Poor range with a The Things Network and Feather M0

Hello,

I’m testing an Adafruit Feather M0 with a 915 Mhz The Things Gateway.

I am able to receive messages OK from the M0, but my range only seems to be about 2000 ft / 600 m.

For the antenna on the M0, I used a wire that I already had, I cut to a 3 inch / 7.6 cm length:

IMG_20180517_161754408

I’m suspecting the antenna on the M0 might be the problem, does anyone know what would be the best antenna choice?

Here is the code on the M0:

indent preformatted text by 4 spaces
/******************************************************************************* 
* Copyright (c) 2015 Thomas Telkamp and Matthijs Kooijman 
* 
* Permission is hereby granted, free of charge, to anyone 
* obtaining a copy of this document and accompanying files, 
* to do whatever they want with them without any restriction, 
* including, but not limited to, copying, modification and redistribution. 
* NO WARRANTY OF ANY KIND IS PROVIDED. 
* 
* This example sends a valid LoRaWAN packet with payload "Hello, 
* world!", using frequency and encryption settings matching those of 
* the The Things Network. 
* 
* This uses ABP (Activation-by-personalisation), where a DevAddr and 
* Session keys are preconfigured (unlike OTAA, where a DevEUI and 
* application key is configured, while the DevAddr and session keys are 
* assigned/generated in the over-the-air-activation procedure). 
* 
* Note: LoRaWAN per sub-band duty-cycle limitation is enforced (1% in 
* g1, 0.1% in g2), but not the TTN fair usage policy (which is probably 
* violated by this sketch when left running for longer)! 
* 
* To use this sketch, first register your application and device with 
* the things network, to set or generate a DevAddr, NwkSKey and 
* AppSKey. Each device should have their own unique values for these 
* fields. 
* 
* Do not forget to define the radio type correctly in config.h. 
* 
*******************************************************************************/ 
  
//Probably need to change Serial11 to Serial111 
  
#include <lmic.h> 
#include <hal/hal.h> 
#include <SPI.h> 
#include <avr/dtostrf.h> 
  
// LoRaWAN NwkSKey, network session key 
// This is the default Semtech key, which is used by the early prototype TTN 
// network. 
static const PROGMEM u1_t NWKSKEY[16] = { 0x**, 0x**, 0x**, 0x**, 0x**, 0x**, 0x**, 0x**, 0x**, 0x**, 0x**, 0x**, 0x**, 0x**, 0x**, 0x** }; 
  
// LoRaWAN AppSKey, application session key 
// This is the default Semtech key, which is used by the early prototype TTN 
// network. 
static const u1_t PROGMEM APPSKEY[16] = { 0x**, 0x**, 0x**, 0x**, 0x**, 0x**, 0x**, 0x**, 0x**, 0x**, 0x**, 0x**, 0x**, 0x**, 0x**, 0x** }; 
  
// LoRaWAN end-device address (DevAddr) 
static const u4_t DEVADDR = 0x******** ; // <-- Change this address for every node! 
  
// These callbacks are only used in over-the-air activation, so they are 
// left empty here (we cannot leave them out completely unless 
// DISABLE_JOIN is set in config.h, otherwise the linker will complain). 
void os_getArtEui (u1_t* buf) { } 
void os_getDevEui (u1_t* buf) { } 
void os_getDevKey (u1_t* buf) { } 
  
static uint8_t mydata[] = "Hello, world!"; 
static osjob_t sendjob; 
  
// Schedule TX every this many seconds (might become longer due to duty 
// cycle limitations). 
const unsigned TX_INTERVAL = 60; 
  
// Pin mapping 
/*const lmic_pinmap lmic_pins = { 
    .nss = 6, 
    .rxtx = LMIC_UNUSED_PIN, 
    .rst = 5, 
    .dio = {2, 3, 4}, 
*/ 
/*const lmic_pinmap lmic_pins = { 
    .nss = 8, 
    .rxtx = LMIC_UNUSED_PIN, 
    .rst = 4, 
    .dio = {7, 6, LMIC_UNUSED_PIN}, 
    */ 
const lmic_pinmap lmic_pins = { 
    .nss = 8, 
    .rxtx = LMIC_UNUSED_PIN, 
    .rst = LMIC_UNUSED_PIN, 
    .dio = {3, 6, LMIC_UNUSED_PIN}, 
}; 
  
