[R-390] Balanced Antenna Connector

[Barry Scott]

What is the correct designation for the two-pin antenna connector
(balanced) in the R-390/URR (likely the same for the R-390A/URR but I
want to be specific just in case).

Also, I think Chuck Rippel had a connection contraption that used a
resistor (or two) so that 50-ohm unbalanced would match just a bit
better using the balanced connection.  He had a website that depicted
that but I don't know if that still exists.  Anyone know?

Thanks,
Barry - N4BUQ