How to measure LTE level with any RANGERNeo field strength meter

April 1, 2016.

All PROMAX HD RANGER field strength meters can be used to evaluate and eliminate LTE interferences on television reception. In addition, more advanced models (HD RANGER 2 and HD RANGER +) have one built-in LTE filter to simulate a real filter over television reception when there are LTE signals (4G mobile).

Our analysers have a 7" display (about 18 cm) that shows on screen spectrum, measures and decoded image at the same time. The ultra fast spectrum analyser includes professional features such as MAX Hold, MIN Hold, markers on trace, storage data, measures comparison and high precision in the trace of the spectrum.

All PROMAX HD RANGER field strength meters can be used to reduce LTE interferences
All PROMAX HD RANGER field strength meters can be used to reduce LTE interferences

In addition to other tools such as echoes, constellation, attenuation test and task planner, PROMAX keeps releasing new tools for its meters. In this article we will focus on measuring level and power for the LTE signal.

Select the bandwidth for the LTE signal

First go to the F2 function key and then select GENERIC in the Signal type menu.

Select the GENERIC signal type
Figure 1: Select the GENERIC signal type

Once selected the GENERIC signal type, the field strength meter allows you to adjust the bandwidth for the LTE signal. Typically the bandwidth is 10 MHz, so user can measure each operator in both downlink and uplink.

However sometimes operators share its spectrum with other operators. In this case we must choose the appropriate bandwidth, 5 MHz.

Choose the bandwidth
Figure 2: Choose the bandwidth

The meter will alert us that these conditions are not acceptable to demodulate this signal.

Work in FREQUENCY mode (not in CHANNEL mode)

As an example, the LTE frequency band for digital dividend in Spain it is as follows:

BLOCK OPERATOR DOWNLINK UPLINK
AORANGE From 791 to 801 MHzFrom 832 to 842MHz
BVODAFONEFrom 801 to 811 MHzFrom 842 to 852MHz
CTELEFONICAFrom 811 to 821 MHzFrom 852 to 862MHz

Therefore, we must set the center frequency for each link and each operator. For example, 796 MHz is the center frequency for Orange downlink.

Work in FREQUENCY mode and adjust the Span
Figure 3: Work in FREQUENCY mode and adjust the Span.

Measuring

Finally, we measure. In Figure 4 we can see the signal level (85.3 dBµV) with bandwidth at 10 MHz and the proper center frequency. This signal has been captured in Madrid.

The maximum power that can emit a base station by Spanish law is 63 dBm. The following link shows a table of equivalences between these two measurements units:

https://www.maximintegrated.com/en/app-notes/index.mvp/id/808

Nivel de señal de LTE en dBµV
Figure 4: LTE signal level in dBµV

The PROMAX HD RANGER can receive notifications about new features and also about firmware updates to improve its performance. For example, this power measurement for LTE is added to the LTE Ingress Test already available. This LTE Ingress test measures the signal level with and without filter. In Figure 5, you can see how an external cavity filter can reduce the LTE signal from 86.55 to 54.55 dBµV.

LTE Ingress test
Figure 5: LTE Ingress test