I use an old Kenwood TS 520 as my IF for all of the bands and I use 28 MHz as the IF for all of the bands. The TS 520 noise blanker will take a line noise "hash" that is 20 DB over S9 and "ELIMINATE" it COMPLETELY! The desired signal will "jump out" at you. I use the NON-synthesized TS520 at 28 MHz to eliminate "birdies" and "phase noise". 73 es GL Jerry W7QX