Downlink testing: TX interval

[Praneethsvch]

Changing duty cycle using TX_INTERVAL as a variable:

• testing different duty cycles
• does accidental downlink of large numbers have a danger of sleeping the mcu indefinetly?
• downlink is only changed after an uplink. The following code will print out the downlink received in one of the RX windows.

if (LMIC.dataLen) 
{
      // data received in rx slot after tx
      Serial.print(F("Received "));
      Serial.print(LMIC.dataLen);
      Serial.print(F(" bytes of payload: 0x"));
      for (int i = 0; i < LMIC.dataLen; i++) {
         if (LMIC.frame[LMIC.dataBeg + i] < 0x10) {
              Serial.print(F("0"));
           }
         Serial.print(LMIC.frame[LMIC.dataBeg + i], HEX);
       }
      Serial.println();
      receive_downlink();
}

• using node red to send the downlinks

[Praneethsvch]

Queuing Multiple downlinks issue can be solved by using 'replace' option. The downlink will replace the currently scheduled downlink, if any. It is also possible to schedule the downlink as the first or last item in a the downlink queue : reference

[Praneethsvch]

Using node-red to inject custom downlinks:

Sample Flow:

The Inject blocks are manual switches to change the downlink payload message. Using String option and sending bytes in Hexadecimal format.
Inject block:

Using 'replace' as scheduling option to prevent Multiple downlinks Queuing issue
downlink node:

[Praneethsvch]

TTN fair access policy allows a maximum of 10 downlinks, including the ACKs for confirmed uplinks. Exceeding this limit: Can I avoid Fair Access Policy by implementing a private TTN network?