Re: Spark Gaps

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

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

> Very intriguing,  What is an AMRAD quenched gap?  Where can I get one? or
> are they difficult to make?
> 
> Chuck

	An AMRAD quenched gap is an antique, surplus from WWI, and used in
spark transmitters!  Very rare now and prized by old junk collectors
such as I am; the one I have is the only one I have ever seen in
person.  AMRAD was the name of the outfit that made this particular one
and ended up with a bunch on its hands when war contracts were
cancelled. They then tried to sell them for amateur use, but the marked
dried up as spark went out of style.  As for what it is, easier to send
a picture than describe it, but its of conventional construction for
that period.  Essentially it consists of many flat copper gaps in
series, perhaps 1-1/2" in diameter and spaced about 1/32" apart.  They
are separated by fiber washers and the whole assembly is held together
by a clamping screw.  When it runs the oxygen inside is quickly used up,
leaving mostly nitrogen.  The gap chambers are sealed from the
atmosphere by the fiber washers, with the net result that the copper
surfaces stay clean and pink after many hours of running.

	This type of quenched gap was used for the same reasons they are
valuable for TC's.  They turn off fast...... 

Ed

Who'll mail a picture to anyone who is interested, provided he can find
the bloody file!