You can have the best radio in the world with the best antenna with perfect mounting and placement but if your SWR's are too high with your GMRS radio and antenna, your performance will suffer badly and you could severerly damage your radio.

So what is this SWR thing? SWR means Standing Wave Ratio. Simply stated it is a measurement of how well your transmitted signal travels from your radio thru your antenna and into the atmosphere. When you perform an SWR test, the meter will indicate if your antenna is properly working and provide a reading to help you adjust the antenna for optimum performance. Whenever you install a new radio (GMRS, Ham, Marine, Businees,CB etc) you must perform an SWR check to insure that the power from the radio is being transmitted correctly thru the antenna system (which includes your Coax cable). Even with a pre-tuned antenna like the Midland MXTA11, you should still check it as there could be an issue with the cable.

If your antenna system is not set up properly, it can greatly reduce both transmit & receive range and will eventually damage your radio. When your SWR's are high, the transmit power is reflected back into your radio which is the cause of reduced range and radio damage/failure. Do NOT try to transmit from a newly installed radio of any type without checking and adjusting your system for the reading closest to the perfect SWR reading of 1:1 (1 to 1), however, a reading under 2 is acceptable and 1.5 is very good. Any reading in the "red zone" on an SWR meter is trouble. I also suggest from time to time and after a bone jarring trail ride you check your SWRs again, just as a precaution.

There are all types and brands of SWR Meters. You can buy a cheap $15 meter for your CB but an SWR meter for your GMRS or HAM Radio will set you back $100. A CB SWR meter will NOT work with GMRS or HAM Radios so beware! Truck Stops only sell CB SWR meters so it's pretty simple. For any other type of radio, make sure to buy/use an SWR meter that will test the frequency range your radio operates in!

Do you need to own and SWR meter? No, if you belong to a club like Jeep Expeditons, you will find that there are a number of members that own SWR meters and don't mind helping another member with checking their radio and helping make adjustments. I've known members to even help others with the whole radio installation from mounting the radio and antenna to running the wires. Ham Radio shops will also help you with your GMRS SWRs for a small fee but that is a service you can't get at a truck stop or typical CB shop.

An SWR meter will come with instructions. Its a simple process (below is the process for CB, Ham and GMRS are slightly different:

• Disconnect the antenna COAX cable at the back of your radio
• Connect the cable to the "antenna" end of the meter then attach a short jumper cable from the "radio" side of the meter to your radio
• Set the meter to "Calibrate" or "REF" with the radio on and set to Channel 1
• "Key" your mic and turn the Calibration (could also be labled "SET" or "Adjust") Knob until the needle comes to rest on the line to the very right normally labled "CAL" or "SET"
• Un-key the mic and switch the meter to "SWR" or "FWD" and key the microphone again. Write down the reading on the meter and un-key your mic
• REPEAT this procdure, this time on Channel 40 and write down this reading
• If the SWR on channel 1 is higher than that on channel 40, your antenna is too short.
• If the SWR on channel 40 is higher than that on channel 1, your antenna is too long.
• If your antenna is too long, it will be necessary to reduce its length. Check the manual or install sheet that came with your antenna for detailed instructions on how to shorten your antenna. Many "Stick" antennas feature a “tunable tip” that uses a small screw to secure it, whip antennas have room to slide up and down in their base and are secured by a set screw. Some antennas may need to be cut to be shortened. Make ALL your adjustments in 1/4" increments and then check your SWRs again.
• If your antenna is too short, it will be necessary to increase its length. Many times when the antenna is too short it can be caused by the lack of a ground plane. Options to make the antenna longer if you run out of adjustment would be to add a spring.
• Continue adjusting your antenna "shorter" or "longer" as indicated by your SWR readings on Channels 1 and 40 until your readings are as far under 2 as you can get them.

• SWR Reading above 4 usually indicate an installation problem, not necessarily the antenna length.
• Many high SWR readings are caused by ground plane problems. A sure fire way fix ground plane problems is to run grounding straps from the body of your vehicle to the frame, doors, trunk -- everywhere. Running the shortest possible ground strap from the antenna to the chassis or your vehicle is a great way of fixing ground plane problems too. Proper grounding of everything will improve ground plane.
• Shorts in the COAX cable connectors can be the problem causing high SWR readings. Potential problems with COAX cables can often be identified. Defects like severe bends, kinks, cuts or pinches can cause high readings. You MUST use 50-ohm coax for single antennas and 75-ohm for dual. If all else fails, it's going to be necessary to replace the coax cable because there's a break or short inside the line itself.
• It is absolutely necessar that your mount is properly grounded. Which is why I don't much care for trunk or lip mounts that rely on two set screws gouging thru the paint to make a good ground. Poorly grounded mounts are connected to places on your vehicle that themselves are not thoroughly grounded. Any part of your Jeep that has a plastic or nylon bushing separating it from the chassis is most likely not grounded. Also, your Jeeps paint can prevent a mount from being properly grounded. Always check the grounding of antennas, mounts and what the mount is mounted to and what that part of your Jeep is mounted to with a voltage meter.