3 ms·Furthermore, portable RF devices can help rule that vector part out.by egberts1 4y agoFurthermore, portable RF devices can help rule that vector part out.LukeB42 4y agoThey're spies. They just stop transmitting when the signal strength meter person's present. It's not rocket science.egberts1 4y agothey are spies, they’ll make a nice warning device that is concealed, no?