Dial frequency versus audio frequency
Most digital modes on HF are sent in upper sideband (USB). The frequency you set on the radio is the dial frequency. The software then places the signal at an audio tone, often somewhere between about 200 and 3000 Hz, so the actual transmitted frequency is the dial frequency plus the audio tone. Published lists nearly always give the dial frequency. Stations gather close to these frequencies so they can find one another.
Frequencies below are commonly used calling frequencies, but they are not rules. Band plans differ between countries and regions and may change, so check your national regulator and your local band plan before transmitting.
FT8 and FT4
| Band | FT8 (MHz) | FT4 (MHz) |
|---|---|---|
| 160 m | 1.840 | varies |
| 80 m | 3.573 | 3.575 |
| 60 m | 5.357 | varies by country |
| 40 m | 7.074 | 7.0475 |
| 30 m | 10.136 | 10.140 |
| 20 m | 14.074 | 14.080 |
| 17 m | 18.100 | 18.104 |
| 15 m | 21.074 | 21.140 |
| 12 m | 24.915 | 24.919 |
| 10 m | 28.074 | 28.180 |
| 6 m | 50.313 | 50.318 |
Treat this table as a starting point and confirm against WSJT-X’s own frequency list, which is kept up to date with the software.
WSPR
WSPR uses its own narrow segments. Typical dial frequencies include 3.5686 MHz (80 m), 7.0386 MHz (40 m), 10.1387 MHz (30 m), 14.0956 MHz (20 m), 18.1046 MHz (17 m), 21.0946 MHz (15 m) and 28.1246 MHz (10 m). The mode is explained in WSPR ham radio.
PSK31, RTTY and other keyboard modes
These modes are less tied to one exact frequency and tend to occupy general digital sub-bands. As approximate guides, PSK31 activity is often found near 14.070 MHz on 20 m and near 7.070 MHz on 40 m, while RTTY activity is common in the lower part of each band, especially around contest periods. JS8Call, a keyboard-style variant built on FT8 technology, is often found near 7.078 and 14.078 MHz. Activity moves around, so tune and watch the waterfall. Digital mode identification shows how to tell them apart.
VHF and UHF data
On VHF and UHF, data use is organized by local band plans. In North America, APRS commonly uses 144.390 MHz, and other regions use different frequencies. Packet networks, DMR repeaters, and mesh networks use their own channels, so check your coordinator or regional plan. See packet radio for hams and mesh network ham radio for more.
What is 136-174 MHz used for?
This range covers the amateur 2-meter band (compared with 70 cm in Is ham radio UHF or VHF?) (144-148 MHz in many regions, and 144-146 MHz in some others), along with a lot of other services. Depending on country, it can include marine radio, business and public safety land mobile radio, and weather or aviation-adjacent services. Only part of it is amateur. Rules differ by region, so rely on your national band plan rather than the broad range.
Software for digital modes
- WSJT-X: FT8, FT4, WSPR and other weak-signal modes.
- JS8Call: keyboard-style messaging based on FT8 technology.
- fldigi: many keyboard modes, including PSK31, RTTY and Olivia.
- Direwolf: software packet TNC for AX.25 and APRS.
- Logging programs: many can connect to the decoder to log contacts.
Will a ham radio pick up police frequencies?
It depends on the radio. Many amateur handhelds can receive beyond the ham bands, and may hear nearby services. Some police systems are digital, trunked or encrypted, which a basic radio cannot decode. Listening rules differ by country and region. Transmitting on non-amateur frequencies is generally not allowed without proper authorization.
Tips
- Check the clock on your computer; FT8, FT4 and WSPR depend on accurate time.
- Use your radio’s USB mode, with minimal audio processing.
- Look at the waterfall before calling (see waterfall software). If an area is busy, wait or choose another frequency.
- When in doubt, consult your national amateur radio organization’s current band plan.