How to Set Up a Ham Shack With Two Radios and One Antenna

Sharing two radios with one antenna requires an antenna A/B switch.

A Ham Radio "shack" is a separate room into which radio equipment is installed for a comfortable and efficient operating experience for the licensed Ham radio operator. With modern Ham radio, operators tend to have two or more radios so they may communicate via satellites and repeaters using one, and over the HF (High Frequency) bands on another. When only one antenna is available to be used with two radios, a switch can be installed to switch between either of the radios when needed.

Things You'll Need

• 1 Antenna A/B switch with two PL-258 coaxial connectors on one end, and one PL-258 coaxial switch on the other (available at Radio Shack, Amateur Electronic Supply, and other radio retailers)
• 2 Coaxial cables with PL-259 male coax plugs on each end
• 1 PL-259 coaxial connector on the indoor end of the coax cable leading to the antenna outdoors

Instructions

1. Turn off both radios and unplug each from the power outlet to prevent any risk of shock to yourself or damage to the radios while connecting cables.

2. Orient the antenna A/B switch so that the side with the two coaxial connectors is facing downward and the single connector on the other end is facing upward. Mount the switch to the wall just behind the operating desk where the radios are sitting.

3. Connect the screw-on male plug of one of the short cables with connectors on each end to the left coax connector on the antenna switch and tighten firmly. Connect the other screw-on male plug on the other end of that same cable to the PL-258 coaxial connector on the back of the left radio. Tighten firmly.

4. Connect the screw-on male plug on one end of the other short coaxial cable to the coax connector on the right side of the antenna switch and tighten firmly. Connect the other screw-on male plug on the other end of that same cable to the PL-258 coaxial connector on the back of the radio on the right. Tighten firmly.

5. Connect the screw-on male plug on the end of the cable exiting the building, and leading out to the antenna, to the coaxial connector facing upward on the antenna switch. Tighten firmly.

6. Plug in the radios to their power sources (wall outlets) and turn them on. To use the antenna for the radio on the left, switch the antenna A/B switch to "A," and to use the antenna for the radio on the right, switch the antenna A/B switch to "B."

Tips & Warnings

• It is simple to identify the kind of antenna switch when purchasing. An A/B switch has two connectors on one end with one connector on the other end, and a two-position switch to select between two radios. An A/B/C switch permits three radios to be connected to one antenna, having three connectors on one end with a fourth connector on the other end, with a three-position switch to select one of three radios.

• Be sure the antenna is designed for the frequency range being used on both radios to prevent damage to the transmitter. If the antenna is designed only for a specific frequency range in the HF (High Frequency) bands, then only those frequencies should be used with either radio when transmitting. More specifically, if the antenna is an HF antenna, then don't attempt to use a VHF or UHF transmitter through that antenna. Both radios should be used only on the frequencies for which the antenna was designed.

• Make sure the A/B switch being used is designed to handle the amount of wattage output the radio transmitter is capable of transmitting. If the transmitter puts out 100 watts of energy, the switch must be rated to handle 100 watts. If higher, the switch should be capable of the maximum output capability of the radio transmitter.

References

• Amateur Radio Relay League (ARRL): Setting Up Your Station (PDF)
• AY Technologies: Station Design Layout (PDF)

Resources

• Amateur Electronic Supply