I have been having issues with my speedo going to 0mph and originally thought my speed sensor was going kaput.

It happened again yesterday after going past a speed check sign which has happened before in the same place. Looking at other instances of this, i have been close to radio masts at the time of this issue.

It has only happened in these places and does not seem to be a coincidence. Has anyone else ever heard of this?

 

I think you are over thinking this. Odds are your speed sensor is on its way out, or a dirty/bad connection. My bike did this a few summers ago, the speed sensor would periodically read 0. Now it stays at 0, and I need a new sensor. Radio waves are everywhere, if speed sensors were affected by radio waves, no one would know how fast they were going.

 

I hadnt decided that this was the actual problem, it just seems a bit strange to be a coincidence with it happening twice in exactly the same place to the nearest few metres.