What Are High Frequency (HF) Bands?
High Frequency (HF) bands are a range of radio frequencies from 3 to 30 MHz that allow long-distance communication, including intercontinental contacts. They are a core part of amateur radio activity, offering broad opportunities for technical experimentation, skill improvement, and participation in international competitions.
The HF spectrum is preferred by amateur radio operators because it enables communication over thousands of kilometers using ionospheric propagation. Operating in this range requires knowledge of radio wave propagation, proficiency in different modes (CW, SSB, digital), and the ability to adapt to varying atmospheric conditions.
History and Importance
HF communications have a long-standing history in amateur radio. As early as the beginning of the 20th century, radio amateurs around the world experimented with HF bands, discovering that, thanks to ionospheric reflections, it was possible to establish contacts over great distances.
In Bulgaria, HF contacts have been an active part of amateur radio activities since the mid-20th century. Over the years, Bulgarian operators have participated in and won prestigious international contests, with HF remaining an important element in training, as well as in emergency communication situations.
Disciplines and Activities
Various amateur radio activities take place on HF bands:
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DXing – Making contacts with the most distant stations possible around the globe.
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Contests – Competitions in which operators strive to make the maximum number of contacts within a set time.
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Technical experiments – Testing new antennas, operating modes, and techniques to optimize long-distance communication.
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Training ground – HF is an excellent way for new amateurs to learn the fundamentals of radio communication and develop operational skills.
Main HF Bands and Their Characteristics
160 meters (1.8 – 2.0 MHz)
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Also called the “Top Band.”
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Excellent for night-time contacts over medium distances.
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Requires large antennas and low-noise conditions.
80 meters (3.5 – 3.8 MHz)
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Very good for evening and night contacts.
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Suitable for regional QSOs and nighttime DX with low noise levels.
40 meters (7.0 – 7.2 MHz)
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One of the most versatile bands.
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Works well both day and night, providing both short- and long-distance contacts.
30 meters (10.1 – 10.15 MHz)
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Primarily used for CW and digital modes.
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Excellent stability and low noise, ideal for DX contacts with low power.
20 meters (14.0 – 14.35 MHz)
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The most popular DX band.
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Suitable for intercontinental contacts at any time of day during good solar conditions.
17 meters (18.068 – 18.168 MHz)
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A quieter QSO band with less congestion during contests.
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Good for long-distance contacts during medium to high solar activity.
15 meters (21.0 – 21.45 MHz)
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Excellent for daytime intercontinental contacts when the ionosphere is active.
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Limited performance during low solar activity.
12 meters (24.890 – 24.990 MHz)
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Less frequently used but offers excellent DX opportunities during solar cycle peaks.
10 meters (28.0 – 29.7 MHz)
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The highest HF band.
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During high solar activity, it enables worldwide contacts with low power and simple antennas.
Rules and Ethics
Operating on HF bands is carried out according to international amateur radio regulations and national requirements. Each operator should:
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Clearly identify (callsign) at the beginning and end of each contact;
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Follow the band plans for different modes;
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Keep an accurate log of contacts;
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Adhere to amateur radio ethics and avoid unnecessary interference.
Age Groups and Participation
HF contests are open to all licensed amateur radio operators without age restrictions. Some international championships also have separate youth categories to encourage the next generation of operators.
