Glue three FT -240-52 toroids together using cut paper bag as a spacer.

The layer of fiber will facilitate a good bond that can be separated with a razor if needed.

As a general rule, a single FT-240 can handle a transmitter capable of 200w, a pair is good for 500w, and three will handle 1500w with reasonable headroom.

True power handling will be determined by the impedance mismatch per frequency.

I managed 7 turns (one crossed thru center) using #10 THHN bifilar.

I like to add an additional strand of wire for lashing my solder joints.

This gives a strong “rebar” type mechanical bond in addition to the solder.

#10 Ring terminals are crimped, soldered, and shrink wrapped.

The negative terminal is also heat shrink wrapped.

I use closed cell foam as a pad under the toroids.

I screw down the negative terminal to the SO-239, then I use the long strand to lash the positive terminal to the center of the SO-239.

I flow solder through the lashings to make a solid connection between the two.

Closed cell foam fits snugly over the top of the transformer, and the watertight lid holds it all in place.

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