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RDS question

D

dxer720

I know this in not exactly HD radio, but I couldn't think of a better place to post this. If a better board can be found, please move it.

How many text layers are there in the RDS system?

I have a Sangean ATS-909 portable with RDS & 2002 Chevy Malibu CD/radio which also has RDS.

The Sangean only displays the text in all caps as it's incapable of displaying lower cases.

The car radio offers not only lower case text, but is also able to use the format codes & other RDS features.

I recently got an MP3 player with an FM tuner that displays RDS. It displays 2 lines of text. The top line is the same 8-character per screen display my other radios show. What I'm wondering about is what I get on the lower line. On some stations this line will display longer messages up to 32 characters. This 2nd line is not a longer version of the first line, either. The messages are completely different.

Example for WIIL 95.1 Kenosha, WI

Top: "WIIL-FM"
Bottom: "Tom & Lisa mornings 95 WIIL Rock Thee Rock Station"

My other 2 RDS-capible radios only display the top text.

Have these "bottom" messages been added to RDS after the other 2 radios' manufacture, or are these receivers missing something that can be corrected?
 
Hi

What you're seeing is the radiotext (R/T) feature. Only some RDS receivers show this. Most stations will just use it for a slogan but others use it to show song title/Artist info. There are only the two layers of text. The other fields that RDS shows is a clock, Program Type (eg Rock Music) & the PI code. RDS has other functions which are not related to the display such as AF (Alternative Frequency) which can be used for FM networks where you run multiple frequencies (ie translators).

dxer2_2000
 
Thanx dxer2_2000. I have used the clock setting function on both the Sangean & the car radio. I've also used the program type function on the car radio. What is the PI code & what does it do?

BTW: I was surprised to find my new Insignia Sport MP3 player was able to use RDS in addition to all its other functions. All for $40.
 
dxer720 said:
What is the PI code & what does it do?
Click to expand...

The 16-bit PI (Program Identification) code is unique to each station or regional "network", is based on the primary station's callsign, and is included in every group and transmitted more frequently than any other RDS code. You might think of it as a station's "DNA".

It assists in the receivers' automatic retuning function as a means to verify that an alternate frequency signal (such as a translator) is actually a simulcast of the primary. After retuning, the receiver must see a match, otherwise it will revert to the original frequency.
 
More information on RDS can be found on Wikipedia's article.

http://en.wikipedia.org/wiki/Radio_Data_System

Personally, I think RDS + well processed analog can be just as good as HD radio (see, I'm keeping it topical).

In fact, I've noticed most HD stations also do RDS as a "fallback" for those areas where HD doesn't work. I used to have a Kenwood car stereo with RDS and it made DXing really fun. Right now I've got the Radio Shack equivalent of your Sangean and a SonyEricsson phone, which does RDS with support for the AF alt. frequency thing (which works nicely on our state's public radio network.)
 
Zach said:
Right now I've got the Radio Shack equivalent of your Sangean and a SonyEricsson phone, which does RDS with support for the AF alt. frequency thing (which works nicely on our state's public radio network.)
Click to expand...

I'm happy to hear that your public network is taking advantage of the AF function. This is a feature many domestic broadcasters have overlooked, but it could be very helpful to listeners of the simulcast FM "networks" which are growing in number. The Wilkes-Barre/Scranton PA market, for instance, now has several commercial stations simulcasting on alternate frequencies to cover population spread across a long valley.

I've driven rental cars in Germany which had AF (it's a standard feature on most European models) and it works very well.

Now why doesn't HD Radio offer an AF function? This would seem to be a big step backwards -- but I guess I'm not surprised, considering how many other aspects of the system the developers got wrong.
 
Play Freebird said:
I'm happy to hear that your public network is taking advantage of the AF function. This is a feature many domestic broadcasters have overlooked, but it could be very helpful to listeners of the simulcast FM "networks" which are growing in number. The Wilkes-Barre/Scranton PA market, for instance, now has several commercial stations simulcasting on alternate frequencies to cover population spread across a long valley.

I've driven rental cars in Germany which had AF (it's a standard feature on most European models) and it works very well.

Now why doesn't HD Radio offer an AF function? This would seem to be a big step backwards -- but I guess I'm not surprised, considering how many other aspects of the system the developers got wrong.
Click to expand...

I don't see why HD radios can't still decode that part of the RDS stream while also decoding HD, but like you said there's a lot the developers got wrong.

We also have a nearly-statewide talk radio network on FM, who doesn't use AF even though many of the stations have RDS enabled. Seems like it would in the best interest of these networks to assist listeners in staying as long as possible, especially for us "fringe listeners" who have to bounce around 2-3 different frequencies to stay in touch.

Of course, us "fringe listeners" have no use of HD. ;)

Now what bothers me about AF on our public radio network is some stations are doing HD, some are not. So in the middle of a program it may switch to another frequency and I lose 6 seconds of audio, then back again and I hear the same thing twice. D'oh.
 
What really bewilders me is the fact that the ABC (Australian Broadcasting Corporation) doesn't transmit RDS & make use of the AF function. Considering it has 5 radio networks across this vast country of ours.....Most transmitters being FM too.

dxer2_2000
 
As an aside to this discussion, you might find this announcement of interest:

"Song Tagging Technology Comes To FM Radio"

"A group of nine broadcast companies have announced their commitment to providing electronic data that will enable consumers to tag songs they hear on FM radio for immediate purchase bringing the music discovery and purchase processes closer together than ever. The first device to make use of this data will be the Microsoft Zune as part of a new set of features for the MP3 player."

