What was found
A/C ORIGINALLY EQUIPPED WITH ANTENNA MOD CI4510-700 IAW LSTC NR C-LSA02-377/D. ANTENNA LATER RECALLED BY MANUFACTURER. REPLACEMENT ANTENNA MOD CI2480-100. DURING FLT, REPLACEMENT ANTENNA VIBRATED LOUD ENOUGH TO BE HEARD IN COCKPIT. ANTENNA REMOVED. INSTALLED SAME ANTENNA IN SAME LOCATION. ON 2 OTHER BEECH 200'S WITH NO VIBRATION NOTICED. OPERATORS HAVE BEEN KEPT ADVISED OF SITUATION WITH OTHER A/C. SPECS SHEET FOR CI2480-100 ANTENNA STATED 350KTS TAS MAX & A CEILING OF 55,000'. SPECS SHEET FOR CI2480-100 ANTENNA TODAY STATES 210KTS IAS MAX AT 10,000' & CEILING OF 20,000 FT. ANTENNA MANUFACTURER WILL BE CONTACTED FOR CLARIFICATION.