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Antenna Test | Telit Cinterion IoT Developer Community

October 30, 2018 - 8:59am, 2390 views

Hi,

we have  to perform an antenna test on our board which includes a PLS8-E. (Similar to the problem in thread "ELS61-E antenna test" https://iot-developer.thalesgroup.com/threads/els61-e-antenna-test)

In production test we connect one antenna to our board (the antenna interfaces are routed from the PLS8-E pads to MCX sockets). We want to check if the antenna RF paths are connected correctly. No SIM card inserted. To check both antenna paths we think it is neccessary to connect only one at a time and repeat the test for the 2nd antenna socket.

First we limit the band to LTE800 with the command at^scfg=Radio/Band,2097152,1 to force the module into the 4G MIMO mode (can be undone with at^scfg=Radio/Band,2928787,1). In this band and at our location the module usually connects to the vodafone network (MCC,MNC = 262,02). RSRP is usually about -87dB. This can be checked with at^smoni. If the RSRP is worse than -90dB then the board has failed.

But some of the PLS8-E modules (about 15%) decide to use the telefonica network (MCC,MNC = 262,03) which has a RSRP of -115dB. We have to modify our test software to accept alternatively this network with RSRP not worse than -118dB. Or we must insert a vodafone SIM to get always this particular network. Both solutions are not very comfortable.

Is there a way to force the module without SIM card to a particular network and to 4G mode? Or even better to a particular base station? (at+cops works only with SIM)

Is there a test/measurement mode in these modules (in our case a PLS8-E) to check the RF path with a simple non-modulated RF signal? I think testing only one direction from module to measurement equipment or from signal generator to module would be sufficient. We are confident that transmitter and receiver of the module itselft are tested enough at the Gemalto factory.

Or is it better to use a base station simulator? But I think these are usually build for certification testing and are very expensive. We don't want to do a compliance test of the module but just only a connection test of our board. Can you recommend a simple base station simulation?

Regards

Hendrik