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CC1101: WMBUS OMS 434 MHz range issue

Eduardo Bernardi
Intellectual 920 points
Part Number: CC1101
Other Parts Discussed in Thread: WMBUS,

Hello,

I ported the Ti wmbus stack for the 434.475 MHz (this is the standard frequency for my country according the OMS annex O document).

Everything is working pretty fine but we are measuring only 90 meters of LOS range. I believe this is very poor.

We are using the W3127 antenna from pulse.

Here is the registers values of the cc1101:

const RF_CONFIG_T tModeRfConfig = {
                                   0x08,   // FSCTRL1   Frequency synthesizer control.
                                   0x00,   // FSCTRL0   Frequency synthesizer control.
                                   0x10,//0x21,   // FREQ2     Frequency control word, high byte.
                                   0xB5,//0x6B,   // FREQ1     Frequency control word, middle byte.
                                   0xE8,//0xD0,   // FREQ0     Frequency control word, low byte.
                                   0x5C,   // MDMCFG4   Modem configuration.  - 103 kBaud
                                   0x04,   // MDMCFG3   Modem configuration.
                                   0x05,   // MDMCFG2   Modem configuration.
                                   0x22,   // MDMCFG1   Modem configuration.
                                   0xF8,   // MDMCFG0   Modem configuration.
                                   0x00,   // CHANNR    Channel number.
                                   0x50,//0x44,   // DEVIATN   Modem deviation setting (when FSK modulation is enabled). -- range improved slightely
                                   0xB6,   // FREND1    Front end RX configuration.
                                   0x10,   // FREND0    Front end RX configuration.
                                   0x18,   // MCSM0     Main Radio Control State Machine configuration.
                                   0x2E,   // FOCCFG    Frequency Offset Compensation Configuration.
                                   0xBF,   // BSCFG     Bit synchronization Configuration.
                                   0x43,   // AGCCTRL2  AGC control.
                                   0x09,   // AGCCTRL1  AGC control.
                                   0xB5,   // AGCCTRL0  AGC control.
                                   0xEA,   // FSCAL3    Frequency synthesizer calibration.
                                   0x2A,   // FSCAL2    Frequency synthesizer calibration.
                                   0x00,   // FSCAL1    Frequency synthesizer calibration.
                                   0x1F,   // FSCAL0    Frequency synthesizer calibration.
                                   0x59,   // FSTEST    Frequency synthesizer calibration.
                                   0x81,   // TEST2     Various test settings.
                                   0x35,   // TEST1     Various test settings.
                                   0x09,   // TEST0     Various test settings.
                                   0x06,   // IOCFG2    GDO2 output pin configuration.
                                   0x00,   // IOCFG0D   GDO0 output pin configuration. Refer to SmartRF® Studio User Manual for detailed pseudo register explanation.
                                   0x00,   // PKTCTRL1  Packet automation control.
                                   0x00,   // PKTCTRL0  Packet automation control.
                                   0x00,   // ADDR      Device address.
                                   0xFF    // PKTLEN    Packet length.
};

const uint8_t tModePaTable[] = {0xC0};

Is there any mistake there or should i review my hardware design (our design is very similar of the 433 MHz ev board)?

  • 0
    TI__Mastermind 36395 points
    Eduardo Bernardi,

    Have you done conductive tests on your system to make sure that it meets with your expectations before going into the field and performing range testing.

    The RF performance of the CC1101 is almost independent of operating frequency across the bands. Therefore you should be able to get close to the values that we measured at 868MHz when measuring the system at 434MHz.

    www.ti.com/.../swra234a.pdf

    The key items to check for are RF output power, TX frequency accuracy (<better than 10ppm) and input sensitivity (values close to what we disclose in the application note).

    Regards,
    /TA