Interesting situation--if you were somehow generating false radar return signals (and I doubt this could be happening) you should be getting stopped more often by radar patrols. The mobile units have often shown me to be going faster than I am--perhaps it is the large frontal area we have--but I don't have any problems with cops.
Can't explain the gps verification of your speed, if in fact you are speeding.
I think: 1) you got caught one time by a false hit/bad cop or you would be
getting stopped everytime you go by a radar unit--wouldn't be
the first time that has happened to anyone.
2) one time thru a mobile, unmanned radar gun doesn't mean
3) there is nothing in your rig that would be generating a radar-
band signal. iphones/tire monitors--no
Costly mistake, and you are correct to be worried if in fact you somehow are going faster than you think, but if you were, you would have a large collection of safe-driving awards...
2016 Tiffin 40 QBH
2015 38RSSA, traded
2005 TK3 #1869, 10 yrs of memories,
2017 F450 KR--one more Ford is it
2009 F450 4x4-died; 2010 F450-retired