The 2-meter amateur radio band is a portion of the VHF radio spectrum that comprises frequencies stretching from 144 MHz to 148 MHz in International Telecommunication Union region (ITU) Regions 2 (North and South America plus Hawaii) and 3 (Asia and Oceania) and from 144 MHz to 146 MHz in ITU Region 1 (Europe, Africa, and Russia). Frequencies between 30 and 300 MHz are referred to as Very High Frequency (VHF) region and those between 300 MHz and 3 GHz are referred to as Ultra High Frequency (UHF). The allocated bands for amateurs are many megahertz wide, allowing for high-fidelity audio transmission modes (FM) and very fast data transmission modes that are unfeasible for the kilohertz-wide allocations in the HF bands.
Because it is local and reliable, and because the licensing requirements to transmit on the 2-meter band are easy to meet in many parts of the world, this band is one of the most popular non-HF ham bands. The 2-meter band is often the band on which Ham radio operators make their first contacts. Obtaining a Ham operator's license consists of taking a simple test containing 35 questions covering such topics as operating procedures, rules and regulations and some minor electronics theory. There is no requirement to pass a Morse code test to be licensed to operate on the 2-meter amateur radio band.
Frequency Range and Allocation
In particular, the 2m band extends from 144 MHz to 148 MHz. The FCC Rules say that any mode (FM, AM, SSB, CW, etc.) can be used on the band from 144.100 to 148.000 MHz. The FCC has restricted 144.0 to 144.100 MHz to CW operation only. This restriction on the lower portion of the band allows for specialized weak signal operations and Earth-Moon-Earth (EME) communications that require the precision of CW modes.
When you're getting started as a Technician licensee, you have full access to all amateur frequencies above 50 MHz. Perhaps the most common band Tech's use is the 2 Meter band (144 MHz – 148 MHz). This makes the 2-meter band particularly attractive to new amateur radio operators who hold Technician class licenses, as it provides full privileges across the entire band without the frequency restrictions found in the HF bands.
VHF Band Characteristics and Properties
While "line of sight" propagation is a primary factor for range calculation, much of the interest in the bands above HF comes from use of other propagation modes. A signal transmitted on VHF from a hand-held portable will typically travel about 5–10 km (3–6 miles) depending on terrain. With a low power home station and a simple antenna, range would be around 50 km (30 miles). However, with proper equipment and techniques, much greater distances are possible.
With a large antenna system like a long yagi, and higher power (typically 100 watts or more) contacts of around 1 000 km (600 miles) using the Morse code (CW) and single-sideband (SSB) modes are common. The longest terrestrial contact ever reported on 2 metres (146 MHz) was between a station in Italy and a station in South Africa, a distance of 7 784 km (4 837 miles), using trans-equatorial anomalous enhancement (TE) of the ionosphere over the geomagnetic equator. This enhancement is known as TE, or trans-equatorial propagation and (usually) occurs at latitudes 2 500–3 000 km (1500–1900 miles) within either side of the equator.
2 Meter Band Frequency Allocations and Usage
The 2-meter band is divided into several sub-bands to organize different types of amateur radio activities and minimize interference between incompatible modes. Thus, it makes sense to have a band plan that divides the band up into segments for each type of operation. Understanding these allocations is crucial for proper band operation and avoiding interference with other users.
CW and Weak Signal Communications (144.0-144.1 MHz)
144.00-144.05 EME (CW) 144.05-144.10 General CW and weak signals The bottom 100 kHz of the 2-meter band is reserved exclusively for CW operations. At the very bottom of the 2 meter band, 144.000 to 144.100 is the CW portion, which includes Earth-Moon-Earth (EME) operation. EME operators communicate by bouncing their signals off the moon. This segment requires the most sensitive receiving equipment and highest antenna gains due to the extreme path losses involved in moonbounce communications.
SSB and Digital Modes (144.1-144.3 MHz)
144.10-144.20 EME and weak-signal SSB 144.200 National SSB calling frequency 144.200-144.275 General SSB operation 144.275-144.300 Propagation beacons The SSB calling frequency at 144.200 MHz serves as the primary meeting point for voice contacts using single sideband mode. This frequency is essential for weak signal work and long-distance VHF communications, including tropo, meteor scatter, and EME contacts.
Satellite and Experimental Modes (144.3-145.1 MHz)
144.30-144.50 New OSCAR subband 144.50-144.60 Linear translator inputs 144.60-144.90 FM repeater inputs 144.90-145.10 Weak signal and FM simplex This segment accommodates amateur satellite operations and experimental digital modes. The 2 meter band is also used in conjunction with the 70-centimeter band, or the 10-meter band and various microwave bands via orbiting amateur radio satellites. This is known as cross-band repeating.
Repeater Operations (145.1-146.0 MHz)
145.10-145.20 Linear translator outputs 145.20-145.50 FM repeater outputs 145.50-145.80 Miscellaneous and experimental modes 145.80-146.00 OSCAR subband The repeater segments are coordinated to prevent interference between adjacent repeater systems. When using a repeater, you just need to dial in the published repeater frequency and set the transmit offset, usually either + 600 kHz or – 600 kHz for a 2-meter band repeater. In some parts of North America, non-standard repeater offsets may be used, which will be indicated in the repeater directory.
