CB Power & SWR Meter

Standing wave ratio

In radio engineering and telecommunications, standing wave ratio is a measure of impedance matching of loads to the characteristic impedance of a transmission line or waveguide. Impedance mismatches result in standing waves along the transmission line, and SWR is defined as the ratio of the partial standing wave's amplitude at an antinode to the amplitude at a node along the line. The SWR is usually thought of in terms of the maximum and minimum AC voltages along the transmission line, thus called the voltage standing wave ratio or VSWR. For example, the VSWR value 1.2:1 denotes an AC voltage due to standing waves along the transmission line reaching a peak value 1.2 times that of the minimum AC voltage along that line. The SWR can as well be defined as the ratio of the maximum amplitude to minimum amplitude of the transmission line's currents, electric field strength, or the magnetic field strength. Neglecting transmission line loss, these ratios are identical. The power standing wave ratio is defined as the square of the VSWR, however this terminology has no physical relation to actual powers involved in transmission.

The standing wave ratio meter, SWR meter, ISWR meter, or VSWR meter measures the standing wave ratio in a transmission line. The meter indirectly measures the degree of mismatch between a transmission line and its load.

A Must Have

The Standing wave ratio determines how good your reception and transmission will be. A perfect ratio is 1:1, the maximum acceptable ratio in CB is usually 2:1. If you listen to a 1:1 aligned radio system and a 2:1 or more you will hear an obvious difference in quality. It’s important to keep your radio system aligned not only for the quality though, a bad ratio can hurt your radio device in the long-term, sending it to an early retirement if you don’t take care of it.

Test your mobile CB radio with SWR Meters

Move your vehicle to open ground. If you have instructions that came with your specific meter device follow them. Try not to have any physical barriers such as walls or trees around you. If the ratio isn’t good, try changing your setup. Sometimes you will need to change the length of the antenna, try to do it in ⅛ increments. Try to move your antenna around, make sure it’s grounded well. This is the most important part of your configuration, determining the final position of your antenna and cables. Try not drilling anything in before you do this.

1. Keep your radio healthy
2. Calibrate your setup
3. Determine Antenna positioning
4. Diagnose radio problems

Best Meters for Ham Radio

Many ham radios already have built in SWR/Power meters along with other features. Consider your setup:

1. How accurate do you need your SWR/Power meter to be
2. How much budget do you have. Compare the price and decide on your priorities
3. Which additional features do you need

SWR Power Meter for VHF

The SWR Meters for VHF tends to be a more advanced device, with power meters feature, different sensors and connectivity. These are intended mostly for base stations in ham radio configurations and come with a price. You cannot compare them to the minimal needs of CB radios who are on the HF band.

Not Sure What to Get?

What’s the best Meter for your CB

Consider small SWR meters for Standing wave Ratio. You can also connect that device to your lighter plug or to the fuse-box. Permanent In-line meters would be the easiest to install, if you compare them to equipment you only connect temporarily for check-ups

SWR for Ham/Amateur Radio

For ham radio there are many different configurations and testing equipment, usually they also include built-in power meters to measure transmissions. if you’re not sure what device to get for your configuration. Try to compare the features these products have, call us or send us a message and we’ll help you choose the best product for your setup.