Which of the following bands may provide long-distance communications via the ionosphere’s F region during the peak of the sunspot cycle?
6 and 10 meters✓Bonne réponse
23 centimeters
70 centimeters and 1.25 meters
All these choices are correct
Explication
At the peak of the sunspot cycle the maximum usable frequency can rise above 50 MHz, so 10 metres and sometimes 6 metres open for long-distance F region contacts. The UHF and microwave bands stay far above any achievable maximum usable frequency.