As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
NR 1 COMM NOISY IN PRECIPITATION. THE NR 1 COMM WOULD BECOME UNREADABLE IN LIGHT RAIN. TESTED AIRCRAFT WITH DAYTON GRANGER TESTER AND FOUND LORAN ANTENNA SOURCE OF NOISE IN COMM. REMOVED AND REPLACED WITH HIGH SPEED BLADE, PN 14663-03. FLIGHT TESTED AND PROBLEM CORRECTED.