Lesson 4: Transceiver Function Check

It is important that all transceivers in a group are checked for proper functioning before starting a trip or task to ensure all units have the capability to send and receive a signal. There are several different transceiver checks.

Battery Test

The battery test should be performed as soon as the transceiver is turned on. The recognized standard for avalanche transceivers requires that the device can still send a signal for a minimum of 24 hours, and perform in search mode for a minimum of two hours, even at 0% indicated battery strength. The search function uses considerably more power, so it is important to have a good power reserve in case a long search is required. When choosing batteries for your transceiver, consider the following:

  • Follow the manufacturer’s recommendation for type and quality.
  • Poor-quality batters and improper storage are the most common reasons for device failure.
  • Never use rechargeable batteries in a transceiver.
  • When replacing batteries, change all batteries at the same time.
  • Some devices will accept lithium batters as per the manufacture’s guidelines. Lithium batteries last longer in extremely cold temperatures, however have a flat discharge curve, meaning that the battery indicator will rapidly jump from 100% to 0%.
  • During any battery charge, it is important to check the battery contacts on the device for any sign of corrosion. Any visible corrosion on the contacts requires the device to be sent to a service centre for repairs.

Full Function Check

A full function check can be performed quickly and has the benefit of ensuring all transceivers are properly functioning in transmit and receive modes. It should be performed at the start of each trip or operation. For multi-day trips with the same group, the full function check does not need to be performed daily.

Procedure:

  1. Choose a safe location away from interference.
  2. The leader directs all group members to bring out their transceivers and switch them to receive mode while the leader remains on transmit.
  3. When the leader confirms everyone is receiving only one signal, the leader moves away from the group. Each member monitors the distance indication and indicates by raising a hand when their transceiver is no longer able to receive the signal. This exercise gives the receive range for each transceiver in the group.
  4. The group members then switch back to transmit, and store their transceivers as the leader switches to receive.
  5. The leader has each member move past him one at a time so that the transmit range of each transceiver can be confirmed. Each group member must be spaced 15 meters apart.
  6. The leader then switches his transceiver back to transmit.

Transmit Check

Checking the transmit function is critical because it confirms that each transceiver is switched on and transmitting a signal. It is performed daily, and should be repeated when necessary (e.g. after a search exercise, change of clothing, new members joining a group, or any situation when the transceiver may have been turned off).

The procedure for a transmit check depends on the type of transceiver and whether or not it has a group-check mode. This special mode checks for full output strength of the signal at close range and is equivalent to a full function check.

Procedure for transceiver with a group-check mode:

  1. The leader switches into group-check mode.
  2. The leader checks each group member one at a time by moving within the specified range. Each group member must be spaced far enough apart to avoid interference (1-2 meters).
  3. The leader switches his or her transceiver to transmit.

Procedure for transceiver without a group-check mode:

  1. The leader moves away from the group at least 30 meters and turns his transceiver to receive mode.
  2. Group members keep their devices on transmit mode.
  3. Each group member moves by the leader, spaced 15 meters apart to minimize confusion from multiple signals, and the leader ensures that each transceiver is working properly and transmitting a signal.
  4. The last member then checks the leader’s transmit function.