ACR AND CPR ACFT WITH ACARS EQUIP RECEIVE INTERFERENCE ON LCL CTL FREQ 120 PT 0. ACFT EQUIP PROBLEM RADIO.

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THE PLTS RPT A CONSTANT SQUEAL OR STATIC ON FREQ 120.0 FROM THE MOMENT THEY DIAL IN THE NUMBERS AND SWITCH ON THE RADIO. THIS OCCURS WHILE THEY MONITOR THE FREQ AND THEY ALWAYS ASK TO SWITCH TO ANOTHER AVAILABLE FREQ BECAUSE THE INTERFERENCE IS TOO MUCH. THE CTLRS IN THE TWR NEVER HEAR THE NOISE. THE INTERFERENCE IS IN THE ACFT. THE ONLY OPTIONAL FREQ TO SWITCH THESE ACFT TO IS THE GND CTL FREQ 121.9. A POTENTIAL UNSAFE CONDITION ARISES EVERY TIME WE SWITCH THESE ACFT TO ANOTHER CTLR'S FREQ. THIS HAPPENS TOO OFTEN. SUPPLEMENTAL INFO FROM ACN 226604: CONTINUOUS SIDE TONE; RPTED TO SOUND LIKE A STUCK MIKE BY AIR CREWS. PROBLEM AT TIME BELIEVED TO BE ASSOCIATED WITH ANTENNA LOCATION FOR ACARS SYS ON ACFT. NOISE VERY DISTRACTING ON FINAL AND A POTENTIAL ASSOCIATED DISTR IN A DETERIORATED ENVIRONMENT. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE PLANNING PROC SPECIALIST WAS CALLED TO SEE IF ANY SOLUTION TO THE FREQ PROBLEM WAS FORTHCOMING. ANALYST WAS REFERRED TO FACILITY MGR WHO HAD BEEN INVESTIGATING THE PROBLEM. FACILITY MGR STATED THE PROBLEM WAS FOUND TO BE WITH ACFT EQUIP RADIO. CPR ACFT ARE NOW HAVING SAME PROBLEM. OTHER ATC FACILITIES ARE ALSO HAVING PROBLEM. THE INTERFERENCE ONLY INVOLVES FREQS ENDING WITH DECIMAL 0 (120.0; 118.0; 119.0; ETC). MGR STATED HE HAD BEEN CONTACTED BY AN ACR COMPANY WHICH LOOKED INTO THE PROBLEM AND SAID IT WAS CAUSED BY ACARS SYMBOL GENERATOR IN THE ACFT. FAA REGION AND WASHINGTON ARE AWARE OF PROBLEM.