Solving the Porsche Conundrum

More advanced receivers will sometimes change stations at “random” while the vehicle is in motion, if the same PI code is used by multiple stations
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I perhaps like you, take RDS somewhat for granted here in the US.

RDS has become standard fare for FM stations, especially over the last 10 years.

RDS has become standard fare for FM stations, especially over the last 10 years.

In most cases, we connect a serial or Ethernet data stream from our playout system (by some means) to our RDS generator at the transmitter and observe title and artist/promotion information displayed on the receiver. At its root, it is a fairly straight forward system.

In Europe, the RDS system is utilized in a far more expanded scope — they mean business with RDS in Europe. It's actually a shame we often don't use its full capabilities here (although some do, for sure) but perhaps due in part to the sheer number of stations and the expanse of the US, it doesn't have the same applications here.

The other day, I received a phone call from a customer service manager at a local Porsche dealer, who wondered if I was having any unusual problems with two of my stations. I replied that, to the best of my knowledge, we were 100 percent. Within a few minutes, I learned some of the dealership's customers were complaining that there was a problem in the car receivers that resulted in seemingly random switching from one of my stations to another.

At first, my reaction was huh! But then I recalled that in Europe (where the Porsche is manufactured with Becker receivers installed) how big a deal RDS is, and this suggested a connection.

I checked the RDS encoders on these two stations (one of which is a translator — more on that in a moment) and found, to my surprise, that the PI codes for both were at the default PI code of "F000."

I know better than to leave these at default, but I recalled one of these encoders was recently updated with the latest firmware. While I am sure I entered the proper PI code, perhaps I didn't click the "update" button (who knows?). I really don't know why the translator RDS generator wasn't set — I never had occasion to look at it, and this was installed before I accepted the position.

In any case, it turns out that more advanced receivers (particularly those with advanced RDS capabilities) will sometimes change stations at "random" while the vehicle is in motion, if the same PI code is used by multiple stations. Doubtless, many customers have taken their cars back to the dealership, complaining of "faulty receivers" (as was the case with the local Porsche dealer) in areas with RDS PI code duplications.

Also, consider the scenario in which a station has a backup transmitter that sees only infrequent use but has the default PI code of F000 selected in that site's RDS encoder. When that site is in-use, and another station's encoder is set to default as well, this can lead to a confusing situation indeed. Once I discovered the issue, I corrected it from the comfort of my desk — and all issues were resolved.


Now to the translator I referenced earlier: The proper PI code is somewhat muddied and can be a bit confusing. As you may know, the PI code is generated based upon a four-letter call sign using an on-line applet, one of which is available at

For example, WKHK will lead a PI code of 6FD0, but what to do about the translator call signs such as W291CL? This is not so much an issue for those stations use the translator to repeat a parent station's programming, but what about when used as a translator for an HD2/HD3 format, which is likely unrelated in any fashion to the parent station's format?

I have researched the matter with several RDS experts and found some general guidelines (although no hard and fast rules).

Suggestions vary from make something up which isn't already in-use to change your station's call letters from a leading "W" to a "K" (or vice-versa). What I have chosen to do is to take the first four call letters of the translator (W291 in the example above truncating the "CL") and generate a code. If someone has a better idea or has different information, please send an email to

So check those PI codes at any site with an RDS generator and avoid your own "Porsche conundrum."

Dennis Sloatman is the director of engineering and IT for Summit Media's Richmond, Va., stations.