After enjoying the stories on the Link Aviation Trainer and the
connection with the player piano, I thought I should mention that
there was another connection with war time and the player piano --
a connection that lasts right into the present day.

Hedy Lamarr became romantically involved with composer George Antheil.
As the story goes, Lamarr was listening to Antheil play piano and was
thinking about how to make an anti-jamming radio control for torpedoes.

A little bizarre, don't you think?  It's no wonder Antheil didn't back
away slowly, then move to an undisclosed address in Greenland!

Anyway, the constantly changing notes gave Lamarr an idea: instead of
sending radio control signals to a torpedo using one frequency, which
can easily be jammed or intercepted, send it over constantly changing
frequencies in a pre-arranged pattern, like notes in a song.  If both
the sending device and receiving device are synchronized on the same
pattern, they'll be able to communicate.  An enemy who doesn't know the
pattern would never find the signal.

In that pre-electronic age, Antheil designed a mechanical player-piano-
type device that would provide the pattern for the sender and receiver.
On Aug. 11, 1942, they were awarded patent 2,292,387 for their "Secret
Communication System."

The Navy never used it, mostly because it wasn't possible to squeeze
a player-piano contraption into a torpedo.  After the war, the concept
of frequency-hopping faded to black.  No one did anything with it until
engineers at Sylvania Electronics dusted off the concept in 1957 and
used transistors to make it work.  It was first used on ships sent to
blockade Cuba during the 1962 missile crisis.

Now the concept is called spread spectrum, and more than 1,000 spread
spectrum patents have referred back to the Lamarr-Antheil patent as
the basis for the technology.  Qualcomm's code-division multiple access
(CDMA) cell phone technology is based on spread spectrum.  So is
high-speed, 802.11 wireless Internet access.  So is the U.S. military's
Milstar satellite communications network.

It turns out the technology is good for more than just secrecy -- it
allows many times more devices to operate in the same radio spectrum
without interfering with each others' signals.  Though my CDMA cell
phone and yours operate in the same spectrum, they don't interfere
with each other because they're working off different patterns of
microsecond frequency changes.  The signals never bump into each other.

Lamarr died in 2000, but by then wireless devices based on her idea
had spread around the globe and changed the way people live and work --
an important connection with our hobby that has been mostly lost to
history.

Ken Vinen
Aylmer, Ontario, Canada

 [ MMDer Paul Lehrman, who is quite adept with both machinery
 [ and music, reviewed a recent book entitled "Hedy's Folly" on
 [ this topic and noted that many misconceptions and myths continue
 [ to be perpetuated.  Read Lehrman's thoughtful book review at
 [ http://www.mmdigest.com/Archives/Digests/201201/2012.01.09.02.html 
 [ Other MMD articles about Hedy Lamarr are indexed at
 [ http://www.mmdigest.com/Archives/KWIC/L/lamarr.html  -- Robbie