On Mar 14, 2:15 pm, Artem wrote:
....

I mean that I will use you suggestion about balanced amplifier. I'll
use two FETs. I'll place one more tube from middle of the loop to the
gap. And I will use this point as ground point for balanced amplifier.
In this case I will have differential signal at FET Drains and I will
need transformer for put this signal to coaxial cable.

The transformer can be physically quite small.


Yes...very good. That should help keep the loop nicely balanced,
especially if you build it all very symmetrical. That one more tube
can also then help support the loop mechanically. Good luck with your
project!

Cheers,
Tom