wrote:
I haven't got an antenna analyser to do the above checks. The toroids
came in a box of stuff from a hamfest. They are in a packet which has
the brand name "Duratech" printed on it.


If you have any means at all of mesuring
inductance, you can go he

http://en.wikipedia.org/wiki/Inductor
Inductor - Wikipedia, the free encyclopedia

Find the formula (#6) for the inductance
of a toroidal ring. Enter the
appropriate values and solve for u
(permeability of the core). Then look at
ferrites and iron power core properties
with the calculated permeability at the
test frequency. You'll probably find
several core materials that fit.

I think that's about all that can be done.

Chuck

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