VHF and UHF Amateur Radio Bands Explained: 2m, 70cm, and 23cm

Introduction

Unlike HF, VHF and UHF amateur radio bands are not primarily dependent on ionospheric refraction. Instead, they are dominated by line-of-sight propagation, terrain, antenna height, and a range of tropospheric and ionospheric enhancement mechanisms.

The 2 m, 70 cm, and 23 cm bands form the backbone of local, regional, and experimental amateur radio, supporting FM, SSB, digital voice, weak-signal modes, satellites, and high-speed data links.

VHF/UHF Propagation Overview

Primary propagation mechanisms include:

• Line-of-sight (LOS) – dominant mode
• Tropospheric refraction and ducting – enhanced range
• Tropospheric scatter – weak-signal beyond LOS
• Sporadic-E – mainly affects 2 m
• Aircraft scatter – short-duration reflections
• Earth–Moon–Earth (EME) – weak-signal paths at 2 m and above

Key influencing factors:

• Antenna height and horizon clearance
• Terrain and urban clutter
• Weather systems and temperature inversions
• Transmit frequency and polarization

2 Metres (144–146 MHz)

Propagation:

• Primarily line-of-sight
• Enhanced by tropospheric lift and Sporadic-E
• Occasional EME and meteor scatter

Best Time:

• All day for local work
• Early morning and evening for tropo
• Summer for Sporadic-E

Typical Range:

• 20–50 km handheld to handheld
• 50–150 km mobile/base
• 500–2,000 km during Sporadic-E

Pros:

• Most popular VHF band
• Excellent repeater coverage
• Supports FM, SSB, digital, satellite
• Modest antenna requirements

Cons:

• Congestion in urban areas
• Limited range without elevation or enhancements
• Noise from man-made sources in cities

Typical Uses:
Repeaters, simplex FM, SSB weak-signal, satellites, emergency communications

70 Centimetres (430–440 MHz)

Propagation:

• Line-of-sight dominant
• Strong urban reflection and diffraction
• Tropospheric enhancement

Best Time:

• All day
• Tropo more likely during high-pressure systems

Typical Range:

• 10–30 km handheld
• 30–80 km base to base
• 300–1,000 km during strong tropo

Pros:

• Smaller antennas
• Better building penetration than 2 m
• Less crowded in rural areas
• Ideal for digital voice and data

Cons:

• Shorter natural range than 2 m
• More sensitive to feedline losses
• Shared spectrum with other services

Typical Uses:

DMR/D-STAR/C4FM, FM repeaters, data links, ATV, satellites

23 Centimetres (1240–1300 MHz)

Propagation:

• Strictly line-of-sight
• Highly directional
• Susceptible to atmospheric absorption and losses

Best Time:

• All day
• Stable weather improves performance

Typical Range:

• 5–20 km omnidirectional
• 50–200 km with directional antennas

• 700 km with EME

Pros:

• Wide bandwidth availability
• Very small antennas
• Low noise floor
• Ideal for experimentation

Cons:

• High feedline and connector losses
• Expensive RF components
• Poor penetration of foliage and buildings

Typical Uses:
Microwave SSB, DATV, high-speed data, EME, satellite uplinks

Band Comparison Summary

Antenna and Station Engineering Considerations

• Height is critical: increasing antenna height often yields greater benefit than increasing power.
• Feedline losses increase rapidly with frequency—use low-loss coax or waveguide at 70 cm and above.
• Polarization matters: FM typically vertical, SSB/DX horizontal.
• Directional antennas (Yagi, dish) dramatically improve performance on UHF and microwave bands.

Closing Remarks

VHF and UHF operation rewards good engineering practice: careful antenna placement, low-loss feedlines, and an understanding of propagation enhancements. While often perceived as “local” bands, 2 m, 70 cm, and 23 cm can deliver remarkable long-distance results when conditions align.

These bands remain central to experimentation, emergency communications, and modern digital amateur radio.

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