While I agree there is not evidence of a weapon, I am not buying hypochondria. The amount of reports and the peculiarity of the hearing symptoms don't add up to hypochondria. Local environmental pathogens or chemicals could be a cause. Also, our ability to detect such pathogens or brain abnormalities is still very limited, so finding no abnormalities is not surprising.
Lot's of people hear low pitched sounds, for decades, and it's been in the news. It must be psychosomatic... oops, we can measure it (~60dB), because we bothered to check. Where's it coming from? Don't know, but maybe NatGas pumping stations?
Now, the reason I doubted that RF was causing this is that enough radio wave power to penetrate skulls at a distance would have been easily detected with some LEDs and short pieces of wire. The idea that there aren't wide band RF detectors in embassies strains credulity. You could put them in glasses trivially. I think it would take me 5 minutes with a soldering iron and parts on hand, and be almost indetectable without examining the glasses.
