Re: SSTC As a transmitter.

["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>

Tesla list wrote:
> 
> Original poster: "Gary Peterson by way of Terry Fritz
<twftesla-at-qwest-dot-net>" <glpeterson-at-tfcbooks-dot-com>
> 
> > . . . If you're interested why
> > don't you build some and experiment?  They're quite easy to build.
> 
> Thanks for the suggestion.  I was speaking about the metal-filing coherer no
> practical experience under my belt.
> 
> Gary

	I have some simple drawings of the ones I built here, and can send them
to anyone is interested.  If enough are interested I can send them to
hotstreamer.  For filings I tried pure nickel, coin silver from a
pre-LBJ quarter, and filings from a current nickel.  They need to be
made as fine as possible, and Marconi recommended using a worn out
file!  I washed everything with soap and water and then proceeded to
file and file and file, but finally got enough of each to experiment
with.  The silver seemed to work best, but all of them worked.  You have
no idea how hard coin silver is until you try to file it!  I found out
later the stuff can be softened somewhat by heating to orange and then
letting it cool.  The plugs are brass, filed off at a 45° angle.  I used
the smallest bore glass tubing I could find (ID about 0.192") and
machined the plugs to fit.

	In his "RC boat" patent Tesla mentions "sensitive devices" and
describes how to make them (there or somewhere else, I forget). 
However, I haven't figured out what he's talking about when he describes
how to make the "filings" for his coherers.  If you do a Google search
on "coherer" you'll find a lot of stuff, including at least one web site
(Italian) describing how to make a simple one.  In this case he hooked
an LED in series with the coherer and a 9V battery and excited it with
the piezoelectric spark generator out of an old propane fire starter.  I
tried that and it worked surprisingly well, but you have to turn off the
power and tap the coherer after each activation.  

	More if anyone is interested, as this is a new toy/old toy to playh
with.

Ed