The shortwave range in brief
Shortwave is generally defined as the radio spectrum from about 3 MHz to 30 MHz, which is the HF (high frequency) range. In wavelength terms that is roughly 100 metres down to 10 metres. Many consumer receivers and some definitions start lower, at about 1.6 to 2 MHz, so that they include the 120 metre broadcast band and the nearby 160 metre amateur band. Exact edges vary by source, so treat the boundaries as approximate.
Shortwave signals can travel far because the ionosphere can refract them back to Earth. How far and when depends on frequency, time of day and solar activity; see how far a shortwave radio can reach.
Shortwave broadcast bands
Broadcasters use blocks of spectrum named after their approximate wavelength in metres. The figures below are approximate; actual allocations are set internationally and can differ slightly by region, and use changes over time, so confirm in a current band plan.
| Band | Approximate range (MHz) |
|---|---|
| 120 m | 2.3 - 2.5 |
| 90 m | 3.2 - 3.4 |
| 75 m | 3.9 - 4.0 |
| 60 m | 4.75 - 5.06 |
| 49 m | 5.9 - 6.2 |
| 41 m | 7.2 - 7.45 |
| 31 m | 9.4 - 9.9 |
| 25 m | 11.6 - 12.1 |
| 22 m | 13.57 - 13.87 |
| 19 m | 15.1 - 15.8 |
| 16 m | 17.48 - 17.9 |
| 13 m | 21.45 - 21.85 |
| 11 m | 25.67 - 26.1 |
Ham radio bands inside shortwave
Amateur radio operators have their own HF allocations, which are separate from the broadcast bands. Common ones include roughly:
- 80 m: 3.5 - 4.0 MHz (portion varies by country)
- 40 m: 7.0 - 7.3 MHz (varies by region)
- 30 m: 10.1 - 10.15 MHz
- 20 m: 14.0 - 14.35 MHz
- 17 m: 18.068 - 18.168 MHz
- 15 m: 21.0 - 21.45 MHz
- 12 m: 24.89 - 24.99 MHz
- 10 m: 28.0 - 29.7 MHz
Which parts of each band you may use depends on your country, license class (see Extra class privileges) and mode. Check your national regulator, and see ham radio regions and ITU zones for why allocations differ. For how amateur use differs from broadcast listening, read the difference between shortwave and ham radio.
Other services in the range
Between broadcast and ham allocations sit aviation, maritime, time-signal, military, government and other services. Time stations such as WWV in the United States use frequencies like 5, 10 and 15 MHz, among others. Much of this traffic is not intended for casual broadcast listening and may be encrypted or digital.
Which frequencies work when
As a general pattern, lower shortwave bands (below about 10 MHz) tend to work better at night, and higher bands (above about 10 to 15 MHz) tend to work better during daylight. This is a rule of thumb: the higher bands can be open for long periods when solar activity is higher, and conditions shift with the seasons and the solar cycle.
What about 136-174 MHz?
This is not shortwave. It lies in the VHF range, well above 30 MHz. Within it you will find services such as two-way land mobile radio, public safety and marine channels in many places, plus the amateur 2 metre band (see VHF vs UHF for hams) (144 to 148 MHz in many regions, with variations elsewhere). These signals mainly travel line-of-sight rather than over long skywave paths, so they need different antennas and are used for local communication. Local allocations differ, so check a regional band plan.
How to listen
- Set a clock to UTC, since schedules use it.
- Find a current broadcast schedule for the region and time you want.
- Tune to the listed frequency with a receiver that covers the band.
- Try different antennas and locations if the signal is weak or noisy.
If you have never listened before, what shortwave radio is good for explains what to expect.