Hello, I am using libraries available from ST for developing applications based on S2-LP module. I would like to be able to reach a communication distance between 2 devices that is at least 1 KM. I am attaching my current radio configuration. BR

[Mariano Iadaresta]

/* Defines ---------------------------------------------------------------*/

#define XTAL_OFFSET_PPM       0

#define INFINITE_TIMEOUT      0.0

#define BASE_FREQUENCY       868.0e6

#define CHANNEL_SPACE        100e3

#define CHANNEL_NUMBER       0

#define DATARATE          38400

#define FREQ_DEVIATION       20e3

#define BANDWIDTH          100E3

#define POWER_INDEX         7

#define RECEIVE_TIMEOUT       2000.0 /*change the value for required timeout period*/

#define RSSI_THRESHOLD        -120 /* Default RSSI at reception, more

                               than noise floor */

#define CSMA_RSSI_THRESHOLD     -90  /* Higher RSSI to Transmit.

               If it's lower, the Channel will be seen as busy */

/* Packet configuration parameters */

#define SYNC_WORD            0x88888888

#define LENGTH_WIDTH          7

#define CRC_MODE            PKT_CRC_MODE_8BITS

#define EN_FEC             S_DISABLE

#define EN_WHITENING          S_ENABLE

#define MODULATION_SELECT        MOD_2FSK

#define POWER_DBM            16.0

#define PREAMBLE_LENGTH         PREAMBLE_BYTE(4)

#define SYNC_LENGTH           SYNC_BYTE(4)

#define CONTROL_LENGTH         0x00 //PKT_CONTROL_LENGTH_0BYTES

#define VARIABLE_LENGTH         S_ENABLE

#define EXTENDED_LENGTH_FIELD      S_DISABLE

#define PREAMBLE_BYTE(v)        (4*v)

#define SYNC_BYTE(v)          (8*v)

#define VARIABLE_LENGTH         S_ENABLE

#ifndef USE_BASIC_PROTOCOL_ADDRESS

 /* Addresses configuration parameters */

 #define EN_ADDRESS          S_DISABLE

 #define EN_FILT_MY_ADDRESS      S_DISABLE

 #define EN_FILT_MULTICAST_ADDRESS   S_DISABLE

 #define EN_FILT_BROADCAST_ADDRESS   S_DISABLE

 #define EN_FILT_SOURCE_ADDRESS    S_DISABLE//S_ENABLE

 #define SOURCE_ADDR_MASK       0xf0

 #define SOURCE_ADDR_REF        0x37

 #define MULTICAST_ADDRESS       0xEE

 #define BROADCAST_ADDRESS       0xFF

#else

 #define EN_ADDRESS          S_ENABLE

 #define EN_FILT_MY_ADDRESS      S_ENABLE

 #define EN_FILT_MULTICAST_ADDRESS   S_ENABLE

 #define EN_FILT_BROADCAST_ADDRESS   S_ENABLE

 #define EN_FILT_SOURCE_ADDRESS    S_ENABLE

 #define SOURCE_ADDR_MASK       0xf0

 #define SOURCE_ADDR_REF        0x37

 #define MULTICAST_ADDRESS       0xEE

 #define BROADCAST_ADDRESS       0xFF

#endif

#define EN_AUTOACK           S_DISABLE

#define EN_PIGGYBACKING         S_DISABLE

#define MAX_RETRANSMISSIONS       PKT_DISABLE_RETX

#define PAYLOAD_LEN           25 /*20 bytes data + tag + cmd_type + cmd + cmdlen + datalen*/

#define APPLI_CMD            0x11

#define NWK_CMD             0x22

#define LED_TOGGLE           0xff

#define ACK_OK             0x01

#define MAX_BUFFER_LEN         96

#define TIME_TO_EXIT_RX         3000

#define DELAY_RX_LED_TOGGLE       100

#define DELAY_TX_LED_GLOW        100

#define LPM_WAKEUP_TIME         100

#define DATA_SEND_TIME         50

[Javier1]

>>I would like to be able to reach a communication distance between 2 devices that is at least 1 KM.

To improve your link budget:

• Choose directional antennas if you can, also tune them by hand if possible.
• Place good filters in your VCC going to the radio.

Lower the base frecuency as much as possible (if the antenna allows it), ive seen youre in the 868MHZ area, try going down to the 433Mhz zone.(if allowed in your country)

depending of how noisy is your 1Km and whats your acceptable data troughput you could try out other modulations such as ASK

[Mariano Iadaresta]

Dear Javier,

thanks for the reply, i was also wondering if it is worth reducing the bandwidth and baud rate (current 38400). In any case I will do other tests with the changes you suggested and update you.

BR