Ham Radio Extra Class Practice Test

JT65 uses multi-tone audio frequency shift keying (AFSK) modulation. This technique employs multiple tones to convey information, utilizing a series of discrete frequencies that represent data bits. Specifically designed for weak signal communication, JT65 is particularly effective in scenarios where signals are faint, as it allows for the transmission of short messages with precise timing.

The use of AFSK in JT65 involves the digital encoding of audio tones, which are then transmitted over radio frequencies. This is advantageous for amateurs seeking to make contacts over long distances or in challenging propagation conditions, as the method is highly resilient against noise and interference.

In contrast, PSK (Phase Shift Keying) involves altering the phase of a carrier wave to encode data, commonly used in other digital modes but not in JT65. RTTY (Radio Teletype) is another form of digital communication but utilizes frequency shift keying rather than multi-tone signaling. IEEE 802.11 refers to a set of standards for wireless networking, not directly related to amateur radio digital modes.