How to measure how
good an Antenna is?
Measuring SWR

How to measure how good an Antenna is?
The performance of an antenna can be determined from the following formula:

• SWR = Standing Wave Ratio
• G = Gain
• BW = Bandwidth

The following explains how to determine SWR, Gain og BW.

Measuring SWR

Standing Wave Ratio
The standing wave ratio is normally measured by inserting a
device in the feeder cable of the antenna. How much power
reflected back from the antenna compared to the power
transmitted forward is measured.
Such a device is called a directional coupler.

Directional couplers
Directional couplers or SWR meters for frequencies lower than
150 MHz are relatively cheap and quite accurate.
For frequencies above 400 MHz exact meters are expensive.
The most wellknown universal instrument is a BIRD-wattmeter.

Measuring the standing wave ratio