I recently purchased 2 little voltmeters they look like the sort that would go in a control or instrument panel they are connected with just 2 wires which provide the operating supply ( they light up green and red) however the green one states it will work between 20and 500 volts and the red one between 60 and 480 volts. When they are both on the green one indicates normally around 241 volts the red one shows 235 volts why the discrepancy I know it's not much but makes you wonder if one of them is lying. Secondly I've noticed that the green one tracks voltage changes faster than the red one and that a few times the green one jumps down to 238 then up to 241 multiple times while the red one stays the same and I think can see a slight flicker in my filament lamps when this is happening incidentally both meters are connected to the same plug a 2 pin 5 amp one
One of the problems is that GPS jammers (that deny a signal) and the more expensive spoofers (that make it look like you are somewhere else) are surprisingly simple pieces of kit, and have a huge advantage in not needing much transmit power, being a lot closer to the earth than the actual satellites, that have to be run with the lowest sensible transmitter power, being solar powered.
So the jammers have a huge advantage, and while having one is a serious offence , to find the small and often battery powered things can take quite some time, and if used sparingly, they may simply not be found at all. They are sometimes used, maybe in conjunction with mobile phone jammers, by criminals to confuse and delay the arrival of police etc, and less seriously by some van and lorry drivers to confuse company tracking systems, so it is not obvious that they have been visiting a girlfriend or doing a private job when they should have been somewhere else. (think as of you Sat nav as calculating your position from the stars, but they are artificial stars that we put up there, and they broadcast their locations so it is done by timing to deduce distance, rather than angles, the jammer is something like a floodlight in front of the telescope, while the spoofer is more like a carefully controlled firework display that looks a bit like a different constellation.)
The most likely explanation for your non existent movement is that a vehicle with one was driven past while you were working. Mercifully, such events are rare, but far from unknown.
One of the problems is that GPS jammers (that deny a signal) and the more expensive spoofers (that make it look like you are somewhere else) are surprisingly simple pieces of kit, and have a huge advantage in not needing much transmit power, being a lot closer to the earth than the actual satellites, that have to be run with the lowest sensible transmitter power, being solar powered.
So the jammers have a huge advantage, and while having one is a serious offence , to find the small and often battery powered things can take quite some time, and if used sparingly, they may simply not be found at all. They are sometimes used, maybe in conjunction with mobile phone jammers, by criminals to confuse and delay the arrival of police etc, and less seriously by some van and lorry drivers to confuse company tracking systems, so it is not obvious that they have been visiting a girlfriend or doing a private job when they should have been somewhere else. (think as of you Sat nav as calculating your position from the stars, but they are artificial stars that we put up there, and they broadcast their locations so it is done by timing to deduce distance, rather than angles, the jammer is something like a floodlight in front of the telescope, while the spoofer is more like a carefully controlled firework display that looks a bit like a different constellation.)
The most likely explanation for your non existent movement is that a vehicle with one was driven past while you were working. Mercifully, such events are rare, but far from unknown.
