Satu projek Homebrew dari Laman “N2UHC’s radio stuff” yang boleh dibuat percubaan.
This is a simple, easy-to-build dummy load for QRP operation. This design was shown to me by Jay Rupar, K0ETC. It consists of a chassis-mount SO-239 jack and eight 1/2-watt 100 Ohm resistors. The circuit consists of four parallel groups of two resistors in series, giving an overall impedance of 50 Ohms.
Construction is simple. Solder two resistors together in an “L” shape. Do this three more times with the other resistors. Solder one end of the resistor pair to one of the holes in the jack, and the other end to the center conductor of the jack. Do it for all four resistor pairs so that you have 200 Ohms in parallel four times.
The dummy load can be connected to a radio with a short coax jumper or a double-male PL-259 plug.
If 1/2-watt resistors are used, the power dissapation should be at 4 watts. However, it is possible to transmit up to 10 watts into the dummy load for very short lengths of time. 1/4-watt resistors can be used, but the maximum power dissapation would be at 2 watts.