F-Display:
Numbers represent signal strength
Signal strength should be about the same on all IF's (indicates "fringing")
RMS = "Root Mean Square"; should be close to zero (this is noted in observe log in VLBI phased array programs every hour)
IF's A & C are same frequency, different polarization
IF's B & D are different frequency, different polarization (different from AC frequency by 50MHz)

For help, with cursor in window type "shift+?"