The TACAN System operates in the UHF band and has

• A. 64 channels
• B. 126 channels
• C. 252 channels
• D. 512 channels

Answer: (B)

TACAN uses a fixed set of discrete channels in the UHF navigation band to provide both azimuth bearing and distance information. The channel count you tune to is the number of distinct channels available for interrogations, and in standard TACAN operation pilots select from 126 channels. Each channel corresponds to a specific pair of frequencies used for the interrogation and reply, enabling the distance (range) measurement, while the azimuth is determined by the TACAN’s rotating or patterned antenna to give bearing.

The number 126 is the conventional tally of usable TACAN channels. Some texts mention 252 subchannels because each channel can be used in two modulation modes (X and Y), but the practical, selectable channel count for TACAN navigation is 126. The other options (64, 252, 512) do not match the standard TACAN channel set used in aviation navigation.