IC-703 CW FIlter

Recently installed the ICOM FL53 (250HZ) CW filter in the IC703. This works very well
and it's passband sits nicely centered at 1500 hz with zero IF Shift. This is very
convenient for WSPR QSO mode in USB with WSJT 7 as this is the default center for this mode.

The WSPR Beacon Segment will also be centered when the radio is tuned to 10.1387, for instance. This is a nice operating enhancement for crowded mixed mode segments like 40 meters. It also prevents the RCVR AGC from reducing the gain of the radio when strong RTTY, CW and other Digimode QRM shows up near the WSPR Band Segment.