Topband: Laird ferrites

[Lee K7TJR]

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