↑ HF bands allocated for radio amateurs and their characteristics

By Doron Tal, 4X4XM

The High Frequency (HF) bands for radio amateurs provide a range of frequencies that, when chosen correctly, can ensure reliable communication.

  1. The 160-meter band, spanning 1.8-2.0 MHz, can provide day-time ground wave communication up to 150 km. Nighttime communication via F2-layer skip is possible in particular at winter evenings. A magnetic loop receiving antenna would be required to boost signal to noise at all times.
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  2. Moving up, the 80-meter band (3.5–3.8 MHz Region 1; 3.5–3.9 MHz Region 3; 3.5–4.0 MHz Region 2) is is the lowest HF band. Like 160m it suffers a daytime D-layer absorption. During winter nights signals can propagate halfway around the world via F-layer.
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  3. The 60-meter band (5.3305-5.405 MHz) is unique, allowing regional communication with limited power.
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  4. At The 40-meter band (7.0-7.2 MHz Regions 1&3, up to 7.3 Region 2) is a popular amateur band due to its clear skip zone during the day, less severe D-layer absorption, and reliable worldwide communication via F2 during night. Even during low solar activity this band may be open for worldwide DX throughout the night.
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  5. The 30-meter band (10.100-10.150 MHz) is a unique communication band that shares characteristics of daytime and nighttime bands, allowing communication up to 3000 km during the day and at least half-way around the world at nights. It is open 24/7 via F2, with minimal variation over the 11-year solar cycle.
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  6. The 20-meter band (14.000-14.350 MHz) is a popular choice for international communication, renowned for its daylight reliability. It can stay open during solar maximum periods, with skip distance and E-Layer propagation detected along short paths.
    7.   The 17, 15, 12, and 10-meter bands offer higher frequencies for longer-range communication, but are more dependent on solar activity-influenced ionospheric conditions.
  7. The 17 m band, (18.068-18.168 MHz) similar to the 20-m band, is affected by fluctuating solar activity. High solar activity ensures reliable daytime and early-evening long-range communication, while moderate years may only open during sunlight hours. At solar minimum, 17 m will open to middle and equatorial latitudes, but only for short periods during mid day on north - south paths.
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  8. The 15 m band (21.000-21.450 MHz) is a prime DX Band during peak years, but is sensitive to changing activity, closing after sunset. During solar minimum the band is closed except for infrequent north-south transequatorial circuits. Sporadic E is occasionally observed in early summer and mid-winter, but not as common.
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  9. The 12 m band (24.890-24.990 MHz) combines 10 and 15 m bands charactaristics, may stay open after sunset during solar maximums. Moderate solar activity opens to low and middle latitudes during daytime hours, with occasional daytime openings in low latitudes, over north-south paths. The main sporadic-E season from late spring through summer and short openings may be observed in mid-winter.
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  10. The 10 m band (28.000-29.700 MHz) is known for its extreme variations in propagation modes and characteristics. During solar maxima, it is efficient for long-distance F2 propagation, with DX abundant with modest equipment. During moderate solar activity, it opens only to low and transequatorial latitudes around noon. This band shares propagation modes with VHF, such as meteor scatter, aurora, auroral E, and Transequatorial spread-F. Techniques similar to VHF can be effective on 10 meters.
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The mentioned bands enable amateur radio operators to engage in diverse and global communication across various atmospheric conditions.

The Understanding HF Propagation Project provides radio amateurs with a detailed overview and tutorials on several aspects of HF propagation.

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