1.25 meters
From Wikipedia, the free encyclopedia
1.25 Meters is an amateur radio band unique to ITU Region 2. It ranges from 222 to 225 MHz in the United States and from 220 to 225 MHz in the rest of Region 2. The 1.25 meter band is part of the VHF spectrum, and is primarily used for more local communications as opposed to bands lower in frequency.
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[edit] History
The 1.25 meter band has a very long and colorful history dating back to before World War II.
[edit] The beginning
The history of the 1.25 meter band can be traced back to the Cairo Conference in 1938. It was there that FCC gave U.S. amateurs two "new" VHF bands: 2.5 meters (112 MHz) and 1.25 meters (224 MHz). Both bands (as well as the 440 MHz Band) were the natural harmonics of the 5 meter band. The 2.5 meter band was later reallocated to 144 - 148 MHz when the original allocation was used for aircraft communication during World War II, becoming the modern-day 2 meter band, while the 1.25 meter band grew to be 5 MHz wide, spanning 220 - 225 MHz.
[edit] The VHF/UHF Explosion
Amateur use of VHF and UHF allocations exploded in the late 1960s and early 1970s as repeaters started going on the air. Repeater use sparked a huge interest in the 2 meter and 70 centimeter (420 - 450 MHz) bands, however this interest never fully found its way into the 1.25 meter band. Many amateurs attribute this to the fact that there was an abundance of commercial radio equipment designed for 136 - 174 MHz and 450 - 512 MHz that amateurs could easily modify for use on 2 meters and 70 centimeters. There were no commercial frequency allocations near the 1.25 meter band, therefore there was no commercial radio equipment available. This meant that amateurs who wanted to experiment with the 1.25 meter band had to do so by building their own receivers and transmitters for the band or by buying one of the few radios available from amateur radio equipment manufacturers.
Further, since the band is allocated only in ITU Region 2, the major equipment manufacturers (Kenwood, Yaesu and Icom), for the most part, do not often offer transceiver models which cover the frequency range. (see Novice Licensees Get Privileges). This helps to continue the lack of usage of the 1.25 meter band, though the equipment manufacturers argue that when they have produced equipment, it hasn't sold well as compared to other products. In recent years, Kenwood and Yaesu have both included the 1.25 meter band in some of their multi-band handheld transceivers. The Kenwood TH-F6A, ICOM IC-T90 and the Yaesu VX-7R include coverage of the 1.25 meter band in addition to the more popular 2 meter and 70 centimeter bands. It is widely believed that these are two of the most popular handhelds available right now. The only 1.25 meter non-handheld widely available new today is offered by Alinco, another Japanese manufacturer. The Alinco 235T, a 25-watt FM-only radio intended primarily for mobile use, is quite popular. In the few regional pockets of heavy 1.25 meter activity, the 235T is the radio of choice.
[edit] Novice Licensees Get Privileges
By the 1980s, amateur use of 2 meters and 70 centimeters was at an all time high while activity on 1.25 meters remained stagnant. In an attempt to increase use on the band, many amateurs called for holders of novice class licenses (the entry-level class at that time) to have voice privileges on 1.25 meters. In 1987, the FCC modified the novice license to allow holders voice privileges on portions of the 1.25 meter and 23 centimeter (1.24 - 1.30 GHz) bands. In response, some of the bigger amateur radio equipment manufacturers like Yaesu and Icom started producing equipment for 1.25 meters, however it never sold well and by the early 1990s, most manufacturers had stopped producing equipment for the band.
[edit] Reallocation
In the late 1980s, UPS began lobbying the FCC to reallocate part of the 1.25 meter band to the Land Mobile Service. UPS had well publicized plans to use the band to develop a narrow-bandwidth wireless voice and data network using a mode called ACSSB (amplitude-companded single sideband). UPS' main argument for the reallocation was that the amateur use of the band was very sparse and that the public interest would be better served by reallocating part of the band to a service that would put it to good use.
In 1988, over the objections of the amateur radio community, the FCC adopted the 220 MHz Allocation Order which reallocated 220 - 222 MHz to private and Federal Government land mobile use while leaving 222 - 225 MHz exclusively for amateur use. The reallocation proceeding took so long however, that UPS eventually pursued other means of meeting their communications needs. UPS entered into agreements with GTE, McCall, Southwestern Bell and Pac-Tel to use cellular telephone frequencies to build a wireless data network. With the 220 - 222 MHz band now left unused, the FCC issued parts of the band to other private commercial interests via a lottery in the hopes that it would spark development of super narrowband technologies. It was the FCC's hope that development of these technologies would help them gain acceptance in the marketplace.
[edit] The 1.25 Meter Band Today
Today, the 1.25 meter band is used by many amateurs who have an interest in the VHF spectrum.
There are pockets of widespread use across the United States, mainly in New England and western states such as California and Arizona with more sporadic activity elsewhere. The number of repeaters on the 1.25 meter band has grown over the years to approximately 1,500 nationwide as of 2004.
The attention that 1.25 meters received in the late 1980s and early 1990s due to the reallocation of the bottom 2 MHz sparked a renewed interest in the amateur community. Many amateurs feared that if activity on 1.25 meters remained sparse, it would only be a matter of time until the FCC reallocated the remaining 3 MHz to another service. Today, while not as widely available as 2 meter and 70 centimeter equipment, 1.25 meter equipment is much easier to obtain than it has been in the past and there is new handheld and mobile equipment being produced by amateur radio manufacturers. It is estimated that more amateurs have 1.25 meter equipment now than at any point in the past.
