SmartBeacon

[Freakwave3]

Hi all,
can anyone explain the SmartBeacon settings (e.g. max/min Interval) please?

[tom-acco]

I put this together so you can play with some settings and see the results. The "old method" is the method used by this repo.

https://tom-acco.github.io/aprs-smart-beacon-calculator/

Basically:
If the speed is greater than the fast speed, interval will be the max interval.
If the speed is less than the slow speed, interval will be the slow interval.
If the speed is between, slow and fast, then the following maths equation is applied:
(15 * fast speed) / speed

The interval is then adjusted further:
If the interval is less than 5, set it to 5
If the interval is greater than the max interval, set it to the max interval
Then some funky stuff about if the heading changes, set the interval to the min interval

void smartbeacon(void)
{
  // Adaptive beacon rate
  if (SB_SPEED >= config.trk_hspeed)
  {
    tx_interval = (uint16_t)config.trk_maxinterval;
  }
  else
  {
    if (SB_SPEED <= config.trk_lspeed)
    {
      // Speed is below lower limit - use minimum rate
      tx_interval = (uint16_t)config.trk_slowinterval;
    }
    else
    {
      // In between, do SmartBeaconing calculations
      if (SB_SPEED <= 0)
        SB_SPEED = 1;
      tx_interval = (trk_interval * config.trk_hspeed) / SB_SPEED;
      if (tx_interval < 5)
        tx_interval = 5;
      if (tx_interval > config.trk_maxinterval)
        tx_interval = (uint16_t)config.trk_maxinterval;

      // Corner pegging - note that we use two-degree units
      if (last_heading > SB_HEADING)
        heading_change = last_heading - SB_HEADING;
      else
        heading_change = SB_HEADING - last_heading;
      if (heading_change > 90)
        heading_change = 180 - heading_change;
      if (heading_change > config.trk_minangle)
      {
        // Make sure last heading is updated during turns to avoid immedate xmit
        if (tx_counter > config.trk_mininterval)
        {
          EVENT_TX_POSITION = 3;
        }
        else
        {
          // last_heading = SB_HEADING;
          tx_interval = config.trk_mininterval;
        }
      }
    }
  }
}