What is the international shortwave broadcasting used outside the meter band?
what is shortwave radio? Many countries in the world use short-wave frequency for worldwide broadcast transmission. The short-wave frequency range is usually between 1.6 MHz and 3 MHz, and the radio that can receive the above-mentioned frequency is called shortwave radio.
what is "short wave meter band"? Generally, we also divide the short-wave frequency into many "meter waves", and each meter band contains a frequency range.
for example, the 19M-meter band contains frequencies ranging from 15.1 to 15.6MHz. The International Radio Commission stipulates that civil broadcasting uses frequencies within the meter band, while frequencies outside the meter band are mostly used for military and other civil communications. Therefore, only in the meter band frequency range can we receive the programs of civil radio stations. (Please refer to the following short-wave meter band division table)
Effects of short-wave programs listened to at different times of the day: The propagation of short-wave signals is affected by many factors, such as sunspot activity, changes in the atmosphere and the earth's ionosphere, and not all short-wave propagation effects are good. Some are good during the day and some are good at night. Usually listening to short-wave programs during the day is not very effective, especially from 1 am to 3 pm. The main reason is that during this period, short-wave radio waves are greatly influenced by the change of ionosphere and have a short propagation distance. If you want to listen to short-wave programs during the day, please refer to Table 2. Maybe the reception effect will be better in some rice bands, but it can't achieve the effect of listening at night.
Short-wave meter band division table
Description of meter band megahertz kilohertz band radio reception
11 25.67-26.1 2567-261 international band radio stations are rare
13 21.45-21.85 2145-2185 international band.
15 18.9-19.2 189-192 There are many international band radio stations, preferably from noon to before 9: pm, with average effect in the morning and morning, and few radio stations from late night to morning.
16 17.48-17.9 1748-179 international band
19 15.1-15.8 151-158 international band
21 or 22 13.57-13.87 1357-1387 international band in the evening.
25 11.6-12.1 116-121 international band radio stations are the most, and they are good all day, especially in the morning, morning and evening before 12 o'clock.
p>31 9.4-- 9.9 94--99 international band
p>41 7.1-- 7.35 71--735 there are many international band radio stations, and many radio stations are received in the morning, evening and late at night,
but they are easily disturbed and noisy.
p>49 5.9-- 6.2 59--62 international band
p>6 4.75-- 5.6 475--56 regional band
p>75 3.9-- 4. 39--4 international band has a good effect at night, but there are not many radio stations, and the effect is poor during the day.
p>9 3.2-- 3.4 32--34 regional band
p>12 2.3-- 2.495 23--2495 regional band
Note: 1 MHz (megahertz) equals 1KHz (kilohertz)
● The reception effect is slightly different due to the seasons. Even a powerful radio station depends on whether your geographical location 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.
What languages can shortwave radio listen to? The languages often heard in short-wave radio programs are Mandarin Chinese, English, French, German, Russian, Japanese, Hindi, Spanish, Portuguese and so on, as well as dialects such as Cantonese, Chaoshan, Shanghainese and Minnan in China, and Mongolian, Uygur, Tibetan, Kazakh and Korean in china national radio in China.
What are the contents of short-wave programs? Due to the influence of national culture and political background in different countries, the contents of short-wave broadcasts vary from country to country. Generally speaking, international short-wave broadcasting programs include world news, domestic news and local news, news commentary, national culture, music appreciation, language teaching, etc. Some countries also offer programs such as police information announcement, weather forecast and marine information forecast. It must be emphasized that the official radio stations of all governments represent their own political positions and economic interests. Therefore, when listening to international broadcasts, they should have certain resolution.
Is the short-wave signal clear? The effect of listening to short-wave broadcasting depends on environmental factors such as the strength of radio transmission power, the performance of radio and the receiving place. With the improvement of radio technology, the listening effect will be better and better.
Do you need an external antenna to listen to short-wave broadcasting? It depends on your listening environment. Houses with reinforced structures will block broadcasting signals, and some remote areas, mountainous areas and mining areas will have weaker short-wave signals, so it is necessary to install an outdoor antenna.
How to test the effect of external antenna: In general listening environment, tune the radio to a weak short-wave radio station and go out while listening. If the signal of this short-wave radio station is enhanced, an outdoor antenna should be installed to improve the receiving effect. However, if there are powerful radio communication transmitting antennas such as TV stations, FM stations and BB machines near the receiving place, strong interference signals may make the receiving effect of short-wave external antennas worse.
Does the external antenna have to be very high and long? Simply put, the effect will be better if the short-wave external antenna is higher and longer, but the higher the antenna, the longer the better. Sometimes, too sensitive antenna will introduce strong radio interference clutter. Therefore, we should adjust the height and length of the external antenna according to our actual needs. Special warning: Never install an outdoor external antenna in a thunderous area!
Why does the sound of short-wave radio sometimes fluctuate greatly? Short-wave radio waves mainly rely on the back and forth reflection and refraction between the ionosphere and the ground. Short-wave can travel far, no matter day or night, so the short-wave band of the radio can hear the long-distance radio sound. However, the ionosphere is unstable, and its thickness, height and ionospheric density are changing at any time, especially during the day, and the short-wave signals reaching the radio are sometimes strong and sometimes weak. Therefore, when listening to short-wave broadcasts, the sound is big and small. A radio with better automatic gain control (AGC) performance can alleviate this phenomenon.