Simplex Frequencies and Common Channels
Across all of North America, the National Simplex Frequency (also referred to as the calling frequency) is 146.52 MHz. 146.40-146.58 Simplex 146.400, 146.415, 146.430, 146.445, 146.460, 146.475, 146.490, 146.505 These simplex frequencies allow direct radio-to-radio communication without the use of repeaters.
In areas that use 15-kHz channels, the adjacent channels are 146.535, 146.550, 146.565 MHz, etc. moving upward. Below the calling frequency are 146.505, 146.490, 146.475 MHz and on. Choosing an appropriate simplex frequency can be a little tricky, since it depends on whether your region uses the 15-kHz or 20-kHz channel spacing. In areas that use 15-kHz channels, the adjacent channels are 146.535, 146.550, 146.565 MHz, etc. Below the calling frequency are 146.505, 146.490, 146.475 MHz and on. In areas that use 20 kHz channels, the frequencies are 146.540, 146.560, 146.580 MHz moving up and 146.500, 146.480, 146.460 MHz moving down.
Propagation Characteristics of 2 Meters
Understanding VHF propagation is essential for maximizing the potential of the 2-meter band. While line-of-sight propagation dominates most VHF communications, several propagation modes can extend communication distances far beyond normal ranges.
Line-of-Sight Propagation Basics
On VHF frequencies such as 2-meters, antenna height greatly influences how far one can talk. Typical reliable repeater range is about 25 miles (40 km). Some repeaters in unusually high locations, such as skyscrapers or mountain tops, can be usable as far out as 75 miles (121 km). Reliable range is very dependent on the height of the repeater antenna and also on the height and surroundings of the handheld or mobile unit attempting to access to the repeater.
Tropospheric Propagation and Ducting
Occasionally, signal bending in the atmosphere's troposphere known as tropospheric ducting can allow 2-meter signals to carry hundreds or even thousands of miles as evidenced by the occasional 2-meter contact between the west coast of the United States and the Hawaiian Islands, the northeast region to the Florida coast and across the Gulf of Mexico. These "Openings" as they are known, are generally first spotted by amateurs operating SSB and CW modes since amateurs using these modes are always alert for ducting or signal enhancement events.
Meteor Scatter Communications
Meteor scatter is an exciting propagation mode that allows amateur radio operators to make long-distance contacts using VHF and UHF frequencies. With the right equipment and software, it is possible to make contacts hundreds or even thousands of miles away. Meteor scatter works by bouncing radio signals off the ionized trails left by meteors. These trails are created when the meteor enters the Earth's atmosphere, and they typically last for less than a second. The ionized trails are created by the meteor's heat, which vaporizes the surrounding atmosphere, leaving behind a trail of ionized particles.
Among the options given (VHF, UHF, HF, and 2 meters), the most appropriate band is the VHF band, specifically the 2-meter band. This band is commonly used for amateur radio communications to exploit the ionized trails of meteors for brief periods of intense signal propagation. Working meteor scatter (MS) on 144 MHz (2 meters) is a fascinating part of VHF amateur radio that uses ionized trails left by meteors in the upper atmosphere to reflect radio signals over distances typically between 500 to 2,300 km.
EME (Earth-Moon-Earth) Operations
Communicating over great distances via VHF continues to fascinate many amateurs. EME (Earth-Moon-Earth) communication, also known as "moonbounce" and meteor scatter are two well known propagation techniques. The concept is simple: use the moon or the ionized trail of a meteor as a passive reflector to go way beyond line of sight. With a total path length of about 500,000 miles, EME is the ultimate DX!
To communicate over the longest distances, hams use moon bounce. VHF signals normally escape the Earth's atmosphere, so using the moon as a target is quite practical. Due to the distance involved and the very high path loss getting a readable signal bounced off the moon involves high power ~1,000 watts and steerable high gain antennas.
Sporadic E Skip and VHF Contests
Another VHF propagation event called, Sporadic E propagation; is a phenomenon involving radio reflections that can provide unexpected long-distance communications on 2 meters. Meteor scatter, sporadic E, and tropospheric ducting are the most common forms of VHF signal enhancement and are described further below. These propagation modes are particularly important during VHF contests when operators actively seek enhanced propagation conditions.
Popular Uses and Applications
The 2-meter band supports a wide variety of amateur radio activities, making it one of the most versatile bands available to amateur operators. Its popularity stems from both its accessibility to new operators and its diverse applications.
Local Repeater Communications
Much of 2-meter FM operation uses a radio repeater, a radio receiver and transmitter that instantly retransmits a received signal on a separate frequency. Repeaters are normally located in high locations such as a tall building or a hill top overlooking expanses of territory. Much of 2-meter FM operations use radio repeaters, which consist of a radio receiver and transmitter that instantly retransmits a received signal on a separate frequency. Repeaters are normally located in high locations such as a tall building or a hilltop overlooking expanses of territory.
Repeater communications form the backbone of local amateur radio activity, providing reliable communication coverage across metropolitan areas and rural regions. Local repeaters often host nets for emergency preparedness, technical discussions, and social interaction among amateur radio operators.
Emergency and Public Service
This popularity, the compact size of needed radios and antennas, and this band's ability to provide easy reliable local communications also means that it is also the most used band for local emergency communications efforts, such as providing communications between Red Cross shelters and local authorities.
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