Wayne, Perhaps mine, here: http://www.karinya.net/g3txq/chokes/ Steve G3TXQ On 01/03/2012 20:47, Wayne Kline wrote: > Some time ago a Fellow TT'er posted a link to a "G" ham who had done extensive testing showing graphs exhibiting Freq Vs core material and number of windings ect. any one have the link ? I seem to have lost it :( Wayne W3EA >