A couple of years ago I old on ebay a portable transmitter and receiver set of WW1 era which comprised a "spark transmitter" which was simply a doorbelltype buzzer powered by a 4.5volt "cycle lamp" b
Hi, Itīs not a matter to laugh about what happen to me I am occasonally do some demonstration in a vacational school with a simple spark transmitter. Such a Xmitter can be easy built with items from