To find out the total interferance you would need a high freq scope. I think there about $10,000 Buy one and let us know. I just know about the cops interferance , just by the screw up tv screen ,when recieving stuff from the x-10 camera.
The interferance can be caused by a reflection from anything , by harmonice etc. Even a solder joint or wire in alignment. High freq is a art of all the parts.
I guess you can build a antenna to pick up the freq of the cops. But then new systems are digital and scrambled. The personal rec/trans are not as high tec as the ground base units.
Note I found out by the cops living next door, so it was easy, I would know they were home by the monitor disturbances.