STABILOCK 4032 and TETRA MS Test

The MS does not register with the STABILOCK 4032 ("idle updated" is not displayed in "Signalling status" field after measurements have been started with either "CALL BY MS" or "CALL BY BS" softkeys).

Wrong frequency (each system has its own set of frequencies)

You need to find out the channels used by the system that the MS is programmed for. Enter the channel 0 frequency in the DEF.SET menu. (Willtek will make the system codes and frequency settings available when this information becomes public).

Set-up for wrong connector

Check if the signal is applied to the same connector as indicated in the DEF SET menu (RF or RF-DIR; the RF-DIR socket provides 20 dB higher output level).

Wrong MCC (mobile country code) and/or MNC (mobile network code)

Select MCC according to the country in which the MS is used (a list of MCCs is provided in the appendix of the TETRA manual).

Select MNC according to the number of the network (if the code is not known, try a few starting with 1).

BCC=0

BCC=0 is not a typically used value. Try any other value from 1 to 63.

MS does not operate with STABILOCK 4032.

Although TETRA is an open ETSI standard, there are many possible communication problems because the standard defines more than one way to set up a call. In addition, different operating modes are defined (Simplex, Duplex). Willtek is working on solutions for equipment from all manufacturers. In the meantime, measurements can be performed with the TETRA terminal in test mode.

How can I test the transmitter of a TETRA terminal?

There are two ways; either with a terminal in test mode, or with the 4032 simulating a TETRA network. In the latter case, the terminal can set up a call so that it transmits signals to the 4032, which can then be measured. To set up a call, press either the "MS CALL" or "BS CALL" softkey.To perform measurements in test mode, press the "MEASURE" softkey and set the MS to test mode (refer to the MS manufacturer for instructions on how to do so).

Measurement result field displays "-----" in test mode (MEASURE).

No/wrong modulation

The signal may be unmodulated, or modulated with a modulation format other than that of TETRA.

Low power

The RF power may be too low. On the RF connector, apply at least –15 dBm or 0.03 mW. Check the mobile station's power level using the Spectrum Analyzer.

How do I perform receiver measurements?

The receiver of digital transmission systems is tested using BER measurements: A test signal with a PRBS is transmitted to the unit under test, possibly at low power levels. The UUT either recognises the correct bits and counts the incorrectly received bits, or it loops back the received bits to the test equipment. The RF loopback method is not yet available in current TETRA terminals, so manufacturers concentrate on BER measurement in the terminal, relying on the PRBS sent by the test equipment.

I can usually hear the bursts from the MS in the STABILOCK loudspeaker, but I cannot hear them after starting the audio measurements.

The loudspeaker represents the signal that is selected for the VOLTMeter input.

Once the audio measurements have been invoked, the loudspeaker continues to represent the signal at the VOLTMeter input connector. This can be an advantage, as the audio output and input are still available even when the normal RF and modulation measurements have been resumed.

I cannot hear the selected audio signal in the earpiece of the mobile. The audio signal that was input to the microphone of the TETRA terminal is not audible via the 4032's loudspeaker.

Audio signals are not simply FM modulated but digitally coded and transmitted in a binary format over the air interface.

This would require a voice codec, which is not available for the STABILOCK 4032. Willtek is currently looking into other ways of enhancing the audio test capabilities.