OK Ken.? I used the U3S Park mode LO here on my QRP Labs RX for WSPR
RX (single band) before RX mode was introduced more recently, and
the sensitivity was fine (very little difference between
simultaneous WSPR spots from the QRP Labs RX kit and my IC-7600 when
Tee'd off the same RX antenna).? But I see the need for U3S RX mode
in multi-band RX use.
73, Bob? ZL1RS
