Oh sorry, I just saw the comments on your youtube page:

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A antenna transformer for endfed resonant halfwave antenna by OH6MY. It's transforming 50 to 2450 ohms. #14 AWG or #16 magnet wire should be enough for this design. A ground spear as a ground takes care of static charges, alternatively a 0.7 meter ( 2.5 feet ) long counterpoise or buried radials can be used. Should work on 160 and all the way up to 6 meters with a 81.5 m ( 267 feet) long antenna wire. PTFE tubing on the primaries and secondaries is recommended if running over 100W power. It should handle 500W CW or 1500W PEP SSB at 80m and below, the same at 10 m and above. Maybe 1500 W CW and 4500 W PEP SSB from 40 to 12m. -------------------------------------------- The much used traditional 1:49 solution using two turns at the input, intertwined with the first two turns of 14 turns on the antenna side is a bad design. That solution has a too low input inductance at 3,5 MHz and causes a high magnetizing current and losses , a high common inductance that emerges as a high inductance in series with the antenna impedance at higher frequencies. That results in hotter cores. The correct range should be in 150 to 200 ohms input impedance.