The Radio Broadcast Data System (RBDS),1 as it is called in the North America, or simply RDS in the rest of the world, is a protocol for embedding data in an FM/VHF broadcast. The data can include the station name, program content and even the time of day. I have three radios that display some of this information on the FM band, some better than others.
RDS Data is divided into segments, some of which are displayed on one or more of my radios:
- PS: Program Service Name – may identify the station
- PTY: Program Type – comes from a fixed list including things line NEWS or SPORTS
- RT: Radio Text – this is a 64-character string of text that could provide more information about the station, program, or the title and artist of a song being played
- DATA or CT: Time and date. May also include station call sign.
- PI: Program identification: identifies the station with a regionally unique 4-digit hexadecimal number. Codes for the US can be found at the National Radio Systems Committee page.
It would seem that there are three practical uses for the radio enthusiast:
- Identifying the station
- Identifying the program content
- Setting a clock
Features and differences
Here are my three radios and what they can do:
| Segment/feature | Eton Elite Executive | Qodosen SR-286 | XHDATA D-808 |
|---|---|---|---|
| PS | Y | Y | Y |
| PTY | Y | Y | Y |
| RT | Y | Y | Y |
| DATA | Y | Y | Y |
| PI | Y | ||
| Set clock | Y | Y | Y |
| RDS/RBDS setting | Y | ||
| RDS Off/On | Y |
Clock setting for these radios is either Manual or Automatic. In Automatic mode, each of these radios automatically sets the clock from RDS data when it is received. I consider the feature useless because stations do not always have the right time; for example, one local station didn’t “spring forward” and update their time for Daylight Savings Time.
Each radio has a button to select which segment is displayed. It’s the [R·D·S] button on the SR-286, [RDS MODE] on the Elite Executive and [INFO] on the D-808. The RDS feature has to be turned on explicitly on the Elite Executive by pressing the [RDS] button.
RDS vs RBDS
Differences exist between the two implementations; for example, the DATA segment is supposed to indicate the station call sign in RBDS, but not RDS. Also the Program Type codes are different.
Only the Qodosen SR-286 has an explicit setting for the mode. We’ll test to see if the other radios figure it out correctly. The Wikipedia article footnoted at the end has full technical details.
Testing
Testing is made more complicated by the need for a strong signal to get RDS information, inconsistencies in what radio stations actually include and the fact that information is not always available immediately. It may require a one-minute wait for the DATA segment to be broadcast during which the radio may display “NO DATA” (the D-808 will display “NO DATE”). I was misled to think none of my local stations had time data by not waiting long enough.
Note: the SR-286 manual has a mistake, saying that repeated presses of the [R·D·S] button cycle through PS/PTY/RT/DATA/PI. It actually displays them in the order, PTY/PS/RT/DATA/PI.
PS Segment
