1. Install the SWR Meter in Line
Turn off your radio.
Locate the coaxial cable connecting your radio to the antenna.
Disconnect the coaxial cable from the back of the radio.
Connect the coaxial cable coming from the antenna to the antenna (ANT) port on the SWR meter.
Use a short length of coax to connect the transceiver (TX) port on the SWR meter to the radio's antenna jack.
2. Set the Meter to FWD (Forward)
Turn the SWR meter's switch to the FWD position.
Set your radio to the lowest possible power output (usually in AM or CW mode).
Select the frequency or channel where you intend to test your antenna's SWR (usually near the middle of the band).
Key the microphone (transmit without speaking) or use a CW key to transmit a steady signal.
3. Calibrate the SWR Meter
While holding down the transmit button (keyed up), adjust the calibration (CAL) knob on the SWR meter.
Turn the knob until the needle is aligned with the SET mark on the meter's scale (usually located near the far right side).
This step ensures the meter is correctly reading the forward power (transmitted signal).
4. Switch to REF (Reflect)
After calibrating the meter in FWD mode, release the transmit button and switch the meter to REF (Reflect).
Key the microphone again (transmit) to check the reflected power reading, which indicates how much of the transmitted power is being reflected back from the antenna.
5. Interpret the Results
Low SWR (around 1:1 to 1.5:1): Indicates a well-matched antenna system with minimal power reflected.
Moderate SWR (1.5:1 to 2:1): This is acceptable but may indicate some room for improvement in the antenna tuning or placement.
High SWR (above 2:1): Indicates significant reflected power, which could harm your transmitter. You may need to adjust your antenna or use a different one to bring the SWR down.
6. Adjust Antenna if Necessary
If your SWR reading is too high, adjust the antenna's length or position and re-test.
Repeat steps 2-5 after each adjustment to check if the SWR has improved.
7. Turn Off the SWR Meter
After taking the readings, turn off the radio and disconnect the SWR meter.
Reconnect the coaxial cable from the antenna directly to the radio.
Tips for Best Results
Test across multiple frequencies to ensure your antenna performs well across the whole band.
Always start with low power to avoid damage to your equipment.
Keep your coaxial cables in good condition to avoid issues with the SWR readings caused by damaged cabling.
SWR (Standing Wave Ratio) meters measure the efficiency of your antenna system by comparing the power sent to the antenna and the power reflected back. A low SWR indicates that your antenna is well-tuned and is efficiently transmitting your signal, reducing the risk of damaging your CB radio.
1. Connect the cable from your antenna system into the "ANT" connection on the back of the meter.
2. Take one end of a short jumper cable and connect it into the "TRANS" (the front is labeled "TX") connector on the meter.
3. Take the other end of the jumper cable and attach it to the CB radio's antenna jack
A high SWR across all channels indicates there's something wrong in your antenna setup. Here are some of the most common problems in getting your antenna tuned.
• Poor ground connection - Most mobile antennas need a good ground plane to work properly. Ensure your antenna mount has a solid electrical connection to the vehicle's chassis. Clean paint, rust, and dirt from the mounting surface. If your vehicle has non-metallic parts like RV's and sports carts or if the ground plane is inadequate, you can install ground straps to connect different metal parts of the vehicle, enhancing the overall ground plane.
• Bad coaxial cable or connectors - Inspect the cable and look for damage along the cable. If you see corrosion on the cable or connectors it's time for them to be replaced.
• Improper installation - Check to make sure the antenna mount is attached and check your antenna stud to ensure the nylon washer is where it should be. If you have an antenna stud make sure your nylon washer is in the correct spot. For studs with a PL-259 the isolation washer should be just above the bracket.
• Obstructions - Nearby obstructions can affect your readings. Make sure you're in an open area and that the antenna is positioned so the signal won't be reflected off of the vehicle body or cab.
