WWV broadcasts universal coordinated time on which frequencies?

WWV broadcasts universal coordinated time on which frequencies?

• A. 1, 2, 3, 4 MHz
• B. 5, 10, 15, 20 MHz
• C. 25, 30, 35, 40 MHz
• D. 40, 60, 80, 100 MHz

Answer: (B)

WWV’s time signal is spread across several shortwave frequencies to ensure worldwide reception. The big idea is that HF propagation depends on time of day and solar activity, so using a range of frequencies gives listeners around the globe a better chance to receive the UTC signal reliably. The four bands used—around five, ten, fifteen, and twenty megahertz—cover a broad portion of the HF spectrum. Higher frequencies tend to work well for long-distance reception during daylight hours when the ionosphere reflects them effectively, while the five-megahertz band remains useful at different times and conditions, including nighttime. By broadcasting on these multiple frequencies, WWV maximizes the probability that a receiver anywhere in the world can pick up the time code clearly, despite local noise or propagation variations. Other frequency sets would either not reach globally with consistent reliability or would be more prone to interference, so they don’t provide the same universal coverage.

WWV’s time signal is spread across several shortwave frequencies to ensure worldwide reception. The big idea is that HF propagation depends on time of day and solar activity, so using a range of frequencies gives listeners around the globe a better chance to receive the UTC signal reliably.

The four bands used—around five, ten, fifteen, and twenty megahertz—cover a broad portion of the HF spectrum. Higher frequencies tend to work well for long-distance reception during daylight hours when the ionosphere reflects them effectively, while the five-megahertz band remains useful at different times and conditions, including nighttime. By broadcasting on these multiple frequencies, WWV maximizes the probability that a receiver anywhere in the world can pick up the time code clearly, despite local noise or propagation variations.

Other frequency sets would either not reach globally with consistent reliability or would be more prone to interference, so they don’t provide the same universal coverage.