know. What would be best? ~100kHz sinusoidal drive

...Jim Thompson

obviously, best orientation depends on length.

from memory rods usually are 4:1 up to 10:1 aspect ratio rarely longer,
they break pretty easily. surprisingly the aspect ratio determines more
the 'effective' permeability much more than the basic permeability, like
with a 4:1 anything with more than 100 rel perm makes NO difference.

do you have any way to 'close' the magnetic path just a bit? Tuning makes
a BIG difference! on getting a huge voltage out of it.

I can make some 'guesses' or spend some time to look at it in a bit more
detail over night and get back to you with justifications for why do this
versus do that.

Cross talk you can get some good estimates. If this is for a
'communication' at all; we should discuss that a bit too.

This is an RFQ for a slow speed (~100bps) data link "magnetically",
with ~5mm gap.

I'm just wondering feasibility before sticking my neck out.

...Jim Thompson


OK fine. Galvanically isolated to very many kilovolts? Why do they want
this?

?-)


5mm-10mm spacing is all I know.

...Jim Thompson
--
| James E.Thompson | mens |
| Analog Innovations | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| San Tan Valley, AZ 85142 Skype: skypeanalog | |
| Voice480)460-2350 Fax: Available upon request | Brass Rat |
| E-mail Icon at http://www.analog-innovations.com | 1962 |

I love to cook with wine. Sometimes I even put it in the food.

josephkk wrote:
On Sun, 12 Oct 2014 14:14:53 -0700, Jim Thompson
wrote:

On Sun, 12 Oct 2014 14:03:08 -0700, RobertMacy
wrote:

On Sun, 12 Oct 2014 13:25:32 -0700, Jim Thompson
wrote:

On Sun, 12 Oct 2014 13:17:04 -0700, RobertMacy
wrote:

On Sun, 12 Oct 2014 12:45:29 -0700, Jim Thompson
wrote:

I need a SWAG on this, just to see if it's feasible...

Two inductors (solenoids) with Ferrite cores, each ~5mm in diameter
and separated by ~5mm spacing.

What coupling coefficient might I expect?

(Essentially no load on the "receiving" inductor except natural
losses... and I could tune or not.)

...Jim Thompson

5mm rods, how long? what orientation? end to end? side by side?

audio ferrites? low perm ferrites?

I don't know. What would be best? ~100kHz sinusoidal drive

...Jim Thompson

obviously, best orientation depends on length.

from memory rods usually are 4:1 up to 10:1 aspect ratio rarely longer,
they break pretty easily. surprisingly the aspect ratio determines more
the 'effective' permeability much more than the basic permeability, like
with a 4:1 anything with more than 100 rel perm makes NO difference.

do you have any way to 'close' the magnetic path just a bit? Tuning makes
a BIG difference! on getting a huge voltage out of it.

I can make some 'guesses' or spend some time to look at it in a bit more
detail over night and get back to you with justifications for why do this
versus do that.

Cross talk you can get some good estimates. If this is for a
'communication' at all; we should discuss that a bit too.

This is an RFQ for a slow speed (~100bps) data link "magnetically",
with ~5mm gap.

I'm just wondering feasibility before sticking my neck out.

...Jim Thompson


OK fine. Galvanically isolated to very many kilovolts? Why do they want
this?

?-)

Doesn't TI make a chip good for the low KV region?

On Wed, 15 Oct 2014 09:55:23 -0700, Robert Baer
wrote:

josephkk wrote:
On Sun, 12 Oct 2014 14:14:53 -0700, Jim Thompson
wrote:

On Sun, 12 Oct 2014 14:03:08 -0700, RobertMacy
wrote:

On Sun, 12 Oct 2014 13:25:32 -0700, Jim Thompson
wrote:

On Sun, 12 Oct 2014 13:17:04 -0700, RobertMacy
wrote:

On Sun, 12 Oct 2014 12:45:29 -0700, Jim Thompson
wrote:

I need a SWAG on this, just to see if it's feasible...

Two inductors (solenoids) with Ferrite cores, each ~5mm in diameter
and separated by ~5mm spacing.

