LOW-FREQUENCY COMMUNICATIONS

URR-R389. Figure 2-3 illustrates a typical vlf receiving system, using the AN/BRR-3 receiver. Most surface ships no longer receive vlf broadcasts. However, you will probably find one of these receivers mounted somewhere in your message center or radio room. LOW-FREQUENCY COMMUNICATIONS The low-frequency (lf) band occupies a very small portion of the radio frequency spectrum. However, the Navy’s requirement to provide the best possible communications to the fleet requires operation on all frequency bands. The low-frequency band is used for long-range direction finding, encrypted medium- and long-range communications, and aeronautical radio navigation. Lf Transmit The low-frequency transmitter is a part of the Fleet Multichannel Broadcast System, operating at high Figure 2-3.—Typical vlf receiving system. 2 - 4