[edit] Propagation Characteristics
Enthusiasts of the either the 2 meter and 70 centimeter bands cite characteristics about one band that makes them prefer it to the other. Many 2 meter enthusiasts like the longer distance propagation and lower susceptibility to multipath as compared to 70 centimeters while 70 centimeter enthusiasts like the better building penetration characteristics and the lower noise floor level as compared to 2 meters.
Since the 1.25 meter band is situated right between 2 meters and 70 centimeters in the radio spectrum, many amateurs like to say that 1.25 meters offers the "best of both worlds". This means that 1.25 meters offers a taste of the more desirable characteristics of both the 2 meter and 70 centimeter bands.
On one hand, if one assumes that the transmitting antenna's wavelength, height above average terrain and effective radiated power is equal, a transmitted signal on 1.25 meters will, generally speaking, usually travel equally as far as that same signal would if transmitted on 2 meters as well as an equally low susceptibility to multipathing. On the other hand, the wavelength of 1.25 meters is closer to that of 70 centimeters, thus it tends to have building penetration and noise floor characteristics that more resemble those of 70 centimeters.
[edit] Band Plan (US)
Below is an example band plan for the 1.25 meter band.
[edit] Sample Band Plan
| 222.000 - 222.025 MHz | EME (Earth-Moon-Earth) |
| 222.050 - 222.060 MHz | CW propagation beacons |
| 222.100 - 222.150 MHz | CW and SSB |
| 222.160 - 223.380 MHz | FM repeater inputs (1.6 MHz splits)
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| 223.400 - 223.520 MHz | FM simplex communication
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| 223.520 - 223.640 MHz | Packet |
| 223.640 - 223.700 MHz | FM control links and remote bases |
| 223.760 - 224.980 MHz | FM repeater outputs (1.6 MHz splits)
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[edit] Frequencies of Note
- CW and SSB calling frequency is 222.100 MHz.
- FM simplex calling frequency is 223.500 MHz.
[edit] Band Plan (Canada)
Industry Canada has officially abolished the use of 220 - 222 MHz for amateur use effective as of January 2006, however the allocation was originally 220 - 225 MHz so 3 MHz still remain useable.
| 222.000 - 222.025 MHz | EME (Earth-Moon-Earth) |
| 222.050 - 222.060 MHz | CW propagation beacons |
| 222.100 - 222.150 MHz | CW and SSB |
| 222.160 - 223.380 MHz | FM repeater inputs (1.6 MHz splits)
|
| 223.400 - 223.520 MHz | FM simplex communication
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| 223.520 - 223.640 MHz | Packet |
| 223.640 - 223.700 MHz | FM control links and remote bases |
| 223.760 - 224.980 MHz | FM repeater outputs (1.6 MHz splits)
|
[edit] Current Amateur Radio Equipment for 1.25 Meters
Below is a list of current, in-production, amateur radio equipment that can both receive and transmit on the 1.25 meter band.
[edit] Handheld Transceivers
[edit] Mobile Transceivers
- ADI AR-247
- Alinco DR-235T
[edit] Past Amateur Radio Equipment for 1.25 Meters
Below is a list of discontinued amateur radio equipment that has been produced for the 1.25 meter band. This equipment dates as far back as the mid 1970s.
[edit] Handheld Transceivers
- Alinco DJ-280T
- Icom IC-03AT
- Icom IC-3A/AT
- Icom IC-3SAT
- Icom IC-P3AT
- Icom IC-V21AT
- Kenwood TH-315A
- Kenwood TH-31AT
- Kenwood TH-F6
- Pryme PR-222
- Standard C228A
- Standard C288A
- Tempo S2
- Yaesu FT-33R
- Yaesu FT-103R
- Yaesu FT-109R
[edit] Mobile Transceivers
- Azden PCS-4200
- Azden PCS-6200
- Azden PCS-7200
- Clegg FM-76
- Icom IC-2330A
- Icom IC-37A
- Icom IC-38A
- Icom IC-900A with 220 MHz module installed
- Icom IC-901A with 220 MHz module installed
- KDK FM-4033
- Kenwood TM-321A
- Kenwood TM-331A
- Kenwood TM-621A
- Kenwood TM-631A
- Kenwood TM-641A
- Kenwood TM-642AD
- Kenwood TM-742A
- Kenwood TR-3530
- Midland 13-509
- Midland 13-513
- Ten-Tec 1230
- Yaesu FT-127
- Yaesu FT-311RM
[edit] Base Stations
- Drake UV-3
- Icom IC-375A
- Yaesu FT736R with 220 MHz module installed
[edit] External links
Below are links to various sites dealing with the 1.25 meter band.
[edit] "Home-Brew" Projects
- Bob Simpleton's Guide to a 222 MHz "Quickie Antenna"
- An N6ZAV J-Pole Antenna for 222 MHz
- VE3CVG's 222 MHz 6 Element Plumber's Delight Yagi Antenna
- The W1VT 222 MHz Transverter
- The W1GHZ 222 MHz Transverter for the Yaesu FT-817
- The Ramsey Electronics 220-225MHz receiver kit
[edit] Antenna Manufacturers
- Comet Antenna/Maldol Antennas
- Cushcraft Corporation
- Diamond Antenna
- Hustler Antennas
- Larsen Electronics
[edit] Radio Manufacturers
[edit] Hand Held and Mobile Transceiver Reference Guides
Beyond setting up a radio to receive and transmit on particular frequencies and modes of operation, the latest generation amateur radio transceivers employ digital control ciruitry to provide a wide variety of features: various memory modes, multiple scanning techniques, repeater access control, signal filtering methods plus a variety of power saving strategies and other operator conveniences.
Simplified Operating and Programming guides for transceivers from the above listed manufacturers are available from the following sources:
| Very high frequency (VHF) and Ultra high frequency (UHF) Amateur radio bands | |||||||
| VHF | UHF | ||||||
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| 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 |
