Re: Tesla coil for wireless data transmission?

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: Ed Phillips <evp@xxxxxxxxxxx>

Ed,

Yes, I'm referring to "METHOD OF SIGNALING, U.S. Patent No. 723,188, 
Mar. 17, 1903 and "SYSTEM OF SIGNALING, U.S. Patent No. 725,605, Apr. 14, 1903.

Regarding the definition of Spread Spectrum wireless 
telecommunications, I think of this as a method in which the energy 
of the transmitted electromagnetic wave is distributed up and down 
within the EM spectrum, in either 1) the frequency domain or 2) the 
time domain.  A modern example of the first technique is Direct 
Sequence-Code Division Multiple Access.  While not identical to 
DS-CDMA, Tesla's method of creating a wave complex through the 
simultaneous operation of multiple resonators each tuned to a 
different frequency also exists within this category."

    I agree with your conclusion under this definition.

"The second technique is digital Frequency Hopping Spread Spectrum, 
described as, "the continual switching of transmitted frequencies 
based on a shared algorithm to minimize unauthorized interception or 
jamming of a radio transmission."  While development the technique is 
often credited to Hedy Lamarr and George Antheil (SECRET 
COMMUNICATIONS SYSTEM, U.S. Patent No. 2,292,387, Aug. 11, 1942), the 
seed of this idea is present in the Tesla patents cited above."

    I didn't see any inference to a time-sequenced schedule of 
transmit frequencies in the Tesla patents but will dig out the book 
and look again.  I thought (maybe because of my mind set) he was 
talking about simultaneous transmissions.  The "Hedy Lamarr" patent 
referred to the use of a specific frequency shifting pattern which 
was known and used by the intended receiver once it has established 
synchronization, whether that be by clock time or recognition of 
signal patterns.  There are a vast multitude of such systems in use 
at the present time, a typical one being the "Have Quick" 
system.  You may have read about the background to the Lamarr patent, 
which I found to be quite interesting.  Apparently she was a pretty 
sharp gal and listened to conversations of her husband, who was a 
Swiss (as I recall) arms merchant.  She seems to have understood most 
of what she heard and out of that came this idea, which was 
apparently novel at the time.  People had of course been using clock 
time to schedule the frequency of individual message communications 
almost since the beginning of wireless but her system involved a much 
more rapid switching and hence greater potential security.

"Of course, the simple alternative to both of the above-described 
techniques is single-frequency transmission.

Best regards,
Gary"

   Agreed.  Simplest, cheapest, and usually the best unless 
frequency hopping is used to increase the possibility that at least 
some of a message will get through in the presence of uncontrollable 
and uncertain interference on any particular frequency.
Ed