Thank you for checking the Detecting the Invisible page of N4MQU.  One day I was looking at my hobbies and soon discovered most of them have something in common. You are not able to see them. Some stars you need a telescope to see.  Amateur Radio requires a radio to hear the signal. Finding things under the ground requires proper detecting equipment. A camera can freeze a moment in time.  Talk radio requires electronic equipment to receive a signal. DC To Daylight is the term I used for listening to radio scanners, long and short wave radio signals.  The name of my Youtube channel is Detecting the Invisible.