Mike - Doug DeMaw published some information on using toroids for antenna traps in the June 1983 QST. It has been republished in the ARRL book "QRP Classics", page 180. Toroid based traps will have high Q and hence narrow bandwidth. I hope that this helps. - Dr. Megacycle KK6MC. -- James R. Duffey KK6MC/5 Cedar Crest, NM DM65