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ENCYCLOPEDIA OF RADIO ELECTRONICS AND ELECTRICAL ENGINEERING amateur bands. Encyclopedia of radio electronics and electrical engineering
Encyclopedia of radio electronics and electrical engineering / Beginner radio amateur Radio waves do not belong to any country in the world, and it would seem that everyone in the world is free to use any radio frequencies for their own purposes. But imagine what chaos would be created in the ether! Due to mutual interference, reliable radio communications, broadcasting and everything else related to the use of radio waves (radar, radio navigation, etc.) would simply be impossible. It is for this reason that even at the dawn of radio, the international community came to the understanding that there should be an international organization that would regulate the use of radio frequencies in the world by various services, establish rules for their use, as well as technical standards for radio electronic equipment. Such an organization was the International Telecommunication Union (ITU), whose members are currently the vast majority of countries in the world. Of the ITU documents, it is necessary to highlight the "Radio Regulations", since it is in it that it is written for the entire radio spectrum (from kilohertz to hundreds of gigahertz!), At what frequencies certain civil radio services from different countries of the world can operate. In international practice, groups of users, united by goals and objectives, are called "services". One of them is amateur radio. Here is how the "Radio Regulations" define it: "Amateur radio service is a radio communication service for the purposes of self-improvement, mutual communication and technical research carried out by radio amateurs, that is, persons who have the proper permission for this and are engaged in radio engineering solely from personal interest and without extracting material benefits". It is in the "Radio Regulations" that it is written which frequency bands can be allowed for amateur radio communication by their citizens of the Communications Administration of various countries of the world. On short waves, the "Radio Regulations" have allocated nine frequency bands, otherwise called amateur bands. There are also frequency bands allocated for amateur radio communications on ultrashort waves, as well as on long waves. But at the first stage, we will only talk about HF. For brevity, amateur bands are usually referred to by the approximate wavelength or by the lower frequency of the corresponding band (rounded to two significant figures). Here are these ranges (the names are "in meters", "in megahertz" and the frequency band of this range):
Radio amateurs are allowed to use various types of communication. Historically, the first were, of course, radio communications by telegraph and telephone. Over time, direct-printing radio communications (teletype) and the possibility of transmitting images via amateur channels (slow-scan television) were added to them. Recently, digital forms of radio communication have been intensively developed, in which the processing of transmitted and received information is carried out at an amateur radio station using computers. A feature of amateur radio communications is that amateur radio stations are not allocated specific frequencies (as, for example, broadcasting or communication professional radio stations), but the above frequency bands. In other words, a radio amateur is free to choose an operating frequency within the amateur bands allowed for use by the country's Communications Administration. The latter depends on the qualifications of the radio amateur and on his work experience and is taken into account when issuing him a permit to operate an amateur radio station. So, in our country, novice radio amateurs are allowed to have a radio station of the fourth category and work by telegraph and telephone only on the amateur band of 160 meters. In order to make it easier for radio amateurs to navigate within the amateur bands with such a “freedom”, there is an additional division by type of work: there are areas for communication only by telegraph, for communication by telephone, as well as frequencies near which enthusiasts of specialized types of radio communication (digital modes, television with slow sweep, etc.). It should be noted that the frequencies allocated for radio amateurs by the "Radio Regulations" differ somewhat in the three regions of our planet. The fact is that the whole world was once conditionally divided by the International Telecommunication Union into three regions. In "our" - the 1st region, for example, includes all the countries of Europe, Africa, Asia Minor, Mongolia and all the countries formed from the USSR. The 2nd region includes the countries of North, Central and South America, and the 3rd region - the rest of Asia and the countries of the Pacific basin. The differences in question are actually not that big and only apply to the low frequency bands (160, 80 and 40 meters). The amateur bands are more or less evenly "embedded" in almost the entire frequency band, which is commonly called short waves. Moreover, the range of 160 meters (or 1,8 MHz), strictly speaking, is referred to as "intermediate waves", but for brevity and simplicity, shortwave does not distinguish it and speak of nine KB bands. The nature of the propagation of radio waves, or, as they say, their passage for all these ranges, differs significantly. This makes it possible to almost always choose the optimal range for establishing links with the desired correspondent. The table shows the distribution of amateur bands by type of work, adopted in the 1st region of the International Telecommunication Union.
In this table, for the first time, we meet with some of the abbreviations (radio codes) adopted in amateur radio. These are the designations of the types of radiation used in amateur radio communications: CW - telegraph (communication using "morse code"); PHONE - telephone (voice communication); DIGIMODE - digital modes of communication (including here the traditional teletype); SSTV - slow scan television (transmission of slowly changing pictures); FAX - facsimile communication (transmission of still images). The abbreviation IBP stands for International Beacon Project. As is known, the passage of radio waves to a large extent depends on the activity of the Sun and is subject to seasonal and daily changes. This is especially pronounced on high-frequency amateur bands, so radio amateurs install radio beacons that operate within amateur bands and allow you to check the presence of passage in one direction or another and evaluate the possibility of conducting radio communications with shortwaves of the respective countries. For such beacons in the amateur bands, frequencies are reserved, and their allocation and use are coordinated by the International Amateur Radio Union under the IBP program. Author: B.Stepanov (RU3AX), Moscow
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