Standing Wave Ratio Test

Top center SPST switch is to run simulation (show induced signal from transmission line) with no connection to 51 ohm resistor when running SWR meter. Transmitter and antenna is 50 ohm transmission line set up. Start with 4.5 inch piece of RG-58A/U coaxial cable and remove outer jacket and braid to use insulated coax inner lead wire. At center of this wire remove insulation to later solder the 51 ohm resistor. Now, prepare about 4.5 inch of 1/4 inch copper tubing and cut hole in center to solder 51 ohm resistor to center of coax wire inside copper tube. Copper tube is insulated from and not connected to resistor or coax lead wire. Use 50 ohm transmission connectors to add copper tubing into transmission line. To use: with SPDT switch in left position (FORWARD), power transmitter and adjust variable 25 ohm resistor for full scale reading, now, move SPDT switch to right (REVERSE) to show reflected antenna power. This should be near zero for a good match. If upscale reading is shown on meter (0 - 500 uA) , look at transmitter manual and antenna instructions on how to reduce SWR.

published 10 years ago