Toroid Box for FT240 and FT140 Cores - EFHW 49:1, 9:1 Unun, Choke - SO-239, N or BNC (parametric)

A printable box for the transformer of an end-fed half-wave antenna, or a 9:1 unun or 1:1 choke, wound on an FT240 or FT140 size ferrite core. The core sits on the floor round a centre post. A printed disc and one nylon M4 screw clamp it, so it can't rattle loose up a mast. The connector end comes in two versions: a 4-hole square-flange wall for an SO-239 or N socket, or a D hole for a BNC bulkhead. There's an M4 stud hole for the counterpoise on the side, and an M5 stud hole for the antenna wi…

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