The technology utilizes RDS coding to do this.

http://www.radioandrecords.com/RRWebSite/

C5
 
Carmine5 said:
As an aside to this discussion, you might find this announcement of interest:

"Song Tagging Technology Comes To FM Radio"

"A group of nine broadcast companies have announced their commitment to providing electronic data that will enable consumers to tag songs they hear on FM radio for immediate purchase bringing the music discovery and purchase processes closer together than ever. The first device to make use of this data will be the Microsoft Zune as part of a new set of features for the MP3 player."

The technology utilizes RDS coding to do this.

http://www.radioandrecords.com/RRWebSite/
Click to expand...

See, this is why the proprietary HD Radio system is doomed for failure.

Microsoft wants to sell Zunes to a world market, so they based the tagging feature on FM and RDS, both open standards. Why should broadcasters be forced to turn over a portion of tagging revenue to Mr. Bickwitty (as required under his HD license agreement) when RDS is practically free and more reliable?

I expect Apple will offer a similar feature in future iPods.
 
My $40 Insignia Sport MP3 player arleady does this. The only part missing is the WIFI downloading. Just 3 steps & you have the song.

1. Tag the song on the RBDS of the player's FM tuner.
2. Connect to computer.
3. Download.

It's worked 2 out of 3 times i tried it. Te one time it didn't work was because the radio station used te word "and" instead of the "&" symbol. The tag from the radio didn't match the title in the computer's database. I found & downloaded the song, but it wasn't automatic because of the missmatch.

I suppose the same thing could happen if one or more characters weren't received properly.
 
I'm assuming it grabs the song title from the radio text field, which many stations already use for song title/artist info, even though very few radios in the US show the text field.

Once again free and open beats closed and proprietary. ;)
 
Yes, Zach. It does. It will even display both RDS layers simultaniously. Of my 3 RDS-capible radios, its the only one to handle RadioText.

Another one of HD radio's "features" shot down.
 
Play Freebird said:



I expect Apple will offer a similar feature in future iPods.
Click to expand...

If you're thinking that Apple will put an FM radio in an iPod like the Zune, I highly doubt we'll ever see it. Apple seems totally focused on creating products for downloading and playing web-delivered content.

Look at the Apple TV Take 2. One of it's key features, besides managing one's personal digital library, is providing an interface between internet content and a home entertainment system (BTW, this includes playing web radio through a home stereo system).

What we might see, and this totally doable, is a tagging feature for internet radio. We're just talking software here, either from Apple or a third party. And this feature could work on BlackBerrys and other smartphones as well as the iPhone and iPod Touch.

But again, as you observed, no need for HD Radio.

C5
 
Carmine5 said:
But again, as you observed, no need for HD Radio.
Click to expand...

HD Radio already did the exact same deal about 4 months ago. And the usual folks attacked it as a bad idea.

So song tagging is now available for both HD and FM.
 
TheBigA said:
HD Radio already did the exact same deal about 4 months ago. And the usual folks attacked it as a bad idea.
Click to expand...

Not quite the "exact same" deal; HD receivers require the iPod to be physically docked to a table radio, but the Zune allows a listener to tag a song on the go and immediately download it via WiFi to the same device. If the Zune is out of wireless range, it will complete the process as soon as it finds an open network -- the user doesn't need to remember to dock or do anything out of the ordinary.

When tagging was first announced for HD, I happened to think it was a good idea, but the problems have been in the convenience and expense (for example, the Polk tagging receiver lists for nearly $500). The Zune's FM RDS tagging feature is much less cumbersome, royalty-free, and a fraction of the cost.

By the way, Apple does offer a plug-in FM adapter with RDS for the iPod but I've heard it doesn't perform very well.

http://ipod.about.com/od/misc/tp/fm_tuners.htm

Now, all we need is an update to the RDS protocol to allow a station to transmit the URL of its Internet stream.
 
Hey Play Freebird, the lame Cumulus stations here installed HD at all their FM's (no AM's), but none have any PAD info, just their web address, so I guess that's better than nothing - but I'd rather have song titles and artists.
 
Play Freebird said:
By the way, Apple does offer a plug-in FM adapter with RDS for the iPod but I've heard it doesn't perform very well.
Click to expand...

When I tried the Zune FM tuner in their first model, it didn't seem to receive stations very well. The tuning dial is small, and there's not much of an antenna. Don't know about this new model.
 
TheBigA said:
When I tried the Zune FM tuner in their first model, it didn't seem to receive stations very well. The tuning dial is small, and there's not much of an antenna. Don't know about this new model.
Click to expand...

The reviews I've found are divided between "really good" and "really bad", so I'm not sure who to believe. Of course, like most small FM receivers, it uses the headphone cord as the antenna so that would indeed make a difference.

Amazon's price on the 4 GB "2nd gen" version is down to $107 so I may pick one up. I've been told there's a hack that allows normally-hidden RDS data to be displayed, so it could be useful as a piece of "test equipment".
 
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