Evaluate against what?
Hmm seems kind of a silly statement to me as a designer.
Evaluation is the job of component engineering in most companies. They make
sure that the components conform to the specification data sheets provided or
not by the suppliers. Just so you always purchase the same thing.
There are 25 toroid transformers accomplishing various functions in my
highly
successful 8 element receiving array, not counting the 8 in the antenna
elements..
One cannot simply design a broad band transformer from a data sheet having lots
or
little information and expect it to accomplish perfectly its function. Each
function is
generally methodically tested to verify that the transformer does indeed
perform its
function with minor variation. One cannot assume that will happen just because
the
data sheet provides various parameters. About the only thing Fair Rite says
about
wideband transformers is to use High u and few turns. Hmmmm.
My point is this. Jim K9YC has measured cores and provided useful data
for the
masses. This is wonderful but it did not come from any companies data sheet.
Jim
has pointed out what you need to duplicate his efforts. I find no reason to
throw the
baby out with the bath water. Who is to say the Laird ferrites might not work
even
better in a K9YC evaluation. Most successful amateur applications of ferrites
do
not come as a result of the manufacturers data sheet but as a result of some
tests
done by someone in the past.
By thorough evaluation in my circuits, I have found an off brand ferrite to
perform
well beyond my expectations. They were not chosen because of price. They were
also not chosen by what it says on the spec sheet.
Lee K7TJR OR
_______________________________________________
UR RST IS ... ... ..9 QSB QSB - hw? BK
|