Rugged Radios Tech Tip : How to Use a SWR Meter

In today’s video, we’re going to talk about using an SWR Meter to calibrate the performance and effectiveness of your antenna and radio. However, before we can properly test your antenna and radio, we have to be sure your antenna and coax cable are properly installed. First, make sure you have NO excess coax cable coiled up. Coiled antenna cable is a performance killer and is often the number one problem for radio performance. It’s always ideal to cut your coax cable to length and re-attach a connector. We even offer another Tech Tip video online on how to install a coax connector. For whatever reason if that’s not an option, work your coax cable throughout your vehicle, using up the full length and avoid crossing the cable over itself or putting it near power lines. If your cable is installed correctly and your antenna is properly mounted, we can begin using the SWR Meter to test the transmit and reception power of your radio. Technically, we could delve much deeper into the complexities of radio frequencies and theory, but for the purposes of this video, we will cover the simple basics in order to enable you to self-tune your antenna installation. The SWR Meter has three buttons. A red power button, a blue menu button, and yellow navigation button. By default, the SWR meter is set to go “as is” and requires no menu changes. If, however, you accidentally change a menu setting, simply power the unit off. Then press and hold the red power button until the display says “restore to default”. And, one more thing before you begin… make sure you’re testing in an open area at least 20 feet or more away from any buildings or structures. This is not something you want to do in a garage or carport. To begin, connect one end of the SWR meter to the antenna port on the back of your radio. Connect the antenna you just unscrewed to the other side of the meter. With your radio powered on, press the button on your hand mic or the PTT button on your steering wheel to test a transmit. The top right corner of your SWR meter will indicate how many watt’s your radio is transmitting on and the larger number on the center of your screen is called reflective. Ideally, this number should be somewhere around one to one and a half. If you’re testing a 60-Watt radio as we are in this demonstration, with a proper installation, you should see results somewhere between 50-60-watts depending upon the frequency you’re transmitting on. It’s important to note that output will vary by frequency, so getting close to your target radio’s output is a great place to be. There are too many factors to guarantee you will get a true 60-watts out of a 60-watt radio at every frequency. That’s not uncommon, nor a sign of improper installation. Assuming the coax cable and antenna are properly installed, the first thing we do at Rugged Radios to resolve poor SWR test results is tune the antenna. Tuning an antenna is a critical process of cutting the antenna in careful increments to get it to the optimum length for the frequency being used. An antenna tuning cut chart is available online under our help menu. Following the guide, we cut the antenna in small increments to the proper length and continue testing. It’s important to cut and test in small increments because you can always cut shorter as you go, but you can never put back what you’ve removed from your antenna. If your cutting and testing isn’t yielding improved SWR results or they’re getting worse, stop tuning the antenna, and consider that there may be something else effecting your radio’s performance. Common sources of poor SWR results include: antenna not cut to proper proper length (you can find an antenna tuning guide in our help section) Another problem is coiled coax cable. Again you never want to have coiled excess cable in your vehicle. damaged coax cable from heat, cuts, or pinching if you suspect heat, it’s possible there’s damage inside underneath the sheath that’s not visible form the outside. Other possibilities include damaged or improperly installed coax connector. Again, we also have another video available to guide you on replacing your existing coax connector. Other problems could be bad antenna grounding which can be fixed with an NMO-GROUND cable. Next thing to explore is if your radio is powered straight to the battery? It should be for best performance! So, examine those areas carefully. In almost all instances, the root of your problems will reside there. And, when you’re ready to test your radio’s performance, you can get your own SWR meter, the same one we use in the field, at So there you have it — your crash course on how to use an SWR meter! Thanks for watching and keep an eye out more Tech Tip Videos from Rugged Radios.

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