Learn / Guide 6
Shortwave DX
Broadcast bands in meters, schedules in UTC, the SINPO code, and how to request a QSL card from a broadcaster.
intermediate 6 min read
What doing broadcaster DX is
DX, in radio listening, means hearing a distant or difficult station and logging the reception. Shortwave is the classic terrain, because there a station from another continent arrives sounding like a kitchen radio.
The bands, in meters
Broadcasters concentrate in bands defined by the ITU and identified by wavelength.
| Band | Frequency (kHz) | When it pays off |
|---|---|---|
| 120 m | 2,300 to 2,495 | night; tropical band |
| 90 m | 3,200 to 3,400 | night; tropical band |
| 60 m | 4,750 to 5,060 | night; tropical band |
| 49 m | 5,900 to 6,200 | night |
| 41 m | 7,200 to 7,450 | night (in the Americas, 7,200 to 7,300 is amateur radio) |
| 31 m | 9,400 to 9,900 | late afternoon, night, and dawn |
| 25 m | 11,600 to 12,100 | day and early evening |
| 22 m | 13,570 to 13,870 | day |
| 19 m | 15,100 to 15,800 | day |
| 16 m | 17,480 to 17,900 | day |
| 13 m | 21,450 to 21,850 | day, with active Sun |
Channels are spaced every 5 kHz. If you found a carrier at 9.667, the channel is 9.665 and the difference is a tuning or transmitter error.
Tropical bands were created for countries where static makes medium wave poor.
Time is in UTC
Every shortwave schedule uses UTC, universal time. Brasília is three hours behind, all year round.
| UTC | Brasilia |
|---|---|
| 00:00 | 21:00 of the previous day |
| 12:00 | 09:00 |
| 21:00 | 18:00 |
Pay attention to the day changeover. A listening session at 10 PM on Tuesday in São Bernardo is 01:00 UTC on Wednesday, and that is how it goes into the logbook.
Stations change frequency twice a year, on the last Sunday of March and the last Sunday of October, to follow propagation. The seasons are called A (mid-year) and B (turn of the year). A frequency list from a year ago may be completely wrong.
What reaches Brazil well
I will give names without pinning down frequencies, because the schedule changes every season.
- National Radio of Amazonia. The Brazilian public shortwave broadcaster, made for the Northern region. Listeners still log it on 11,780 and 6,180 kHz in 2026, but schedules changed mid-year and the old transmitter sometimes goes off the air. Check a current schedule before looking.
- Religious and commercial stations of the United States. They transmit with high power to the Americas and tend to be the strongest on the band.
- International services from other countries. Several still broadcast to South America, in Spanish, in English, and some in Portuguese. The list has shrunk in recent years and changes every season, so check the schedule instead of trusting an old list.
- Time signal stations. WWV from Colorado on 2,500, 5,000, 10,000, 15,000 and 20,000 kHz, and WWVH from Hawaii on the first four. WWV also has an experimental transmission on 25,000 kHz. They are the best propagation ruler that exists. On WWV the time is announced by a male voice, and on WWVH by a female voice.
To know what is on the air now, use a schedule site like Short-Wave.info (search by frequency or station) or the EiBi list, maintained by a listener and updated every season. HFCC publishes the official coordination among stations.
Listen on a remote receiver
Choose one KiwiSDR in Brazil if the idea is to know what arrives here. Use AM mode with a 6 to 10 kHz filter.
Two tricks for difficult signals:
- If a neighboring station is interfering from one side, switch to USB or LSB, tune exactly to the carrier, and listen only to the clean sideband.
- If the audio distorts when the signal fades, try synchronous AM (SAM) mode, which many receivers have. It holds the carrier during fading.
Confirm the identity of the broadcaster before making a note. The announcement usually comes at the top and bottom of the hour, with name, country and sometimes a musical interval signal.
The SINPO code
SINPO is the standard way to report how a broadcast arrived. It consists of five scores, from 1 to 5, with 5 always being the best.
| Letter | What it evaluates | Note 5 | Note 1 |
|---|---|---|---|
| S | signal strength | excellent | barely audible |
| I | interference from other stations | none | extreme |
| N | noise (static, electrical noise) | none | extreme |
| P | propagation disturbance (fading) | none | extreme |
| The | general evaluation | excellent | unusable |
A SINPO 45444 describes a strong signal, without interference, with low noise and mild fading. 55555 almost never happens, and a report full of fives loses credibility.
Reception report and QSL card
The reception report is a letter, nowadays almost always an email, in which you tell the broadcaster how it came in. In return, many send a QSL card, which confirms the listening.
A good report has:
- Start and end date and time, in UTC.
- Frequency in kHz.
- SINPO, preferably at two or three moments.
- Program details that prove you listened: announcer's name, subject, a song, an advertisement. About 15 minutes of details are enough.
- Your receiver, your antenna and the location.
Be honest about the receiver. If the listening was done via a KiwiSDR, state that and report the city where it is located. What matters to the station is where the signal arrived. Some confirm remote listening, others do not, and pretending it was at your house ruins the QSL card's value for everyone.