Re: Atlantic Leap

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "Ed Phillips by way of Terry Fritz <twftesla-at-qwest-dot-net>" <evp-at-pacbell-dot-net>

> A fascinating experiment, but will almost surely fail. A coherer
> receiver
> has not enough sensitivity, requiring at least several Volts for
> excitation.
> Marconi used a magnetic detector in that experiment, and even so was
> able
> to detect something only due to the huge power used in the transmitter,
> and because there were no other transmissions to interfere with his
> equipment.

	I hope the demo works.  Unfortunately, I agree that the experiment is
bound to fail.  If you read that full web site you will see that those
guys are trying to transmit in the 160 meter ham band.  Although by 1901
Marconi had done a great deal of work on tuned (originally called
syntonic) transmitters and receivers (apparently without knowledge of
Tesla's work), the receiver used for the Newfoundland tests was untuned
because of the variations in the capacitance of the kite-mounted
antenna.  Quoting from J A Fleming's "THE EVOLUTION OF ELECTRIC WAVE
TELEGRAPHY", Chapter VII, "He therefor employed a telephone   as a
receiver, simply connected in series with a coherer of some kind.  Those
employed consisted of tubes containing loose carbon power and cobalt
filings, and also the form of carbon mercury-iron self-restoring
cymoscope already described under the name 'Italian Navy Coherer'". 
Fleming further states that, for these experiments Marconi fully
understood the value of using the best form of "syntonic receiver", the
undertainty of the experiment was such as that "it was "out of the
question" to make the costlky permanent arrangements requisite for
utilizing the best forms of syntonic receiver".  Apparently the
transmitter was essentially untuned, and it's not at all clear what
frequency or mode of propagation really determined the results. The
power is stated as 10 to 25 kilowatts.

	As for the use of the magnetic detector, I'm not sure when it had been
invented, but its main advantage was its stability, not its
sensitivity.  Most of Marconi's long-range stations used the magnetic
detector, but coherers were widely used for some time as well.

> > Perhaps a few banner waving Nikola Tesla protesters would be in order ;-)
> 
> How about a demonstration of radio transmission using a reproduction of
> equimpent used by Tesla? 

	I think this would be an excellent idea, although exactly what
equipment was used by Tesla in his transmission experiments isn't
obvious.  The best description I have seen is that by Leland Anderson,
and unfortunately my copy seems to have mislaid itself, so I can't refer
to it here.  Seems to me he used CW from an alternator, but can't state
that with certainty.

> ..................Is a description of his radio-controlled model
> boat available somewhere?
> 
> Antonio Carlos M. de Queiroz

	Yes, an excellent one from the master himself.  The descriptions in his
patent #613,809 seems to me to be detailed enough to permit building a
faithful replica.  There are other references, including one by John
Stone Stone, which includes photographs, but I can't find them right
now.  While a lot of the description deals with the mechanisms for
achieving control, he gives enough detail of his "sensitive device"
receiver that I think an ambitious person (Antonio, per chance?) should
be able to reproduce it without difficulty.

	I think that the following quote should be of interest to all potential
Tesla worshipers (I am an admirer, but not a worshiper).  It is from
Hugh Aitken's "The Continuous Wave, Technology and American Radio,
1900-1932".  Aitken, by the way, is a noted professor at Amherst and is
known for his scholarship and fascinating description of technological
advancements and their commercial implications.

	In his answer to one of the questions in a questionnaire with his
undergraduate college yearbook he replied to "Next to yourself, whom
would you prefer to be?". And de Forest replied "Nikola Tesla".

	"Wherever you look in the early history of radio technology, you run
into the name of Nikola Tesla.  Tuning circuits, high-frequency
alternators, rotary-spark transmitters - almost any device that became
important in the later history of radio, and you can find an
anticipation by Tesla.  Here was a man always trying great things,
capable of profound insights and startling leaps of the creative
imagination, and yet somehow limited in his ability to his inventions
into commercially viable systems.  We remember Tesla today for the one
case in which he unquestionably surmounted that limitation - his
invention of the polyphase system of alternating currents - and for the
familiar device - the Tesla coil - that replicates the spectacular
demonstrons of high-voltage discharges that Tesla loved to engineer. 
His other achievements are little known except by specialists."  (In
other words, Tesla never quite got his act together when it came to
bringing his work to public benefit.)

	Several interesting points here for Tesla enthusiasts.  First of all 
de Forest, who followed Tesla by only a few years, as a college
undergraduate was fully aware of his work and admired his genius.
Although bright enough de Forest, unlike Tesla, was more of a hacker and
an entrepeneur who commercialized or attempted to commercialize on a
variety of radio-related devices and systems. Instead of trying to
commercialize his inventions Tesla preferred to make more, and write up
his results in a number of remarkable publications and invention
disclosures.  I think that, rather than any conspiracy to "steal" his
inventions, is why his name isn't better known to the world today.  

	As for duplication Tesla inventions other than the "Tesla coil", the
main interest of this group, there is enough hard information available
in his various publications to allow enthusiasts to duplicate many of
his even more interesting inventions.  The workmanship and industry of
the guys on this list is quite adequate to the task and it would seem to
me that insted of looking for bigger pole pigs and longer sparks, at
least someone here might pursue some of his other inventions.  How about
it guys?  I'm too lazy to do it myself.........


Ed

Terry:

	Hope this isn't too far off the subject for you to pass along.  These
are thoughts which have been on my mind for a long time, but it took a
gloomy and rainy morning in sunny Southern California for me to put them
down in writing.