/* #if defined(ARDUINO_SAMD_ZERO) && defined(SERIAL_PORT_USBVIRTUAL) 
  // Required for Serial on Zero based boards 
  #define Serial SERIAL_PORT_USBVIRTUAL 
#endif 
*/  
  
void onEvent (ev_t ev) { 
    Serial.print(os_getTime()); 
    Serial.print(": "); 
    switch(ev) { 
        case EV_SCAN_TIMEOUT: 
            Serial.println(F("EV_SCAN_TIMEOUT")); 
            break; 
        case EV_BEACON_FOUND: 
            Serial.println(F("EV_BEACON_FOUND")); 
            break; 
        case EV_BEACON_MISSED: 
            Serial.println(F("EV_BEACON_MISSED")); 
            break; 
        case EV_BEACON_TRACKED: 
            Serial.println(F("EV_BEACON_TRACKED")); 
            break; 
        case EV_JOINING: 
            Serial.println(F("EV_JOINING")); 
            break; 
        case EV_JOINED: 
            Serial.println(F("EV_JOINED")); 
            break; 
        case EV_RFU1: 
            Serial.println(F("EV_RFU1")); 
            break; 
        case EV_JOIN_FAILED: 
            Serial.println(F("EV_JOIN_FAILED")); 
            break; 
        case EV_REJOIN_FAILED: 
            Serial.println(F("EV_REJOIN_FAILED")); 
            break; 
        case EV_TXCOMPLETE: 
            Serial.println(F("EV_TXCOMPLETE (includes waiting for RX windows)")); 
            if (LMIC.txrxFlags & TXRX_ACK) 
              Serial.println(F("Received ack")); 
            if (LMIC.dataLen) { 
              Serial.println(F("Received ")); 
              Serial.println(LMIC.dataLen); 
              Serial.println(F(" bytes of payload")); 
            } 
            // Schedule next transmission 
            os_setTimedCallback(&sendjob, os_getTime()+sec2osticks(TX_INTERVAL), do_send); 
            break; 
        case EV_LOST_TSYNC: 
            Serial.println(F("EV_LOST_TSYNC")); 
            break; 
        case EV_RESET: 
            Serial.println(F("EV_RESET")); 
            break; 
        case EV_RXCOMPLETE: 
            // data received in ping slot 
            Serial.println(F("EV_RXCOMPLETE")); 
            break; 
        case EV_LINK_DEAD: 
            Serial.println(F("EV_LINK_DEAD")); 
            break; 
        case EV_LINK_ALIVE: 
            Serial.println(F("EV_LINK_ALIVE")); 
            break; 
         default: 
            Serial.println(F("Unknown event")); 
            break; 
    } 
} 
  
void do_send(osjob_t* j){ 
    Serial.println("do_send called"); 
    // Check if there is not a current TX/RX job running 
    if (LMIC.opmode & OP_TXRXPEND) { 
        Serial.println(F("OP_TXRXPEND, not sending")); 
    } else { 
        // Prepare upstream data transmission at the next possible time. 
        LMIC_setTxData2(1, mydata, sizeof(mydata)-1, 0); 
        Serial.println(F("Packet queued")); 
    } 
    // Next TX is scheduled after TX_COMPLETE event. 
} 
      
void setup() { 
    Serial.println("setup called"); 
    Serial.begin(115200); 
    Serial.println(F("Starting")); 
  
    #ifdef VCC_ENABLE 
    // For Pinoccio Scout boards 
    pinMode(VCC_ENABLE, OUTPUT); 
    digitalWrite(VCC_ENABLE, HIGH); 
    delay(1000); 
    #endif 
  
    // LMIC init 
    os_init(); 
    // Reset the MAC state. Session and pending data transfers will be discarded. 
    LMIC_reset(); 
  
    // Set static session parameters. Instead of dynamically establishing a session 
    // by joining the network, precomputed session parameters are be provided. 
    #ifdef PROGMEM 
    // On AVR, these values are stored in flash and only copied to RAM 
    // once. Copy them to a temporary buffer here, LMIC_setSession will 
    // copy them into a buffer of its own again. 
    uint8_t appskey[sizeof(APPSKEY)]; 
    uint8_t nwkskey[sizeof(NWKSKEY)]; 
    memcpy_P(appskey, APPSKEY, sizeof(APPSKEY)); 
    memcpy_P(nwkskey, NWKSKEY, sizeof(NWKSKEY)); 
    LMIC_setSession (0x1, DEVADDR, nwkskey, appskey); 
    #else 
    // If not running an AVR with PROGMEM, just use the arrays directly 
    LMIC_setSession (0x1, DEVADDR, NWKSKEY, APPSKEY); 
    #endif 
  
