MFJ-912, REMOTE BALUN BOX, W9INN
Use coax from antenna tuner to MFJ-912 mounted outside. MFJ-912 converts unbalanced coax to balanced transmission line (ladder).
Giant 2-core 4:1 balun wound with Teflon wire connects to high voltage ceramic feedthru insulators.
Handles full legal limit with ease. SO-239 connector.