1. ELTs transmit simultaneously on 121.5 and 243.0 megahertz.
a. You can monitor either frequency during flight and before shutdown (after landing) to ensure your ELT has not been activated.

2. The VHF/Direction Finder facility is a ground operation that displays the magnetic direction of the airplane from the station each time the airplane transmits a signal to it.

3. In order to take advantage of VHF/DF radio reception for assistance in locating a position, an airplane must have both a VHF transmitter and a receiver. The transmitter and receiver are necessary to converse with a ground station having VHF/DF facilities.
a. The transmitter is also needed to send the signal that the Direction Finder identifies in terms of magnetic heading from the facility.