OCFMasters spent two years delving into the ins and outs of End Fed antennas. Throughout that time, we discovered that most End Fed antenna transformers used higher impedance transformations than necessary and were wound in a way that limited the high frequency response of the transformer.
The transformer secondary is wound first with 12 turns of the #18 enamel wire using the tie wraps to hold the ends. Next, the 2-turn primary is wound over the center of the secondary and the 56pF capacitor and wires are soldered to a S0-239 coax connector.
If you are using a wire counterpoise connect one end of the secondary to the long wire and the other side to the counterpoise (13’ 2” for 80M and 7’ for 40M). If you are using a coax counterpoise, connect one end of the secondary to the long wire and the other end to the ground/shield side of the connector.
This transformer can handle 150 watts SSB, 100 watts CW and 50 watts Digital. It will deliver good performance from 80-6 Meters. Use half power on 6 meters to avoid overheating the transformer.
Kits may include either a white insulated wire or a short piece of magnet wire for the primary.