LMiC's TX_COMPLETE event takes 20-30 seconds to fire

[arjanvanb (Arjan)]

@telkamp

LMiC purposely delays the TX_COMPLETE event to prevent the next transmission to collide with a downlink that the node did not receive, but the gateway is still busy sending (and therefor not in receive mode).

It uses a worst-case for that, at SF12 in the RX2 window, that is defined by DNW2_SAFETY_ZONE (in lmic.c) with a default of 3 seconds.

Only now I noticed that since February @matthijs’ LMiC port the event itself is no longer delayed. Nice!

Emit EV_TXCOMPLETE earlier