How to Use a Dummy Load for Your Ham Radio

These antennas help your radio signal go great distances.

A dummy load is a device that is used in place of a radio antenna on a transmitter when you don't want your signal to radiate very far. According to the federal laws governing amateur radio, you are required to minimize the amount of on-the-air testing of your transmitter. It is often necessary to test your transmitter, so rather than having your signal radiated by an antenna, you can use a dummy load. This allows you to obey the law without spending a lot of money or needing a lot of space.

Things You'll Need

• Transmitter
• Transmission line jumper cable

Instructions

1. Turn your transmitter off.

2. Check to make sure that your dummy load is rated to handle at least as much power as your transmitter provides. If not, don't proceed until you have a dummy load that can handle the full amount of power your transmitter delivers.

3. Disconnect the antenna from your transmitter.

4. Hook up the dummy load to your transmitter by connecting one end of the transmission line jumper cable to the dummy load, and the other end to the transmitter.

5. Use your transmitter in the same way you always do. With the dummy load attached, you can do testing and experimenting with the knowledge that the signal is not reaching very far.

6. Turn your transmitter off, disconnect the dummy load and reattach the antenna when you are ready to use your transmitter in normal operation again.

Tips & Warnings

• It is fairly straightforward to construct your own dummy load out of materials such as incandescent light bulbs if you would like to be able to say you built your own (see Resources).

• Dummy loads dissipate energy primarily in the form of heat. Therefore, be very careful because your dummy load can get very hot and can stay hot even after you have turned your transmitter off.

• Make sure your dummy load is rated to handle more power than your transmitter can deliver.

• Never operate your transmitter without either an antenna or a dummy load attached. Otherwise, your transmitter could be catastrophically damaged.

• You must have the appropriate FCC license before you operate any transmitter.

References

• "Code of Federal Regulations": Title 47 Part 97 Sec. 97.101
• "Code of Federal Regulations": Title 47 Part 97 Amateur Radio Service

Resources

• "The ARRL Antenna Book"; R. Dean Straw (Editor); 2000
• "Federal Communications Commission": Amateur Radio Services
• "American Radio Relay League": The National Association for Amateur Radio
• "Amateur Radio Relay League": Part 97 Amateur Radio Regulations
• The DX Zone: Home Brew Dummy Loads