Monday, October 22, 2007

An Early Radio Transmitter

From Alfred N. Goldsmith, "Radio Telephony" (Wireless Press, 1918). The Alexanderson Alternator was an alternative to the spark gap for transmitters. It had a rotating disk with many individual windings such that the edge of the disk could cut magnetic flux lines at a relatively high rate ... perhaps even 100 KHz! These were popular for a while, but eventually transmitting tubes replaced them for continuous signal generation at high power.

Tuesday, October 9, 2007

Early Bloggers Arranging for Publication

Another eBay item, this time from eBay seller blancetnoir in category Art > Prints > Antique (Pre-1900) > Other.