A Dummy Load is a nothing more the a 50 ohm resistor going from positive to negative. You can buy dummy loads of various wattages and styles. Probably the most popular one out on the market is nothing more than a paint can filled with a series of resistors submerged in mineral oil. They are fairly inexpensive and very reliable. They are great for a test bench but, to fumble around in a vehicle with a paint can full of oil can be a bit cumbersome. There are also a bunch of air cooled styles that look like a giant fuse. There are more expensive and less cumbersome ones to work with but a little harder to locate. There is an inexpensive solution that you can build yourself and is very handy for troubleshooting your mobile system.

    Parts List

    Tools Needed

    Assembly

1. Take the two resistors and place them parallel to each other and twist the legs of both resistors together on both ends. What you will end up with electrically is one 50 ohm 6 watt resistor.

2. Slide the resistors into the end of the connector feeding one end of the twisted legs through the center pin of the connector.

3. Cut of the excess legs from the tip and solder them to the center pin.

4. Make sure the outer collar of the connector is installed. Take the sandpaper or file and clean off some of the plating on the back part of the connector behind the outer collar.

5. Take the soldering iron and tin the area you just cleaned. "Tinning" is nothing more than applying a thin coat of solder to the surface, this makes soldering the connections together a lot easier and faster. Since the connector is fairly thick it will take a bit of heat to get the solder to stick, so don't be afraid to get it a bit hot.

6. Take the remaining pair of twisted legs and fold them over to reach the area you just tinned  and cut off the excess then solder them to the connector. Make sure the outer collar still spins freely.

7. Screw the PL259 into the PL258 and your done.

    Uses

    Once constructed this little gizmo is very handy in detecting cable problems. Screw the end of the coax into the dummy load and you should get just about a perfect SWR, if you don't then the cable has problems and should be repaired or replaced. This is also handy for checking your SWR meter to make sure it reads correctly. Just remove the PL258 barrel and screw it right into the back of the radio or meter.

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