HF Amateur Radio Bands Explained: 160m to 10m

Introduction

The HF amateur radio spectrum (160 m to 10 m) offers a wide range of propagation behaviours driven primarily by ionospheric physics, solar activity, time of day, and season. Understanding these characteristics allows operators to select the most appropriate band for reliable local, regional, or long-distance (DX) communication.

This article provides an overview of each HF band, focusing on propagation mechanisms, optimal operating times, and practical advantages and limitations.

HF Propagation Overview

HF propagation is dominated by ionospheric refraction, primarily within the:

• D layer (60–90 km) – absorbs lower frequencies during daylight
• E layer (90–120 km) – short-skip and sporadic-E
• F layer (150–400 km) – long-distance skywave (F1/F2)

Key influencing factors:

• Solar flux (SFI)
• Sunspot number
• Geomagnetic activity (Kp index)
• Time of day and season
• Transmit frequency and radiation angle

160 Metres (1.8–2.0 MHz) – Top Band

Propagation:

• Ground wave (short range)
• Night-time F-layer skywave
• Strong D-layer absorption during daylight

Best Time:

• Night only (post-sunset to pre-sunrise)
• Winter months preferred

Typical Range:

• 50–500 km ground wave
• 1,000–3,000 km at night

Pros:

• Excellent for regional night-time coverage
• Low noise floor in rural locations
• Reliable NVIS propagation

Cons:

• Large antennas required
• High atmospheric noise
• Severely limited daytime usability

Typical Uses:

DX at night, regional nets, experimental antennas

80 Metres (3.5–3.8 MHz)

Propagation:

• NVIS and short-skip at night
• D-layer absorption during daytime

Best Time:

• Evening through early morning
• Winter nights are optimal

Typical Range:

• 100–500 km (NVIS)
• Up to 2,000 km at night

Pros:

• Excellent for national and regional nets
• Predictable night-time propagation
• Moderate antenna size

Cons:

• High noise levels
• Crowded band
• Poor long-haul DX potential

Typical Uses:
Ragchews, emergency comms, contests, nets

40 Metres (7.0–7.2 MHz)

Propagation:

• Works day and night
• F-layer long-path and short-path

Best Time:

• Daytime for medium range
• Night for DX

Typical Range:

• 300–800 km daytime
• Worldwide DX at night

Pros:

• One of the most reliable HF bands
• Good balance between range and noise
• Works with modest antennas

Cons:

• Busy band
• Limited bandwidth in Region 1

Typical Uses:

DX, contests, portable operation, emergency use

30 Metres (10.1–10.15 MHz)

Propagation:

• F-layer dominated
• Very stable

Best Time:

• Day and night
• Excellent during solar minima

Typical Range:

• 1,000–5,000 km

Pros:

• Low noise
• Consistent long-distance propagation
• Excellent for digital modes

Cons:

• No phone operation (CW/data only)
• Narrow band allocation

Typical Uses:
CW, FT8, WSPR, propagation study

20 Metres (14.0–14.35 MHz)

Propagation:

• F2-layer global propagation
• Minimal D-layer absorption

Best Time:

• Daytime and early evening
• Year-round usability

Typical Range:

• 1,000–10,000+ km

Pros:

• Premier DX band
• Predictable openings
• Efficient antennas

Cons:

• Can be crowded
• Less effective for short-range comms

Typical Uses:
DX, contests, expeditions, SSB and digital

17 Metres (18.068–18.168 MHz)

Propagation:

• Similar to 20 m but more solar-dependent

Best Time:

• Daytime
• Peaks during higher solar activity

Typical Range:

• Worldwide during openings

Pros:

• Less crowded than 20 m
• Good signal-to-noise ratio

Cons:

• Narrow allocation
• More sensitive to solar conditions

Typical Uses:
DX, casual operating, digital modes

15 Metres (21.0–21.45 MHz)

Propagation:

• Strongly dependent on solar cycle
• F2-layer during high SFI

Best Time:

• Late morning to afternoon
• Solar maximum years

Typical Range:

• Global during good conditions

Pros:

• Excellent DX when open
• Low noise
• Small antennas

Cons:

• Can be completely closed during solar minima

Typical Uses:
DX, contests, beam antenna operation

12 Metres (24.89–24.99 MHz)

Propagation:

• Similar to 10 m but slightly more reliable

Best Time:

• Daytime
• High solar flux

Typical Range:

• Intercontinental during openings

Pros:

• Quiet band
• Excellent DX potential

Cons:

• Rarely open at solar minimum
• Narrow allocation

Typical Uses:
DX, experimentation, low-power operation

10 Metres (28.0–29.7 MHz)

Propagation:

• F2-layer (solar max)
• Sporadic-E (summer)
• Ground wave and line-of-sight

Best Time:

• Daytime
• Summer for Sporadic-E

Typical Range:

• Local to worldwide depending on mode

Pros:

• Very low noise
• Small antennas
• High signal strengths

Cons:

• Highly unpredictable
• Solar-cycle dependent

Typical Uses:
DX, FM repeaters, beacons, experimentation

Summary Table

Closing Remarks

Each HF band serves a distinct operational niche. Successful HF operation is less about raw power and more about choosing the right band at the right time, informed by ionospheric conditions and station capability.

Understanding these characteristics allows amateurs to maximise reliability, efficiency, and enjoyment—whether operating from a home station, portable setup, or during emergency conditions.

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