[TowerTalk] Coefficient of coupling

[Jim Lux]

At 08:07 AM 9/26/2005, Tom Rauch wrote:
> > Did you look at this month's QST?  You can build what
> > you need to measure this for less than a buck
>
>
>October? What page?

The article starts on page 36, "A Low Cost Automatic Impedance Bridge", and 
describes using a sound card as an impedance bridge.  It's an excellent 
example of using the computational power in a PC and a sound card to do 
something fairly useful.  At audio frequencies, the parasitics and 
calibration standards will work just fine.

However, it will be at AUDIO frequencies, and if there's anything where you 
really, really want to make the measurements at RF, it's antenna components.

Also, there's the issue of wanting some sort of design tool to get in the 
ballpark in the first place, and that's where programs like INCA are really 
handy. The only thing that INCA doesn't do (at least as of a year or so 
ago, Antonio might have updated it since then) is deal with skin and 
proximity effect.

Paul Nicholson has a program called ACMI which does mutual inductance and 
coupling as well. http://www.abelian.demon.co.uk/acmi/
I believe Paul's program uses Grover's tables.

Another similar program is called MandK by Mark Rzeszotarski is available at:
http://hot-streamer.com/TeslaCoils/Programs/MANDKV31.PDF  for the docs
http://hot-streamer.com/TeslaCoils/Programs/MANDKV31.ZIP for the program

MandK uses direct numerical integration.  I think it also does take into 
account skin effect and,maybe, proximity effect.

For the real hard core.. There's probably eval versions of something like 
HFSS or Maxwell3D around.
Try: http://www.ansoft.com/ansoftdesignersv/

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