N4GG's Spark Gap Transmitter
"Blue Lightning," a fully synchronous 1/2 KW rotary spark gap transmitter circa 1910, completed in 2010 by N4GG. Nearly every piece is from the period or hand made using period materials and processes. There were thousands of these in 1910 (though hardly any two alike), there are only a few in existence today. While correct to 1910 methods and materials, this transmitter was built without plans - each amateur did it "his way" in those days.
|
|
Beginning
of final assembly. Note the Thordarson Type R spark transformer
(circa 1910) being used as a weight to hold the mahogany main chassis
in place.
|
|
|
The
completed Leyden jar rack. Indian mahogany with 1910 finish, Copper
from Georgia Copper, Gainesville, GA. The lower tray is designed
to hold one bottle's worth of electrolyte, should a bottle ever
rupture.
|
|
|
Mid
way through final assembly. The knife switches are period - both
are on slate bases. The left switch is a Perkins 250 Amp, circa
1920. The right switch dates to around 1910 - it was used in the
lighting panel of a subway station in the NYC IRT subway system.
It was obtained as a total basket case and had to be remade from
the ground up.
|
|
|
The
completed rig. The key is on the other end of ten feet of wire.
Some folks prefer to operate it that way!
|
|
|
50
KV peak-to-peak on the Leyden jar capacitors. Today this is referred
to as corona - in 1910 they called it "brushing." It wastes
power but it sure is fun to see.
|
|
|
The
gap running around 1,500 amps, 240 breaks/sec. This is why its called
"Blue Lightning." At higher power it should be viewed
through a welders mask - the gap's UV output is not eye safe at
higher power levels.
|
|
|
The
1/2 KW rotary spark gap transmitter in action
|
|
|
|
|
|
|