Sort of right? I mean how big is the field? How often does someone move the bed in a hotel room? If you were set up outside a hotel where you knew targets slept, you could program constants for the bed in each room right?

Further if you knew what you were trying to do, you could set up your feedback transmitter in a room, record all the parameters for that room, then move to the next room, Etc.

The problem that Perlman was solving was a lot harder (a moving target) but hitting a nominally stationary target?

I don't suppose the embassy received any gifts of plaques recently? Is playing the Theremin a popular pastime among diplomats?

Embassies are constantly swept for bugs and transmitting radio devices. The security officer in an embassy is always going to be an intelligence officer. Particularly US embassies, are not lax security targets along any dimension.