|
|
The spark gap is the essence of this transmitter. When it goes active it shorts out the output capacitor. When that happens the RF energy is produced at the points of the gap because the electrical charge energy is separated from the electron current. The electron current crosses the gap and the charge energy that arises at each point heads in the opposite direction towards the antenna.
The hot ionized air that is caused by the spark has to be blown away or the gap cannot turn off properly. That is done by a tiny nozzle directly below the gap. A vacuum cleaner or a hair dryer provides the air pressure. The nozzle is made from the applicator tip that came with a tube of Goop adhesive. It is glued in place inside the electrical plug the holds the spark gap and the antenna. Any similar non metallic small tube could be used.
The spark gap
The spark gap itself is made from nuts and bolts placed through the holes in the prongs of the plug. The faces of the points are flat with a slight tapering of the edges. The gap is 1/16" wide. It should go active at 2500 Volts. The gap is set to be large enough that the air supply can blow the spark out.