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The system was to use AM stations all broadcasting the same networked message in a rotating pattern with the stations going on and off the air randomly so they couldn't be used for aircraft homing=in purposes. Probably 99% of the people had some kind of AM radio and transistor portables were coming on the market. AM radio was king with FM really in its infancy then, not many people had sets and I don't think there were any portable sets. It was relegated in many cases to just simulcasting the AM program or playing background music, etc. TV was big and bulky and would be left behind in a dash for cover. I believe that FM and TV stations would broadcast a message to turn on 640 or 1240 AM radio and then go off the air.
I remember listening to a test of the system back then in the late '50's: the AM band was dead as all stations had retuned to one of the two frequencies. In a particular area they rotated air time for a few seconds, so the signal went up and down and changed tone a little depending on which transmitter was on.
Reece
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Reece
Perfection is hard to reach with a screwdriver.
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