What coupling coefficient might I expect?

(Essentially no load on the "receiving" inductor except natural
losses... and I could tune or not.)

...Jim Thompson

5mm rods, how long? what orientation? end to end? side by side?

audio ferrites? low perm ferrites?

I don't know. What would be best? ~100kHz sinusoidal drive

...Jim Thompson

obviously, best orientation depends on length.

from memory rods usually are 4:1 up to 10:1 aspect ratio rarely longer,
they break pretty easily. surprisingly the aspect ratio determines more
the 'effective' permeability much more than the basic permeability, like
with a 4:1 anything with more than 100 rel perm makes NO difference.

do you have any way to 'close' the magnetic path just a bit? Tuning makes
a BIG difference! on getting a huge voltage out of it.

I can make some 'guesses' or spend some time to look at it in a bit more
detail over night and get back to you with justifications for why do this
versus do that.

Cross talk you can get some good estimates. If this is for a
'communication' at all; we should discuss that a bit too.

This is an RFQ for a slow speed (~100bps) data link "magnetically",
with ~5mm gap.

I'm just wondering feasibility before sticking my neck out.

...Jim Thompson


OK fine. Galvanically isolated to very many kilovolts? Why do they want
this?

?-)

Doesn't TI make a chip good for the low KV region?

Two separate boards, not just an isolation barrier.

...Jim Thompson
--
| James E.Thompson | mens |
| Analog Innovations | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| San Tan Valley, AZ 85142 Skype: skypeanalog | |
| Voice480)460-2350 Fax: Available upon request | Brass Rat |
| E-mail Icon at http://www.analog-innovations.com | 1962 |

I love to cook with wine. Sometimes I even put it in the food.

Jim Thompson wrote:
On Wed, 15 Oct 2014 09:55:23 -0700, Robert Baer
wrote:

josephkk wrote:
On Sun, 12 Oct 2014 14:14:53 -0700, Jim Thompson
wrote:

On Sun, 12 Oct 2014 14:03:08 -0700, RobertMacy
wrote:

On Sun, 12 Oct 2014 13:25:32 -0700, Jim Thompson
wrote:

On Sun, 12 Oct 2014 13:17:04 -0700, RobertMacy
wrote:

On Sun, 12 Oct 2014 12:45:29 -0700, Jim Thompson
wrote:

I need a SWAG on this, just to see if it's feasible...

Two inductors (solenoids) with Ferrite cores, each ~5mm in diameter
and separated by ~5mm spacing.

What coupling coefficient might I expect?

(Essentially no load on the "receiving" inductor except natural
losses... and I could tune or not.)

...Jim Thompson

5mm rods, how long? what orientation? end to end? side by side?

audio ferrites? low perm ferrites?

I don't know. What would be best? ~100kHz sinusoidal drive

...Jim Thompson

obviously, best orientation depends on length.

from memory rods usually are 4:1 up to 10:1 aspect ratio rarely longer,
they break pretty easily. surprisingly the aspect ratio determines more
the 'effective' permeability much more than the basic permeability, like
with a 4:1 anything with more than 100 rel perm makes NO difference.

do you have any way to 'close' the magnetic path just a bit? Tuning makes
a BIG difference! on getting a huge voltage out of it.

I can make some 'guesses' or spend some time to look at it in a bit more
detail over night and get back to you with justifications for why do this
versus do that.

Cross talk you can get some good estimates. If this is for a
'communication' at all; we should discuss that a bit too.

This is an RFQ for a slow speed (~100bps) data link "magnetically",
with ~5mm gap.

I'm just wondering feasibility before sticking my neck out.

...Jim Thompson


OK fine. Galvanically isolated to very many kilovolts? Why do they want
this?

?-)

Doesn't TI make a chip good for the low KV region?

Two separate boards, not just an isolation barrier.

...Jim Thompson
Maybe use a toroid, Teflon winding on the HV side, use left qtr for
pri, right qtr for sec, dip in Glyptal?

On Sun, 12 Oct 2014 12:45:29 -0700, Jim Thompson
wrote:

I need a SWAG on this, just to see if it's feasible...

