Is that just a BNC adapter over the antenna SO-239 ?
I don’t think you need a full 270 volts for the B.
If it were mine, i think i’d try to hit around 220 – 250.

BTW, not to deprecate this receiver at all, particularly this unhacked example,

but i wonder something about the R.E. Goodheart Co. advertised receivers.

On what bands could you actually resolve SSB, considering no bandspread and

no tunable BFO ?

-Hue Miller