Application Note

Measuring Antenna Pattern

with the Anritsu S412E

Introduction

The Anritsu S412E can be used to measure and verify antenna patterns with a single operator. The operator

is located at the antenna under test end where a test CW signal is transmitted. The S412E is located far

enough away from the test antenna in “Far field” conditions. Measurements on the S412E are initiated and

observed by the operator on a smart phone. The remote operation and viewing is made possible by the

Ethernet interface with web server on the S412E. For more information on this see Anritsu Spectrum Master

with Web Remote Tools 11410-00846.

In figure 1 the S412E is connected to the internet allowing the antenna under test to be many miles from

the S412E.

Browser on

Smart Phone

Antenna under test

Internet

Router

Spectrum Analyzer

RF input

Figure 1: Block Diagram for Antenna Pattern Measurement with the S412E connected to the Internet

The S412E is used to measure the signal strength from the

distant antenna under test. Figure 2 shows a photograph of

the receive set up. The Ethernet interface on the receive unit

is connected to the Internet through a router. The S412E

with Ethernet interface includes a web enabled interface for

all of its measurement modes. For antenna pattern

measurements the receive unit will be set to spectrum

analyzer mode, zero span, 30 second sweep speed.

The level of the CW transmitter should be sufficient to be

received at the S412E end. The operator will set up the

S412E using the browser on a smart phone. The browser

would be set to the external Internet IP address for the receive

S412E. Using the browser, the receive unit would be set to

single sweep in zero span mode. Sweep time should be slow

enough to match the rotation of the test antenna. As the

sweep begins the antenna would be rotated 360 degrees.

The resulting measurement trace on the remote unit can be

viewed on the smart phone display and saved as needed.

Antenna pattern measurements are often made in remote

locations to prevent over the air signals from interfering

with the measurements and the test signals from interfering

with others.

The S412E can be used as a WiFi “Measurement WiFi Hot

Spot” with the addition of a small USB powered WiFi router.

With this setup the smart phone can be used to operate the

S412E without an internet connection.

Figure 2: Showing the S412E connected to the

internet through a router and an omnidirectional

test antenna.

Figure 3: Block Diagram of S412E as a Measurement “Hot Spot”

Browser on

Smart Phone

Antenna under test

WiFi Router

Ethernet

Spectrum Analyzer

RF input

Signal Generator

USB