is a little clearer on how widespread the usage is. It estimates that there may be as few as 50 jamming incidents per day in the UK, or as many as 450.
If a jammer is driving by more than 1 of their stations or driving by a station 2 times a day, the whole thing could be explained by a few dozen of them being in use.
http://www.bbc.co.uk/news/technology-17119768
is a little clearer on how widespread the usage is. It estimates that there may be as few as 50 jamming incidents per day in the UK, or as many as 450.
If a jammer is driving by more than 1 of their stations or driving by a station 2 times a day, the whole thing could be explained by a few dozen of them being in use.