Two inductors (solenoids) with Ferrite cores, each ~5mm in diameter
and separated by ~5mm spacing.

What coupling coefficient might I expect?

(Essentially no load on the "receiving" inductor except natural
losses... and I could tune or not.)

...Jim Thompson

Customer built a PCB and is getting good data coupling out to 2"
spacing.

Both ends are tuned with Q~10, so I'm going to cut it back a bit, I
fear cross-talk issues when he implements multi-channels.

...Jim Thompson
--
| James E.Thompson | mens |
| Analog Innovations | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| San Tan Valley, AZ 85142 Skype: skypeanalog | |
| Voice480)460-2350 Fax: Available upon request | Brass Rat |
| E-mail Icon at http://www.analog-innovations.com | 1962 |

I love to cook with wine. Sometimes I even put it in the food.

On Thu, 27 Nov 2014 11:20:38 -0700, Jim Thompson
wrote:

On Sun, 12 Oct 2014 12:45:29 -0700, Jim Thompson
wrote:

I need a SWAG on this, just to see if it's feasible...

Two inductors (solenoids) with Ferrite cores, each ~5mm in diameter
and separated by ~5mm spacing.

What coupling coefficient might I expect?

(Essentially no load on the "receiving" inductor except natural
losses... and I could tune or not.)

...Jim Thompson

Customer built a PCB and is getting good data coupling out to 2"
spacing.

Both ends are tuned with Q~10, so I'm going to cut it back a bit, I
fear cross-talk issues when he implements multi-channels.

...Jim Thompson

Can he put alternate channels on the opposite side of the board?
Or maybe a EMI shielding enclosure, might cause a change in the
inductance of the coil a bit.

Cheers

On Thu, 27 Nov 2014 18:14:07 -0500, Martin Riddle
wrote:

On Thu, 27 Nov 2014 11:20:38 -0700, Jim Thompson
wrote:

On Sun, 12 Oct 2014 12:45:29 -0700, Jim Thompson
wrote:

I need a SWAG on this, just to see if it's feasible...

Two inductors (solenoids) with Ferrite cores, each ~5mm in diameter
and separated by ~5mm spacing.

What coupling coefficient might I expect?

(Essentially no load on the "receiving" inductor except natural
losses... and I could tune or not.)

...Jim Thompson

Customer built a PCB and is getting good data coupling out to 2"
spacing.

Both ends are tuned with Q~10, so I'm going to cut it back a bit, I
fear cross-talk issues when he implements multi-channels.

...Jim Thompson

Can he put alternate channels on the opposite side of the board?
Or maybe a EMI shielding enclosure, might cause a change in the
inductance of the coil a bit.

Cheers

Customer has 1' PCB panels... Single inputs on N and W sides, outputs
on E and S sides.

...Jim Thompson
--
| James E.Thompson | mens |
| Analog Innovations | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| San Tan Valley, AZ 85142 Skype: skypeanalog | |
| Voice480)460-2350 Fax: Available upon request | Brass Rat |
| E-mail Icon at http://www.analog-innovations.com | 1962 |

I love to cook with wine. Sometimes I even put it in the food.

Jim Thompson wrote:
On Thu, 27 Nov 2014 18:14:07 -0500, Martin Riddle
wrote:

On Thu, 27 Nov 2014 11:20:38 -0700, Jim Thompson
wrote:

On Sun, 12 Oct 2014 12:45:29 -0700, Jim Thompson
wrote:

I need a SWAG on this, just to see if it's feasible...

Two inductors (solenoids) with Ferrite cores, each ~5mm in diameter
and separated by ~5mm spacing.

What coupling coefficient might I expect?

(Essentially no load on the "receiving" inductor except natural
losses... and I could tune or not.)

...Jim Thompson

Customer built a PCB and is getting good data coupling out to 2"
spacing.

Both ends are tuned with Q~10, so I'm going to cut it back a bit, I
fear cross-talk issues when he implements multi-channels.

