Hi Herb, I totally agree with Jim (KR9U), wind your own since you said you
have 73 material binocular cores.
For my pennants and other low band RX antennas I use BN73-202 binocular
cores. I would probably go with 3 turns on the primary and 10 turns on the
secondary. If you have wire wrap type wire this makes winding the
transformer very easy (no concern of scratching enamel coating off the
wire), and it should just take you a couple of minutes to wind.
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