Oh, I noticed something else with the RFI I'm getting... I was
trying to zero in on a SSB signal, and from the pitch sweep it
sounded like the RFI "carrier" was sweeping up or down the
bands...

Just FYI, I have a 7600GR with an AN-LP1.


Sounds like your 7600gr is in Sync mode and your tuning a SSB signal.
While the Sync tries to Lock onto a non-existent AM carrier you will here
a sweeping sound as the Sync "seeks" the non-existent AM carrier.