Hey Guys,
Just curious, does RDS work on part 15 FM & AM?
Also does it require extra hardware or maybe just use the rds function on the Stereo Tool plugin?
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Comments
Carl Blaresays
Shared Thoughts I know only enough to speculate, but that’s a start.
The Part 15 Rules do not restrict content of legal signals, therefore RDS (Radio Data System) could be added to an AM main carrier with a 5KHz bandwidth limit. A subcarrier on AM would probably by possible but it would most likely be audible as a high pitch and have very narrow bandwidth, requiring extra low speed data transmission.
On FM data could be added to the main carrier with a wide 100KHz bandwidth, or a sub-carrier could be injected at the standard (for RDS) 57KHz which would achieve industry standard RDS transmission.
The engineering needed to modify Part 15 transmitters might be addressed by other commentors.
Interesting subject.
Carl Blaresays
Stereo Tool Possibly I use Stereo Tool but do not have the FM function.
If the Stereo Tool plugin is designed to generate a pilot tone at 57KHz then it would only work straight into an FM transmitter’s main channel audio input if the stereo pilot and stereo sub-carrier where turned off and the low-pass filtering of the audio channel were bypassed putting the transmitter in a strictly mono-mode so that the injected 57KHz RDS signal would enter un-attenuated.
To layer it on top of the stereo capacity I think you’d need to know how it is done in the case of professional FM stereo modulators which might require a piece of RDS equipment.
But it could be done.
This is a best guess.
MICRO1700says
RDS on FM Hi there!
I believe RDS has always just been on FM, and
that it was being used widely in Europe by
commercial broadcasters before it really
caught on with licensed broadcasters here in the
U.S. People who try to listen to distant FM
stations as a hobby like RDS because it can
sometimes aid in identification of the target
station.
This is just a guess, but I do not think it is
possible to use RDS with an FCC type
accepted FM transmitter. I may be completely wrong
about this, but it seems to me that most
or all FCC type accepted FM transmitters are
transmitting the audio spectrum, which is
roughly 20 hz to 20 khz. I don’t have any
idea what part of the spectrum the RDS
coding uses, but anybody could Google that
and probably find out right away. My guess is
that the RDS used spectrum is higher than 20 Khz.
It also seems to me that the transmitter would
also need some kind of encoder to handle the
information. I have never seen an FCC type
accepted FM transmitter like that.
I really know nothing about this, but it is fun
to talk about it even if it can’t be done, because,
after all, this is engineering, and a lot of people
in the Part 15 “world” either were broadcast
engineers, or still are. Or, in my case – well, I
wanted to be a broadcast engineer, but eye
problems prevented my from becoming one.
That’s why I built a Part 15 station. I’m happy
with my signal just being heard in my house and
yard. My Part 15 station is more like a relic from
the past that transmits through old radios (and
new ones.)
MICRO1700says
RDS on FM Hi Carl! I just read your comments after I
submitted mine. I enjoyed reading about
what you know. It is interesting.
From PCS Electronics:
“The new RDSMAX 4000+ is a high-performance RDS encoder utilizing several on-board DSP processors. RDSMAX 4000+ gives you easy access to a wide array of RDS parameters. ”
“Installing RDS encoder can hardly be easier than this:
– Insert encoder between stereo encoder and FM exciter (or connect it directly to the MPX input)
– Set RDS carrier level and optionally set phase (usually not required)
– Connect power
– Connect RS232 or USB cable (requires optional I/O board), install windows program and start transmitting RDS” RDS MAX 4000+
MICRO1700says
RDS on 1700 Hi Carl and SCWIS and rock95seven and anyone else
I missed.
Well, that’s really something! It’s out there and I
sure didn’t know anything it.
Very cool!
kc8gpdsays
RDS Raises the S/N figures RDS Raises the S/N figures just like FM Stereo does, as such it requires a higher signal strength to get the same range results as FM mono.
Shared Thoughts
I know only enough to speculate, but that’s a start.
The Part 15 Rules do not restrict content of legal signals, therefore RDS (Radio Data System) could be added to an AM main carrier with a 5KHz bandwidth limit. A subcarrier on AM would probably by possible but it would most likely be audible as a high pitch and have very narrow bandwidth, requiring extra low speed data transmission.
On FM data could be added to the main carrier with a wide 100KHz bandwidth, or a sub-carrier could be injected at the standard (for RDS) 57KHz which would achieve industry standard RDS transmission.
The engineering needed to modify Part 15 transmitters might be addressed by other commentors.
Interesting subject.
Stereo Tool Possibly
I use Stereo Tool but do not have the FM function.
If the Stereo Tool plugin is designed to generate a pilot tone at 57KHz then it would only work straight into an FM transmitter’s main channel audio input if the stereo pilot and stereo sub-carrier where turned off and the low-pass filtering of the audio channel were bypassed putting the transmitter in a strictly mono-mode so that the injected 57KHz RDS signal would enter un-attenuated.
To layer it on top of the stereo capacity I think you’d need to know how it is done in the case of professional FM stereo modulators which might require a piece of RDS equipment.
But it could be done.
This is a best guess.
RDS on FM
Hi there!
I believe RDS has always just been on FM, and
that it was being used widely in Europe by
commercial broadcasters before it really
caught on with licensed broadcasters here in the
U.S. People who try to listen to distant FM
stations as a hobby like RDS because it can
sometimes aid in identification of the target
station.
This is just a guess, but I do not think it is
possible to use RDS with an FCC type
accepted FM transmitter. I may be completely wrong
about this, but it seems to me that most
or all FCC type accepted FM transmitters are
transmitting the audio spectrum, which is
roughly 20 hz to 20 khz. I don’t have any
idea what part of the spectrum the RDS
coding uses, but anybody could Google that
and probably find out right away. My guess is
that the RDS used spectrum is higher than 20 Khz.
It also seems to me that the transmitter would
also need some kind of encoder to handle the
information. I have never seen an FCC type
accepted FM transmitter like that.
I really know nothing about this, but it is fun
to talk about it even if it can’t be done, because,
after all, this is engineering, and a lot of people
in the Part 15 “world” either were broadcast
engineers, or still are. Or, in my case – well, I
wanted to be a broadcast engineer, but eye
problems prevented my from becoming one.
That’s why I built a Part 15 station. I’m happy
with my signal just being heard in my house and
yard. My Part 15 station is more like a relic from
the past that transmits through old radios (and
new ones.)
RDS on FM
Hi Carl! I just read your comments after I
submitted mine. I enjoyed reading about
what you know. It is interesting.
RDS Wikipedia Link
Thank you MICRO1700
Here’s an informative link
http://en.wikipedia.org/wiki/Radio_Data_System
OTS RDS Add-on
RDS MAX 4000+
From PCS Electronics:
“The new RDSMAX 4000+ is a high-performance RDS encoder utilizing several on-board DSP processors. RDSMAX 4000+ gives you easy access to a wide array of RDS parameters. ”
“Installing RDS encoder can hardly be easier than this:
– Insert encoder between stereo encoder and FM exciter (or connect it directly to the MPX input)
– Set RDS carrier level and optionally set phase (usually not required)
– Connect power
– Connect RS232 or USB cable (requires optional I/O board), install windows program and start transmitting RDS”
RDS MAX 4000+
RDS on 1700
Hi Carl and SCWIS and rock95seven and anyone else
I missed.
Well, that’s really something! It’s out there and I
sure didn’t know anything it.
Very cool!
RDS Raises the S/N figures
RDS Raises the S/N figures just like FM Stereo does, as such it requires a higher signal strength to get the same range results as FM mono.