U.S. Heavy Sixers, at least the early ones, were dedicated to channel 2 and did not have a channel select switch. The text on the Epoch import states that the console can only be used on channel 2. However, which channel 2? The U.S. channel 2 is in the 54-60MHz band, but the Japanese Channel 2 is in the 96-102MHz band. U.S. and Japanese TVs of the time did not have the ability to receive at the other country's respective frequencies. Therefore, I cannot see how these systems would have worked in Japan unless Atari or Epoch modified the RF modulator inside the system.
Also, that connector may look like a 300-75 Ohm Balun, but I think it is more likely to be a right angle coaxial connector that someone put on as a mod. Japanese TVs tended to support both 300 Ohm separated pair and 75 Ohm single wire connections, but earlier TVs require the user to twist a wire around a screw connector and clamp the ground shielding for 75 Ohms. Later TVs may have come with a coaxial screw.
Edited by Great Hierophant, Sun Apr 2, 2017 10:12 AM.