What was found
INTERMITTENT ISSUE WITH COMM STATIC. EXTENSIVE TROUBLESHOOTING WAS COMPLETED. THIS RADIO STATIC ISSUE HAD EVERYONE STUMPED. EVENTUALLY THE SOURCE OF THE STATIC WAS TRACKED DOWN TO A RF INTERFERENCE COMING FROM THE RADAR UNIT. NO CREW REPORTS ON ANY FAULTS IN OPERATION OF THE RADAR UNIT DURING THE COMM STATIC ISSUES. SEVERAL RADAR UNITS, 4 EACH, WERE INSTALLED WITH SN`S LESS THAN 3000 & EACH UNIT HAD EITHER BEEN REPAIRED OR OVERHAULED, BUT EACH EXHIBITED THE SAME RF INTERFERENCE WITH THE COMM RADIOS. IT WAS RESEARCHED & DISCOVERED THAT THE RADAR UNITS PN 622-8440-003 WITH A SN LESS THAN 3000 WERE CAUSING THE RF INTERFERENCE. A RADAR UNIT PN 622-8440-003 SN 3750 WAS INSTALLED & NO FURTHER RADIO STATIC INTERFERENCE HAS BEEN REPORTED.