160-meter band
| 160-meter band | |
|---|---|
| Frequency range | 1.800–2.000 MHz (US); narrower in many other countries |
| Wavelength | About 160 m |
| Group | MF |
| US license | General and above, the whole band; no Technician privileges |
| Operating | |
| Common modes | CW, FT8, SSB (lower sideband) |
| FT8 frequency | 1.840 MHz |
| Half-wave dipole length | About 250 feet (76 m) |
| Quarter-wave vertical height | About 125 feet (38 m) |
| Best time | Winter nights, especially around sunset and sunrise |
The 160-meter band, 1.800 to 2.000 MHz, is the lowest of the traditional amateur bands; only the newer, specialized 630-meter and 2200-meter bands lie below it. Known to its regulars as top band, it sits just above the AM broadcast band and behaves much like it: short range by day, long distance after dark. Antennas are enormous, noise is fierce and signals are often weak, and for many experienced operators that challenge is exactly the appeal.
Propagation
By day the D layer of the ionosphere absorbs 160-meter skywave almost completely, leaving only ground wave, good for regional contacts of a few tens of miles. After dark the absorption fades and signals refract from the higher layers, first across a region and then, as darkness spreads, across a continent or an ocean. Long-distance contacts need darkness over most of the path, so the best intercontinental openings tend to come around local sunset and sunrise, when one end of the path is just entering or leaving the night.
Winter is the season. Nights are long, and the static from thunderstorms that plagues summer evenings dies away. Unlike the higher bands, 160 meters often does better in the quiet years of the solar cycle, when absorption is lower and geomagnetic disturbances are fewer. Even in a good season, conditions change from night to night, and a path that was wide open yesterday may be silent today.
What you'll find on the band
The FCC does not divide 160 meters by mode: any licensee with privileges here may use CW, voice, data or image anywhere in the band. The voluntary band plan keeps order instead:
- CW occupies the lower part of the band, where most DX and contest activity takes place.
- FT8 sits at 1.840 MHz. It has brought many stations with modest antennas onto the band, since it decodes signals far too weak to hear.
- Voice, on lower sideband and some AM, is found higher up, generally above about 1.843 MHz.
Allocations in other countries are often narrower and sometimes split into pieces, so DX stations frequently transmit on one frequency and listen on another. Winter weekends bring dedicated 160-meter contests, when the band fills with CW signals.
US privileges
All of 1.800–2.000 MHz is available to General, Advanced and Amateur Extra licensees, at up to 1,500 watts PEP. Holders of all three classes have identical privileges here, so the band is one of the main additions a General license brings. Technicians have no 160-meter transmitting privileges, although nothing stops them from listening.
Antennas
This is where 160 meters earns its reputation. A half-wave dipole is about 250 feet long, and to radiate well at the low angles that long-distance contacts need it would have to be well over 100 feet high, so a dipole at ordinary heights is mainly a regional antenna. Most serious stations use a vertical of some kind:
- A full-size quarter-wave vertical is about 125 feet tall, a project for a tower. Some operators feed an existing tower directly, a technique called shunt feeding.
- The inverted-L is the popular compromise: a wire goes up as high as possible, then turns and runs horizontally to make up the rest of a quarter wavelength.
- Any vertical on 160 meters depends on its ground system. As many radials as the yard allows separate an efficient antenna from one that mostly warms the soil.
Transmitting verticals are noisy to listen on, so many 160-meter operators add separate receiving antennas: small loops, or the Beverage, a wire several hundred feet long strung a few feet above the ground and aimed toward the part of the world the operator wants to hear. Antennas this tall also deserve careful grounding and lightning protection.