Using Simple Tools for Better Communication. Whether you’re driving a Jeep down a dusty trail or communicating with your Jeep convoy, a CB radio is still a solid tool in the toolbox. But even the best CB radio won’t perform right without a proper tune-up, and that’s where an SWR (Standing Wave Ratio) meter comes in. In this guide, we’re using the Workman SWR meter, an affordable and effective option to dial in a CB radio for peak performance.
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What is SWR and Why It Matters
SWR is a measure of how efficiently your radio is transmitting power through the antenna. If the antenna is too short, too long, or just poorly mounted, the signal reflects back into the radio, which not only weakens your transmission range but can eventually damage the radio itself.
A properly tuned antenna will have a low SWR reading, ideally close to 1.0:1. Readings over 2.0:1 are a sign something needs adjusting. The Workman SWR meter helps you find that sweet spot.
Tools You’ll Need
- CB radio – Installed and powered up. We are using the Cobra 75WX in the jeepfan.com 1978 CJ-5
- Workman SWR meter – Any standard model will work (like SWR-2T or SWR-M3)
- Short coax jumper cable – 3 ft RG-58 with PL-259 ends
- Antenna – Fully mounted and grounded. We are using a Firestik NGP (no ground plane) antenna.
- Open space – Tune outside, away from buildings or metal structures
Step-by-Step: Tuning with the Workman SWR Meter
1. Connect the Meter
Locate the back of your CB radio.
- Disconnect the antenna coax from the radio.
- Plug that antenna coax into the “ANT” port on the SWR meter.
- Take your jumper cable and connect it from the “RADIO” port on the SWR meter to the CB radio’s antenna input.
You’ve just inserted the SWR meter inline between the radio and antenna.
2. Set the Channel
Choose Channel 1 and then later Channel 40 for measurements. These will help you see how the antenna performs across the CB band.
3. Calibrate the Meter
Flip your CB to AM mode (if present) and make sure it’s not on PA.
- Set to Forward: Set the SWR meter’s function switch to “FWD” or “Forward”.
- Key the mic (press the talk button but don’t speak).
- While holding the mic key, turn the CAL knob on the meter until the needle hits the “SET” mark.
- Release the mic.
That’s your calibration. Now it’s time to read SWR.
4. Check SWR on Channel 1
- Switch to Reflected: While still keying the transmitter, switch the SWR meter’s function switch to “REF” or “Reflected”.
- Read SWR: Observe the SWR reading on the meter. This is the standing wave ratio.
- Note where the needle lands. Write it down if needed.
5. Repeat on Channel 40
- Change the radio to Channel 40.
- Repeat the calibration process and take another SWR reading.
Understanding the Readings
| SWR Reading | Status |
|---|---|
| 1.0 – 1.5 | Excellent |
| 1.5 – 2.0 | Acceptable |
| Over 2.0 | Needs tuning |
Now compare Channel 1 to Channel 40:
- If SWR is higher on Channel 1, your antenna is too short — lengthen it slightly.
- If SWR is higher on Channel 40, the antenna is too long — shorten it a little.
- If both readings are high, you may have a grounding issue, bad coax, or poor mount location.
Adjust the antenna in small increments, then retest both channels. Patience wins this race.
The Firestik antennas use a clever length adjuster in the top of the antenna. Pop off the red cap and thread in/out the end to increase or decrease the antenna length. Other makes of antennas usually have some sort of tuning method that allows adjustments.
Pro Tips
- Use a mirror mount, fender mount or solid body mount with a solid ground. Poor grounding ruins everything. In the case of the jeepfan.com 1978 CJ-5 the fiberglass body makes for a terrible ground plane and tuning a CB is extra difficult. The NGP antenna from Firestik was the only antenna we’ve used that could successfully be tuned.
- Don’t tune in the garage. Nearby metal skews your readings.
- Don’t key the mic without an antenna or meter connected. You’ll fry your final output stage.
- Recheck after major Jeep mods. A new rack, tire carrier, or bumper can affect your CB’s ground plane and SWR.
Final Thoughts
The Workman SWR meter is a reliable tool that gives you a lot of clarity for not much money. Once your antenna is tuned properly, you’ll get better range, clearer audio, and longer life out of your CB setup. Whether it’s trail chatter or convoy comms, taking 15 minutes to do a proper tune-up is worth it.
And with the Workman meter, it’s just plain simple and easy to understand. SWR tuning is possible on GMRS radios too with the proper meter.
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