On Friday, December 21, 2018, 12:23:44 PM PST, Steven Schear
   <schear.steve@gmail.com> wrote:

   >One has to wonder if the Gatwik dronners simply found a way to modify
   the wifi frequency placing it out of the ISM band and the military's
   radio countermeasures were specifically only for those frequencies.
   That sounds relatively simple.  One problem might be that on a spectrum
   analyzer, a set of WiFi-looking signals, a few tens of MHz from where
   WiFi ought to be, would stick out like a sore thumb.
   The large majority of airport-visiting people have cell phones, and
   many of them will be accessing WiFi at any given time.  It seems to me
   that anybody attempting to control a drone secretly might want to "hide
   in plain sight", using an existing WiFi system.
               Jim Bell