All band very effective antenna. Double OCFD invV.

SWR less than 2:1 on all HAM band – 80m 40m 30m 20m 17m 15m 12m 11m 10m 6m

Balun system – 1:4 voltage transformer + 1:1 current choke. Amidon core FT240-K. Silverplated wire 1.3mm

Antenna wire – 4mm copper

My antenna:

Connection diagram:

TRX -> TUNER -> 1:1 current choke -> COAX any length -> Balun system (1:1 current choke + 1:4 voltage transformer) -> Antenna wire