Survey Sweep

In Survey Sweep Mode, connectivity with the gateway is tested over a range of power levels and data rates. Sweeps are assigned a sweep index so they can be referenced later. 

The survey results of all surveys in a sweep, whether they passed or failed, are saved to a data file on the device but only successful surveys are transmitted to the gateway. See Survey Data File for data format.

The user can configure the minimum and maximum data rates and power levels to use for sweeps using Configuration Mode. The defaults are listed below:

  • Minimum Data Rate SF7
  • Maximum Data Rate SF10 in 915 Frequency Band, SF12 in 868 Frequency Band
  • Minimum Power 2 dBm
  • Maximum Power 20 dBm

A Survey Sweep using the default settings tests connectivity for each of the following data rate/power combinations.

915 Frequency Band (US) 868 Frequency Band (Europe)
Spreading Factor 7, 2 dBm Spreading Factor 7, 2 dBm
Spreading Factor 7, 8 dBm Spreading Factor 7, 8 dBm
Spreading Factor 7, 14 dBm Spreading Factor 7, 14 dBm
Spreading Factor 7, 20 dBm Spreading Factor 7, 20 dBm
Spreading Factor 8, 2 dBm Spreading Factor 8, 2 dBm
Spreading Factor 8, 8 dBm Spreading Factor 8, 8 dBm
Spreading Factor 8, 14 dBm Spreading Factor 8, 14 dBm
Spreading Factor 8, 20 dBm Spreading Factor 8, 20 dBm
Spreading Factor 9, 2 dBm Spreading Factor 9, 2 dBm
Spreading Factor 9, 8 dBm Spreading Factor 9, 8 dBm
Spreading Factor 9, 14 dBm Spreading Factor 9, 14 dBm
Spreading Factor 9, 20 dBm Spreading Factor 9, 20 dBm
Spreading Factor 10, 2 dBm Spreading Factor 10, 2 dBm
Spreading Factor 10, 8 dBm Spreading Factor 10, 8 dBm
Spreading Factor 10, 14 dBm Spreading Factor 10, 14 dBm
Spreading Factor 10, 20 dBm Spreading Factor 10, 20 dBm
  Spreading Factor 11 , 2 dBm
  Spreading Factor 11, 8 dBm
  Spreading Factor 11, 14 dBm
  Spreading Factor 11, 20 dBm
  Spreading Factor 12, 2 dBm
  Spreading Factor 12, 8 dBm
  Spreading Factor 12, 14 dBm
  Spreading Factor 12, 20 dBm

If settings are not at their default values, Survey Sweep Mode chooses four power levels evenly spaced through the configured range. If there are four or fewer power levels in the range, every power level in the range is used.

To execute a Survey Sweep:

  1. From the main menu, press SW1 (Select) when -> is on Survey Sweep.
  2. If a Survey Data File exists, choose either SW2 (Erase) or SW1 (Append) to the current file. 
  3. Then press SW2(Sweep) to initiate the sweep. Between surveys in the sweep, the user can press SW1(Cancel) to stop the remainder of the sweep.  For each successful survey in the sweep, the following information is shown on the screen:
    • the sweep index
    • the TX data rate and power
    • the upstream margin above the demodulation or the downstream RSSI and SNR
    • the GPS longitude, if available
    • the GPS latitude, if available
    • the GPS time and date (UTC format), if available

    If the survey was successful and data packet transmission to the gateway has been enabled with the +DATA configuration command, the device displays following data:

        • the TX power
        • the number of gateways which received the link check request
        • the upstream margin above the demodulation or the downstream RSSI and SNR

    If the data rate allows for a large enough payload, GPS information is sent to the gateway:

        • the GPS lock status
        • the GPS longitude
        • the GPS latitude
        • the GPS altitude
        • the GPS timestamp (UTC format)

    Note: With the 915 MHz frequency band, data rate 10 only allows for an 11 byte payload, which is too small to include GPS data. All other data rates allow for a large enough payload to include GPS data.
    If a survey is unsuccessful, the following information is displayed on the screen:

        • the sweep index
        • the TX data rate and power
        • the GPS longitude, if available
        • the GPS latitude, if available
        • the GPS time and date (UTC format), if available
        • the GPS timestamp (UTC format)

When the entire sweep is finished or has been cancelled, the following information is displayed on the screen:

  • the sweep index
  • the number of successful surveys in the sweep
  • the number of unsuccessful surveys in the sweep