The best frequency to use for long distance radio communication at night depends on several factors, including the location of the transmitter and receiver, atmospheric conditions, and the time of year. Generally, for long-distance radio communication at night, the lower frequency bands tend to work better than the higher frequency bands. This is because lower frequency signals are less affected by ionospheric disturbances, which can cause signal attenuation and distortion.
One of the most commonly used frequency bands for long distance radio communication at night is the 3 to 30 MHz High Frequency (HF) band. Within this band, the lower frequencies such as 3.5 MHz (80 meters) and 7 MHz (40 meters) are often used for long-distance communication at night, especially for amateur radio operators. The 1.8 MHz (160 meters) band is also used for long-distance communication at night but requires a larger antenna.
It is important to note that radio communication at night can be affected by various factors, such as solar activity, atmospheric noise, and interference from man-made sources. Therefore, it is recommended to consult with frequency allocation charts and use propagation prediction tools to determine the best frequency to use for long distance radio communication at night.
Day time
The best time of the day to make long distance radio contacts depends on several factors, including the location of the transmitter and receiver, atmospheric conditions, and the frequency being used. Generally, radio communication is better during daylight hours when the ionosphere is ionized by the sun, allowing radio waves to travel further distances.
For frequencies below 30 MHz, radio communication is often better during the daytime because the ionosphere is more stable and allows radio waves to propagate over longer distances. However, radio communication can also be good during the night on lower frequencies, especially on the 160 and 80-meter bands, as the ionosphere can still reflect the signals at night.
For frequencies above 30 MHz, radio communication is generally better during the night when the ionosphere is less ionized and has less absorption of the radio waves. The higher frequency bands such as VHF and UHF are often used for short-distance communication during the day, while the lower frequency bands such as HF and VLF are often used for long-distance communication during the day and night.
It is important to note that radio communication is affected by various factors such as solar activity, atmospheric noise, and interference from man-made sources. Therefore, it is recommended to consult with frequency allocation charts and use propagation prediction tools to determine the best time of day and frequency to use for long distance radio contacts.