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Sending a Range Command

After successfully sending a ping, try sending a range command. In this example, change the software transmit-power setting.

At the initiating modem's pshell prompt, enter:

range <transmit-power-setting> (for this example, use 4)

(for this example, use 4)

This command results in the following sequence:

  1. Modem A sends a range request using transmit-power setting 4 on the software scale.
  2. Modem A's red transmit LED illuminates for approximately one second.
  3. Modem B receives and demodulates the request, then schedules a transmission back to Modem A.
  4. Modem B's red transmit LED illuminates during this response.
  5. When Modem A receives the response, it accounts for the turnaround time and calculates the round-trip travel time. The modem converts this time to a distance using the speed of sound in water.
  6. After the ranging cycle completes successfully, Modem A displays a range report in pshell.
Air ranging accuracy

Because the calculation uses the speed of sound in water, a range measured during an air test is not an accurate physical distance.