Messenger attempts to transmit data on it's own

When sitting on a desk indoors my Messenger sometimes drops from a high state of charge (e.g. 97%) to a low state of charge (e.g. 16%) within a few hours. I've noticed this is always accompanied with the "Data Transmitting" arrow appearing on the display. I assume it's wasting power trying to establish communications when it's indoor and can't reach a satellite.

The problem is I never trigger the data transmission.

Does the Messenger periodically send some sort of message without being triggered?

Is there a way to terminate a data transmission once it's started?

I'm running 4.01 SW and tracking is off.

  • The device will automatically check for messages every hour. It will retry until it gets a good connection with the Iridium satellite network and this will drain the battery faster.

    This automatic check cannot be disabled. So best to just turn off the unit when you are inside and not using the Messenger.

  • yes, this is almost a FAQ meanwhile

    some people suggest it should stop all radio activities when not needed. But so far no one could say how the units should notice it. The only way is to try a contact to some of the satellites on the common channel and see if there is some answer.

    simply just listening for any signals does not lead to success, the satellites communicate on different frequencies, even on one satellite there are 48 different beams with different signal channels.

    BTW: when a mobile phone has very weak signal, for example too far from the base tower, it needs also more power the if the communication with the base is easy

  • The Iridium network transmits messages to a particular device only when the device itself ASKS for them. This is what is going on in the hourly "mail check". It's not practical for the network to continuously "spray" all the pending messages addressed to any device. In any case, that's not part of the short message protocol used by iR devices.

    Because Garmin iR devices are intended for backcountry use, possibly in emergencies, the devices try very hard to complete the mail check once started. If you leave the device powered indoors (or in the bottom of your pack overnight, or whatever), the retries will deplete the battery.

    Yes, I know, Messenger has all kinds of non-backcountry, non-emergency uses. But this behavior is common to all iR devices.