Report on Signalling with Pulses of Light
[Technical Report, Formal Report]
NAVAL RESEARCH LAB WASHINGTON DC
Pagination or Media Count:
A system of light pulse signalling was developed and tested. Thesource consisted of high intensity flashes of light produced by thedischarge of a 112 micro-farad condenser at 2000 volts through a tubeof argon gas. The receiver was a six stage electron multiplier phototubewith high gain pulse amplifier. With both source and receiver unfocussedthe signalling ranges were 800., 7000 and 500 yards, respectively,for the infra-red, visible and ultra-violet portions of the spectrum.With the source focussed into a 12 cone and with the receiver sharplyfocussed it was estimated that the above ranges would be increasedabout ten times.It was concluded that the ranges were too short to be of muchuse for secret signalling, quite apart from the disadvantages 1that the system is inoperative in daylight and in fog., 2 that,since the system transmits only a few flashes per minute, its use forconveying information is limited.