Custom u cores anyone?

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All the VIC coils for the resonant cavity were copper wire.There was stainless wire there,but I never seen any coils made with it.
The core material looked like ferrite,but may have been iron.Don't know for sure.I think that it was a ferrite type,but can't be totally sure.Iron looks like ferrite too.
Don

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Yea the core material in the images look like Ferrite to me also and based on the inductance measurements it leads me to think that it has a permeability around 1000. In Stan's U.S. Patent #5,149,407 (page 19 section 6, line 6) says you can use M27 iron cores for the 5 coil VIC transformer.

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Thank you for the clarification. This is what I thought as well.
The closer we can build the unit to Stan's specs, the better the results will be.

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Tony, thanks for the info.
if the core was around 1000 perm wouldn't it be out of the Vic cards working frequency range?

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The permeability of the cores I'm using is 2000 and the inductance measurements with the same amount of wire as Stan's coils give me at least twice the inductance. Don's showed inductance measurements of 1263mH @ around 75 ohms for L1, with the 2000 perm. cores I'm getting measurements around 2500mH @ around 75 ohms for L1. So as you can see my perm. is too high and thats why Im thinking it should be around 1000. With powder Iron cores Im get an inductance of 350mH, which is too low.

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Cool thanks, then I guess that's the new number to shoot for and see what happens

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Anyone knows were cores with such permeability can be bought. Or if it is possible to fabricate such cores using resin and iron powder?
The nearest I can find are balun rods but have permeability of 400 not 1000

HM

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The powder iron cores that I tested where specially made by MicroMetal, but like I said it only gave me an inductance of around 350mH