The MAJÁK transmitter is a special device for bunker collapse rescue. It delivers about 10W of RF power at 96kHz into a horizontal magnetic loop antenna. At these frequencies, the signal can penetrate meters of soil and can be evaluated (pinpointed) by a rescue squad. The signal is automatically CW keyed to be easy distinguishable from interferring signals.
In the whole set, there is a 12V accumulator and 12V hand-driven charger, thus, the transmission period of the signal is not limited by the capacity of the battery.