2 meters

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The 2 meter amateur radio band is a portion of the VHF radio spectrum, comprising frequencies stretching from 144.000 MHz to 148.000 MHz in ITU Regions 2 (North & South America plus Hawaii) and 3 (Asia and Oceania)[1] and from 144.000 to 146.000 MHz in ITU Region 1 (Europe, Africa, and Russia).[2][3] The license privileges of amateur radio operators include the use of frequencies within this band for telecommunication, usually conducted locally within a range of about 100 miles (161 km).

Contents

[edit] Operating on 2 meters

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[4], this band is one of the most popular non-HF ham bands. This popularity 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[5].

Much of 2-meter FM operation uses a radio repeater, a radio receiver and transmitter that instantly retransmits a signal over a longer distance. Simple radios for FM repeater operation have become plentiful and inexpensive in recent years. A fully-functional FM transceiver and antenna can be obtained for under $200 US.

[edit] DX

While 2 meters is best known as a local band, there are many opportunities for long distance (DX) communications. Occasionally, bending in the atmosphere's troposphere (ducting) can allow 2-meter signals to carry hundreds of miles. This is called a lift.

In rare cases, Sporadic E propagation can bring contacts well over a 1,000 miles (1,609 km). 2 Meters is also utilized in conjunction with 70 cm (Mode B or V/U) on some amateur radio satellites, giving distances of up to around 3,000 miles (4,828 km) with a Low Earth Orbit satellite.

A set of 2 long Yagi antennas for the 2 meter band fed in phase to obtain more gain and narrow main lobe of radiation (WA6PY)
A set of 2 long Yagi antennas for the 2 meter band fed in phase to obtain more gain and narrow main lobe of radiation (WA6PY)

By speeding up Morse code using an audio tape recorder, or using a computer, very short bursts of signal can be bounced off the ionised gas trail of meteor showers allowing dx. This is often called Burst transmission.

Another phenomenon that produces upper atmosphere ionisation suitable for 2M DXing are the auroras. Since the ionisation persists much longer than meteor trails, regular audio signals can be used, but the constant movement of the ionised gas leads to heavy distortion of the signals causing the audio to sound 'ghostly' and whispered.

To communicate over the longest distances HAMs use moonbounce. Literally bouncing the VHF signals off the moon. VHF signals normally easily escapes the earth's atmosphere. Due to the delay of the signal travelling to the moon and back, a person transmitting may hear the end of his own transmission returning.

[edit] Band plan

Below is a common band plan for 2 meters. Note that in some areas (generally whole states) the channel spacing is 20 kHz. Some areas use 15kHz spacing.

Please note, this is the band plan for the USA.

In the UK, the band extends from 144 MHz to 146 MHz.

To summarize:

  • 144.000 to 144.400 narrowband modes.
  • 144.500 to 145.000 is an "all mode" section.
  • 145.000 to 145.200 are VHF repeater inputs.
  • 145.200 to 145.600 are Simplex channels (12.5kHz spacing).
  • 145.600 to 145.800 are the repeater outputs.

Space communications are above 145.800 to the band edge.

[edit] Sample band plan

144.000–144.100 MHz CW only, as restricted by FCC Part 97
144.100–144.275 MHz CW and SSB
144.275–144.300 MHz CW propagation beacons
144.300–144.500 MHz Satellite
144.510–144.890 MHz FM repeater inputs (600 kHz splits)
  • FM repeater inputs are spaced 20 kHz apart (144.510, 144.530, 144.550, etc.)
  • FM repeater inputs are coupled with outputs from 145.110 to 145.490
144.910–145.090 MHz Packet and FM simplex
  • Packet channels are spaced 20 kHz apart on the odd frequencies (144.910, 144.930, 144.950, etc.)
  • FM simplex channels are spaced 20 kHz apart on the even frequencies (144.920, 144.940, 144.960, etc.)
145.110–145.490 MHz FM repeater outputs (600 kHz splits)
  • FM repeater outputs are spaced 20 kHz apart (145.110, 145.130, 145.150, etc.)
  • FM repeater outputs are coupled with inputs from 144.510 to 144.890
145.510–145.790 MHz FM simplex, digital and satellite
  • Channels are spaced 20 kHz apart (145.510, 145.530, 145.550, etc.)
145.800–146.000 MHz Satellite
146.010–146.385 MHz FM repeater inputs (600 kHz splits)
  • FM repeater inputs are spaced 15 kHz apart (146.010, 146.025, 146.040, etc.)
  • FM repeater inputs are coupled with outputs from 146.610 to 146.985
146.400–146.595 MHz FM simplex
  • FM simplex channels are spaced 15 kHz apart (146.400, 146.415, 146.430, etc.)
146.610–146.985 MHz FM repeater outputs (600 kHz splits)
  • FM repeater outputs are spaced 15 kHz apart (146.610, 146.625, 146.640, etc.)
  • FM repeater outputs are coupled with inputs from 146.010 to 146.385
147.000–147.390 MHz FM repeater outputs (600 kHz splits)
  • FM repeater outputs are spaced 15 kHz apart (147.000, 147.015, 147.030, etc.)
  • FM repeater outputs are coupled with inputs from 147.600 to 147.990
  • In some areas, 147.000 MHz is coupled with 146.400 MHz as an input instead of 147.600 MHz.
147.405–147.585 MHz FM simplex
  • FM simplex channels are spaced 15 kHz apart (147.405, 147.420, 147.435, etc.)
147.600–147.990 MHz FM repeater inputs (600 kHz splits)
  • FM repeater inputs are spaced 15 kHz apart (147.600, 147.615, 147.630, etc.)
  • FM repeater inputs are coupled with outputs from 147.000 to 147.390

[edit] Links to 2m propagation sites

[edit] References

  1. ^ US Amateur Radio Frequency Allocations. http://www.arrl.org/FandES/field/regulations/allocate.html accessed 12 May 2008.
  2. ^ RSGB UK band plan. http://www.rsgb.org/spectrumforum/bandplans/RSGB%20Band%20Plan%20master.pdf or http://www.rsgb-spectrumforum.org.uk/Papers/RSGB%20Band%20Plan%20master.htm Accessed 14 May 2008.
  3. ^ Sharing spectrum with other services a ham radio reality. The ARRL Letter, Vol. 20, No. 2. http://www.arrl.org/arrlletter/01/1102/ Accessed 14 May 2008.
  4. ^ http://www.rsgb.org/getlicence/#foundation RSGB licensing guide
  5. ^ http://www.rsgb.org/emergency/ RSGB Radio Emergency & Public Service Communications website
Very high frequency (VHF) and ultra high frequency (UHF) amateur radio bands
VHF UHF
6 m 4 m 2 m 1.25 m 70 cm 33 cm 23 cm 13 cm
50 MHz 70 MHz 144 MHz 219–220 MHz 420 MHz 902 MHz 1.24 GHz 2.3–2.31 GHz
54 MHz 70.5 MHz 148 MHz 222–225 MHz 450 MHz 928 MHz 1.3 GHz 2.39–2.45 GHz


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