A look at the published schematic for the MFJ974H (Revision 7, dated
10/24/03) shows a balanced topology fed by a "choked" piece of coax (on
the transmitter side).
One might call it a Capital I arrangement. The vertical is a step
adjustable inductance. Two ganged capacitors (four sets of plates, each
nominally 10-208 pF) are on each side of the inductor. (one gang on the
left and the other on the right) Choked transmitter comes in on the
left and antenna is connected on the right. No means for discharging
accumulated charge appears to be provided. [ I would place something
like a 470 k ohm resistor to common from each of the antenna terminals.]
It will be interesting to learn how this unit performs in the field.
73 Mac N8TT

--
J. Mc Laughlin - Michigan USA