Bendigo Swap find

[Mike K]

Originally Posted by motto

On the topic of radio interference or static, I was intrigued to learn that this was exactly what the early Marconi radio signals consisted of. A Tesla coil and antenna was used to broadcast static that was interrupted with a Morse key to send the message. How stunningly simple is that?

David

Yes , they were known as spark transmitters , they used a gap ( usually two balls ) across which a spark jumped . There was a mechanism that continually interupted the current through the large primary coil , thus creating a buzzing effect , or a constant spark . The Titanic and all the early wireless gear on ships had this setup http://en.wikipedia.org/wiki/Spark-gap_transmitter

The transmitted signal was very broad and dirty , not clean , the signal radiated out on many frequencies apart from the theoretical resonant frequency of the antenna .

Before the use of valve detectors , the receivers were as deaf as a post . They used massive transmit power to get away with having to use the deaf receivers .

Some of the early modulalted transmitters ( voice ) used a weird arc system .

Mike .