I use the one mentioned earlier, it used tubes and was in an old QST. The variac is on the power supply that provides the voltage to the RF deck when the carrier is cut off. This circuit uses 3 diodes, a load resistor, and the power supply.
Some circuits use a voltage dropping resistor instead of a power supply, but there is no easy way to adjust the point at which you want the loading to start at. You can also use a panel meter on the power supply (current) to show how hard you are into the loading... Brett N2DTS > > Brett, > > What circuit are you using? The ones I referenced don't > call for variacs or > auxiliary power supplies. > > Dennis D. W7QHO > Glendale, CA
