In article ,
says...
http://www.cqham.ru/trx/volna.html

cool looking radio...I didn't translate but looks like dual
conversion...serious rig.

At that era, (if my memory hasn't gone west) a standard receiving
antenna on *on this side of the pond* was a 400 ohm resister in series
with a 470 pf cap, that combo in parallel with a 1 uh inductor all in
series w/ a 200 ohm resistor...meaning it was purely resistive 300 ohms
at 7 mhz, capacitively reactive below and inductively reactive above.

Wx the comrades would have used the same standard I have no clue.