a 50 ohm dummy load for amatuer trasmitter testing
as made from found components.
by Ralph Klimek, Oct 2009
dummy load tries to be all things to all RF engineers. It has
paralleled inputs for type N, BNC and the horrible PL259. I did this
because this is easier than trying to find the adapter or adapter cable
when you need it. It has a heavily tapped down sampling output that is
safe to apply to a scope, wavemeter or spectrum analyser and a direct
reading rectifiying voltmeter output.
The resistors came from a
Burroughs Line Printer hammer driver ballast bank. I have been
keeping these at the bottom-most section of the most unused junk box
for the last twenty years because I knew that one fine day there would
be a use for them. What beauties they are, no inductance, built in heat
sink, easy mounting and just the right resistance so that a
simple series parrallel arrangement gives a handy 52 ohms which
is close enough to the ideal. I wonder what happened to the Sage
resistor company ? Probably went bust for making the ideal component!
I am a firm believer in robust , COPPER, metal work for RF. RF and die-cast really dont mix.
The copper for this project came from the usual source, discarded hot water header tanks.
|50 ohm RF dummy load||low impedance RF path through out|
|An invincible army of Dalek drones irreversibly reduces all RF power to mere heat.|
page created: Tue Nov 3 18:42:45 EST 2009