Why is listening to short-wave radio clearer at night than in the morning?

1. Why do you receive more short-wave radio stations at night than during the day?

The way of short-wave propagation mainly depends on ground waves, and only a small part of it propagates in the form of antennas. When a radio wave touches a conductor, it will induce a current in the conductor, thus losing some energy. This phenomenon of weakening radio wave energy is called radio wave absorption. The earth is a conductor, and it absorbs short waves very strongly, so short waves propagating in the form of ground waves will not travel very far (about two or three hundred kilometers). During the day, due to sunlight, the density of the ionosphere increases, making the ionosphere a good conductor. A small part of short waves propagating in the form of sky waves are strongly absorbed when entering the ionosphere, and it is difficult to return to the ground. In addition, the short wave in the form of ground wave is absorbed by the earth, and the propagation distance is not long, which makes it difficult to receive distant short wave radio stations during the day. At night, the atmosphere is no longer exposed to sunlight, and the electrons and ions in the ionosphere recombine with each other and increase significantly, so the ionosphere becomes thinner, the density becomes smaller, the conductivity becomes worse, and the absorption of radio waves is greatly weakened. At this time, short waves can travel far away through sky waves. Therefore, more short-wave radio stations are received at night.

2. Why is shortwave radio's voice sometimes loud and sometimes small?

Short-wave radio waves mainly rely on the back-and-forth reflection and refraction between the ionosphere and the ground. No matter day or night, short waves can travel far, so the short-wave band of the radio can receive long-distance radio sounds. However, the ionosphere is unstable, and its thickness, height and ionospheric density are changing at any time, especially during the day, when the short-wave signal reaches the radio, it is strong and weak. So when listening to short-wave radio, the sound is big and small. Radio with better automatic gain control (AGC) performance can alleviate this phenomenon.

3. Is the short wave signal clear?

The effect of listening to short-wave broadcasting depends on environmental factors such as radio transmission power, radio performance and receiving location. With the improvement of radio technology, the listening effect will be better and better. The effect of short-wave programs listened to at different times of the day: the propagation of short-wave signals is influenced by many factors, such as sunspot activity, changes in the atmosphere and the ionosphere of the earth, and not all short-wave propagation effects are good. Some are good during the day and some are good at night. Usually, the effect of receiving short-wave programs during the day is not very good, especially 10 from early morning to 3 pm. The main reason is that during this period, short-wave radio waves are greatly influenced by ionospheric changes and have a short propagation distance. If you want to receive short-wave programs during the day, it may be better to receive them within a few meters, but you can't receive them at night.

4. Where can the shortwave radio station receive the broadcast?

Most countries in the world have short-wave broadcasting, but short-wave radio stations in some small countries can only cover the whole country because of their low transmission power, and the listening effect in China is not good. No matter how powerful a radio station is, it depends on whether your geographical position is within its coverage. For example, some frequencies of short-wave broadcasting in china national radio, China are well received in Northeast China, but not in Southwest China.

5. Do you need an outdoor external antenna to listen to short-wave broadcasting?

It depends on your listening environment. Houses with reinforced structures will block broadcast signals, and short-wave signals in some remote areas, mountainous areas and mining areas will be weaker, so outdoor antennas need to be installed.