his just happened, for the first time ever, over the weekend during the ARRL Sweepstakes Contest and has never happened before. All of a sudden, regadless of band I am using, there will be a dramatic drop, about 1/2, in reception. This is a severe attenuation of several db. I will key up the microphone and it will return to its prior level. However, soon after recovery, it will dip again just as dramatically. It may remain operating normally for several minutes before it does drop again. I have not changed the attenna at any time prior to this happening. I have not changed microphones although the same effect and recovery will happen regardless of the microphone I use. I have not changed computers nor added software to the PC that is dedicated to the operation of the radio. I have an ICOM IC-7410 using the same antenna and when I switch to that rig, everything operates nominally so I have isolated it to the FLEX 3000. Apparently, this issue does not impact TX since I have metered full output when it is occuring on the RX side. It always recovers when I key up the microphone. Also when the RX level drops, do not lose the incoming signal but hear it at a vastly reduced audio level. Any ideas?