...Jim Thompson

Can he put alternate channels on the opposite side of the board?
Or maybe a EMI shielding enclosure, might cause a change in the
inductance of the coil a bit.

Cheers

Customer has 1' PCB panels... Single inputs on N and W sides, outputs
on E and S sides.

...Jim Thompson
Sheet of mu metal placed at 45 degrees?
Stuff is rather good even at 60Hz and would get better as frequency
goes up.
Tie sheet to system ground plane, natch.

On Thu, 27 Nov 2014 16:43:17 -0800, Robert Baer
wrote:

Jim Thompson wrote:
On Thu, 27 Nov 2014 18:14:07 -0500, Martin Riddle
wrote:

On Thu, 27 Nov 2014 11:20:38 -0700, Jim Thompson
wrote:

On Sun, 12 Oct 2014 12:45:29 -0700, Jim Thompson
wrote:

I need a SWAG on this, just to see if it's feasible...

Two inductors (solenoids) with Ferrite cores, each ~5mm in diameter
and separated by ~5mm spacing.

What coupling coefficient might I expect?

(Essentially no load on the "receiving" inductor except natural
losses... and I could tune or not.)

...Jim Thompson

Customer built a PCB and is getting good data coupling out to 2"
spacing.

Both ends are tuned with Q~10, so I'm going to cut it back a bit, I
fear cross-talk issues when he implements multi-channels.

...Jim Thompson

Can he put alternate channels on the opposite side of the board?
Or maybe a EMI shielding enclosure, might cause a change in the
inductance of the coil a bit.

Cheers

Customer has 1' PCB panels... Single inputs on N and W sides, outputs
on E and S sides.

...Jim Thompson
Sheet of mu metal placed at 45 degrees?
Stuff is rather good even at 60Hz and would get better as frequency
goes up.
Tie sheet to system ground plane, natch.

I've seen FM radios with a small single wall shield next to inductors
to break up the field. As long as the inductors are mounted 90deg from
one another coupling is at a minimum. I vaguely recall coils are
needed, so toroids are out of the question.


Cheers

On Thu, 27 Nov 2014 20:11:58 -0500, Martin Riddle
wrote:

On Thu, 27 Nov 2014 16:43:17 -0800, Robert Baer
wrote:

Jim Thompson wrote:
On Thu, 27 Nov 2014 18:14:07 -0500, Martin Riddle
wrote:

On Thu, 27 Nov 2014 11:20:38 -0700, Jim Thompson
wrote:

On Sun, 12 Oct 2014 12:45:29 -0700, Jim Thompson
wrote:

I need a SWAG on this, just to see if it's feasible...

Two inductors (solenoids) with Ferrite cores, each ~5mm in diameter
and separated by ~5mm spacing.

What coupling coefficient might I expect?

(Essentially no load on the "receiving" inductor except natural
losses... and I could tune or not.)

...Jim Thompson

Customer built a PCB and is getting good data coupling out to 2"
spacing.

Both ends are tuned with Q~10, so I'm going to cut it back a bit, I
fear cross-talk issues when he implements multi-channels.

...Jim Thompson

Can he put alternate channels on the opposite side of the board?
Or maybe a EMI shielding enclosure, might cause a change in the
inductance of the coil a bit.

Cheers

Customer has 1' PCB panels... Single inputs on N and W sides, outputs
on E and S sides.

...Jim Thompson
Sheet of mu metal placed at 45 degrees?
Stuff is rather good even at 60Hz and would get better as frequency
goes up.
Tie sheet to system ground plane, natch.

I've seen FM radios with a small single wall shield next to inductors
to break up the field. As long as the inductors are mounted 90deg from
one another coupling is at a minimum. I vaguely recall coils are
needed, so toroids are out of the question.


Cheers

http://www.analog-innovations.com/SED/MagneticDataCoupling.mov

...Jim Thompson
--
| James E.Thompson | mens |
| Analog Innovations | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| San Tan Valley, AZ 85142 Skype: skypeanalog | |
| Voice480)460-2350 Fax: Available upon request | Brass Rat |
| E-mail Icon at http://www.analog-innovations.com | 1962 |

I love to cook with wine. Sometimes I even put it in the food.

