5-centimeter band
| 5-centimeter band | |
|---|---|
| Frequency range | 5650–5925 MHz in the Americas; 5650–5850 MHz in Regions 1 and 3 |
| Wavelength | About 5 cm |
| Group | SHF (microwave) |
| US license | Technician and above, full privileges |
| Operating | |
| Weak-signal calling frequency (US) | 5760.100 MHz |
| Narrowband center (IARU Region 1) | 5760.200 MHz |
| Satellite uplink | 5650–5670 MHz |
| Satellite downlink | 5830–5850 MHz |
| Sharing | |
| Status | Secondary |
| Shared with | Radar, satellite uplinks, Wi-Fi and ISM devices |
The 5-centimeter band is the amateur microwave band from 5650 MHz up to 5850 MHz in most of the world and up to 5925 MHz in the Americas.[1] Hams call it "5.7 GHz", "5760" after its narrowband calling area, or, in the UK, the 6-centimeter band.[2] It sits between the 13- and 3-centimeter bands and shares much of its character with both: narrowband weak-signal contacts, satellite links, rain scatter and, because it overlaps the 5.8 GHz unlicensed band, high-speed data networks built from adapted Wi-Fi equipment.
Allocations
| Where | Amateur frequencies | Notes |
|---|---|---|
| United States (ITU Region 2) | 5650–5925 MHz | Secondary to government radar[1][3] |
| ITU Regions 1 and 3 | 5650–5850 MHz | National rules may allow less[1] |
| United Kingdom | 5650–5680, 5755–5765 and 5820–5850 MHz | Three separate blocks[4] |
Amateurs are secondary throughout.[5] In the US, Part 97 requires them to avoid interfering with, and to accept interference from, government radiolocation, and to accept interference from industrial, scientific and medical (ISM) equipment between 5725 and 5875 MHz.[3] They must also protect mobile services of other countries in 5650–5725 MHz.[3] The top 75 MHz of the band, 5850–5925 MHz, is available to amateurs only in ITU Region 2 (the Americas), where they are secondary to fixed, fixed-satellite and mobile services.[1][5] In the US those mobile services are limited to vehicle-to-vehicle Intelligent Transportation System links, and since 2021 the lower 45 MHz (5850–5895 MHz) has also been open to unlicensed Wi-Fi.[3][6] That FCC decision left the amateur allocation unchanged.[6] See IARU regions for how the regional plans are divided.
What you'll find on the band
- Weak signal. SSB, CW and digital modes gather around 5760.100 MHz in North America and 5760.200 MHz in IARU Region 1, with beacons close by.[7][8] Moonbounce operators use the same part of the band, and Region 1 also has a narrowband area around 5668.200 MHz.[7][8]
- Satellites. International and US rules set aside 5650–5670 MHz for uplinks from Earth to amateur satellites and 5830–5850 MHz for downlinks from them.[9][10]
- Data networks. The 5.8 GHz band is the most widely used band for AREDN mesh links in the US, with many channels and compact high-gain antennas. Similar amateur data networks run elsewhere where national rules allow.
- Amateur television. The band has room for wideband analog and digital video signals, used for ATV links and portable cameras.[7]
Propagation
Line-of-sight paths from hilltops are the everyday mode, and tropospheric ducting can carry signals much farther. The band is one of the two best for rain scatter, in which both stations aim at a heavy rain cell and bounce signals off it.[11] Scattering is weaker at 5.7 GHz than at 10 GHz, but the rain also absorbs less of the signal, so the two bands each have their advocates.[11]
Equipment
Most weak-signal stations use a transverter with a 2-meter or 70-centimeter radio, mounted at or near a dish to avoid feed line loss. A few all-in-one radios cover the band, such as Icom's IC-905, which produces 2 watts on its 5600 MHz band.[12] Data stations use outdoor wireless hardware reflashed with amateur firmware.
See also
References
- ↑ 1.0 1.1 1.2 1.3 47 CFR 97.301, eCFR.
- ↑ The Microwave Bands, RSGB.
- ↑ 3.0 3.1 3.2 3.3 47 CFR 97.303, eCFR.
- ↑ 5.7 and 10 GHz band plan, RSGB.
- ↑ 5.0 5.1 Table of Frequency Allocations: SHF, ITU.
- ↑ 6.0 6.1 Use of the 5.850-5.925 GHz Band, Federal Register, May 2021.
- ↑ 7.0 7.1 7.2 Band Plan, ARRL.
- ↑ 8.0 8.1 IARU Region 1 SHF band plan, IARU Region 1, December 2020.
- ↑ 47 CFR 97.209, eCFR.
- ↑ 47 CFR 97.207, eCFR.
- ↑ 11.0 11.1 Rain Scatter Propagation, RSGB.
- ↑ IC-905, Icom America.