    #if defined(CFG_eu868) 
    // Set up the channels used by the Things Network, which corresponds 
    // to the defaults of most gateways. Without this, only three base 
    // channels from the LoRaWAN specification are used, which certainly 
    // works, so it is good for debugging, but can overload those 
    // frequencies, so be sure to configure the full frequency range of 
    // your network here (unless your network autoconfigures them). 
    // Setting up channels should happen after LMIC_setSession, as that 
    // configures the minimal channel set. 
    // NA-US channels 0-71 are configured automatically 
    LMIC_setupChannel(0, 868100000, DR_RANGE_MAP(DR_SF12, DR_SF7),  BAND_CENTI);      // g-band 
    LMIC_setupChannel(1, 868300000, DR_RANGE_MAP(DR_SF12, DR_SF7B), BAND_CENTI);      // g-band 
    LMIC_setupChannel(2, 868500000, DR_RANGE_MAP(DR_SF12, DR_SF7),  BAND_CENTI);      // g-band 
    LMIC_setupChannel(3, 867100000, DR_RANGE_MAP(DR_SF12, DR_SF7),  BAND_CENTI);      // g-band 
    LMIC_setupChannel(4, 867300000, DR_RANGE_MAP(DR_SF12, DR_SF7),  BAND_CENTI);      // g-band 
    LMIC_setupChannel(5, 867500000, DR_RANGE_MAP(DR_SF12, DR_SF7),  BAND_CENTI);      // g-band 
    LMIC_setupChannel(6, 867700000, DR_RANGE_MAP(DR_SF12, DR_SF7),  BAND_CENTI);      // g-band 
    LMIC_setupChannel(7, 867900000, DR_RANGE_MAP(DR_SF12, DR_SF7),  BAND_CENTI);      // g-band 
    LMIC_setupChannel(8, 868800000, DR_RANGE_MAP(DR_FSK,  DR_FSK),  BAND_MILLI);      // g2-band 
    // TTN defines an additional channel at 869.525Mhz using SF9 for class B 
    // devices' ping slots. LMIC does not have an easy way to define set this 
    // frequency and support for class B is spotty and untested, so this 
    // frequency is not configured here. 
    #elif defined(CFG_us915) 
    // NA-US channels 0-71 are configured automatically 
    // but only one group of 8 should (a subband) should be active 
    // TTN recommends the second sub band, 1 in a zero based count. 
    // https://github.com/TheThingsNetwork/gateway-conf/blob/master/US-global_conf.json 
    LMIC_selectSubBand(1); 
    #endif 
  
    // Disable link check validation 
    LMIC_setLinkCheckMode(0); 
  
    // TTN uses SF9 for its RX2 window. 
    LMIC.dn2Dr = DR_SF9; 
  
    // Set data rate and transmit power for uplink (note: txpow seems to be ignored by the library) 
    LMIC_setDrTxpow(DR_SF7,14); 
  
    // Start job 
    do_send(&sendjob); 
} 
  
void loop() { 
  Serial.println("loop called"); 
  digitalWrite(LED_BUILTIN, HIGH);   // turn the LED on (HIGH is the voltage level) 
  delay(6000);                       // wait for a second 
  digitalWrite(LED_BUILTIN, LOW);    // turn the LED off by making the voltage LOW 
  delay(4000);   
  os_runloop_once(); 
}

There really is no such thing as a ‘best’ antenna.

There are better antennas than the simple 1/4 wire you have, a dipole for instance and that would overcome some of the loss of efficiency if you dont counterpoise the 1/4wave wire with an effective antenna.

Better antennas tend to be bigger, more directional and cost more too.

Range depends on SF, landform, antenna, tx power, etc.
If you want to increase range rapidly, the simplest way is to increase SF and tx power.

Ok.

Has anyone been able to receive messages from a node more than 500 meters away in an urban environment?

If so, what node hardware, SF, TX power?

Has anyone been able to receive messages from a node more than 500 meters away in an urban environment?

You got 600M.

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