Martin Riddle wrote:
On Thu, 27 Nov 2014 16:43:17 -0800, Robert Baer
wrote:

Jim Thompson wrote:
On Thu, 27 Nov 2014 18:14:07 -0500, Martin Riddle
wrote:

On Thu, 27 Nov 2014 11:20:38 -0700, Jim Thompson
wrote:

On Sun, 12 Oct 2014 12:45:29 -0700, Jim Thompson
wrote:

I need a SWAG on this, just to see if it's feasible...

Two inductors (solenoids) with Ferrite cores, each ~5mm in diameter
and separated by ~5mm spacing.

What coupling coefficient might I expect?

(Essentially no load on the "receiving" inductor except natural
losses... and I could tune or not.)

...Jim Thompson

Customer built a PCB and is getting good data coupling out to 2"
spacing.

Both ends are tuned with Q~10, so I'm going to cut it back a bit, I
fear cross-talk issues when he implements multi-channels.

...Jim Thompson

Can he put alternate channels on the opposite side of the board?
Or maybe a EMI shielding enclosure, might cause a change in the
inductance of the coil a bit.

Cheers

Customer has 1' PCB panels... Single inputs on N and W sides, outputs
on E and S sides.

...Jim Thompson
Sheet of mu metal placed at 45 degrees?
Stuff is rather good even at 60Hz and would get better as frequency
goes up.
Tie sheet to system ground plane, natch.

I've seen FM radios with a small single wall shield next to inductors
to break up the field. As long as the inductors are mounted 90deg from
one another coupling is at a minimum. I vaguely recall coils are
needed, so toroids are out of the question.


Cheers
Check; from the description of input , output coils,it would seem
that parallel orientation would be the case..

out / *
* -- mu metal shield
channel one *
*
in / * / in
*
* channel 2
* out /

I think i have that right,based on memory of OP description.

On Fri, 28 Nov 2014 08:01:56 -0700, Jim Thompson
wrote:

On Thu, 27 Nov 2014 20:11:58 -0500, Martin Riddle
wrote:

On Thu, 27 Nov 2014 16:43:17 -0800, Robert Baer
wrote:

Jim Thompson wrote:
On Thu, 27 Nov 2014 18:14:07 -0500, Martin Riddle
wrote:

On Thu, 27 Nov 2014 11:20:38 -0700, Jim Thompson
wrote:

On Sun, 12 Oct 2014 12:45:29 -0700, Jim Thompson
wrote:

I need a SWAG on this, just to see if it's feasible...

Two inductors (solenoids) with Ferrite cores, each ~5mm in diameter
and separated by ~5mm spacing.

What coupling coefficient might I expect?

(Essentially no load on the "receiving" inductor except natural
losses... and I could tune or not.)

...Jim Thompson

Customer built a PCB and is getting good data coupling out to 2"
spacing.

Both ends are tuned with Q~10, so I'm going to cut it back a bit, I
fear cross-talk issues when he implements multi-channels.

...Jim Thompson

Can he put alternate channels on the opposite side of the board?
Or maybe a EMI shielding enclosure, might cause a change in the
inductance of the coil a bit.

Cheers

Customer has 1' PCB panels... Single inputs on N and W sides, outputs
on E and S sides.

...Jim Thompson
Sheet of mu metal placed at 45 degrees?
Stuff is rather good even at 60Hz and would get better as frequency
goes up.
Tie sheet to system ground plane, natch.

I've seen FM radios with a small single wall shield next to inductors
to break up the field. As long as the inductors are mounted 90deg from
one another coupling is at a minimum. I vaguely recall coils are
needed, so toroids are out of the question.


Cheers

http://www.analog-innovations.com/SED/MagneticDataCoupling.mov

...Jim Thompson

Oh I see now. Spooled inductors are wonderful emitters. Yep a lower Q
and I'd imagine separate TX and rx frequencies.
I believe there is specific EMI limits for intentional emitters if he
eventually goes for some type of certification. It could be either be
bad or good

Cheers