I wind matching transformers for receiving antennas with 30 AWG wire wrap wire. A BN73-202 binocular core will accept up to 18 full turns (36 passes). The insulation is very tough and it will not short to the ferrite core. The insulation is so tough that you'll need a wire stripper intended for 30 AWG wire wrap wire.
https://www.adafruit.com/product/1446 26 AWG stranded wire from old telephone cables also works very well, will not short to the ferrite core and is very easy to strip. A BN73-202 binocular core will accept up to 14 turns. 73 Frank W3LPL ----- Original Message ----- From: "Mike Waters" <mikew...@gmail.com> To: "MR TREVOR DUNNE" <ei2...@eircom.net> Cc: "topband" <topband@contesting.com> Sent: Friday, February 2, 2018 6:04:01 PM Subject: Re: Topband: Beverage transformer and testing The instructions are at www.w0btu.com/Beverage_antennas.html To test it, put a 450 ohm resistor on the high impedance winding and an antenna analyzer on the low-Z. And make sure there is infinite resistance between each winding and the core, as 73 material is conductive. 73, Mike www.w0btu.com On Feb 2, 2018 9:59 AM, "MR TREVOR DUNNE" <ei2...@eircom.net> wrote: Hi I know it's probably been covered here hundreds of times but I'm looking to make a matching Transformer for a 550ft beverage to 75 ohm coax, I have so bn73-202 cores Also how can I test it once it's built _________________ Topband Reflector Archives - http://www.contesting.com/_topband _________________ Topband Reflector Archives - http://www.contesting.com/_topband