Had a nice man from the CAA give a talk about GPS to one of my local PFA groups. Apparently it's very easy to jam GPS signals and jammers are apparently available in the USA. He also said that in Boston (I Think) harbour there was a complete loss of GPS for a three mile radius which was eventually traced to a harmonic side band signal being emitted from a Radio Shack TV aerial booster that someone was using in the marina. So keep that finger on the map
