GMDSS: Element 3

1. A All Non Directional Beacon (NDB) transmitters are turned-off at dusk and turned-on at dawn.
2. B Non Directional Beacon (NDB) transmissions can bounce-off the Earth's ionosphere at night and be received at almost any direction.
3. C An aircraft's ADF transmissions will be slowed at night due to the increased density of the Earth's atmosphere after sunset.
4. D An aircraft's ADF antennas usually collect dew moisture after sunset which decreases their effective reception distance from an NDB transmitter.

Tip: press A-D to answer