How many frequencies are available for JTIDS transmissions?

• A. 40
• B. 51
• C. 60
• D. 72

Answer: (B)

JTIDS uses a frequency-hopped spread-spectrum approach, meaning transmissions jump among a fixed pool of carrier frequencies. The number defined for JTIDS transmissions is 51 discrete frequencies. This pool is shared by all participants in a network, and the hopping sequence is coordinated so that communicators land on the same frequency at the right times, enabling reliable communication while providing strong anti-jam and interference rejection. The other counts don’t match the standard JTIDS frequency plan, which is why 51 is the correct pool size.