Mike, > A second question, the BN-73-202 cores I use are conductive to a > small extent. I have read it is better to use insulated wire or use > sleeves in the cores.
You should use either enameled wire or something like the wire-wrap wire that Radio Shack (used to?) sells. See below on how I use enameled wire. />I noticed there was about 2.5K ohm between > the core and any of the windings. Your winding is shorted to the core and there could be even a shorted turn. > I assume some of the insulation > go scrapped off the enamel on the wire I was using. Yes, that's what happened....sharp edges at the ends of the holes can slice right through enamel. > I am moving to > insulated wire although that limits the number of turns. Use the wire-wrap wire or "Kynar" wire...it's #30 with a thin, tough insulation....could be Teflon. A small diameter probe, something like a toothpick, will help pack the wire in the core if your need a lot of turns. On using enameled wire...I insulate the holes in the cores with ordinary plastic soda straws. I cut them just a little longer than the length of the core and then slit them lengthwise with small sissors. Then I roll them in my fingers, observing how much excess there is in the "roll" when inserted into the core, then I cut off most of that excess, leaving some overlap. I re-insert the roll into the core and it's ready for use. 73, Charlie, N0TT _________________ Topband Reflector Archives - http://www.contesting.com/_topband