MA3 Bitrate and HD2 support.

[tsalisbury0]

MA3 according to some documents supports up to 20-40kbps audio depending on how much data is sent as well as HD2 support.

[argilo]

To support higher bit rates, it will be necessary to implement support for the "enhanced" stream. Some work has gone into adding decoding support in theori-io/nrsc5#245, but it doesn't yet work. If someone gets that working, I may take a crack at adding the necessary support into gr-nrsc5.

I did once try to send an HD2 program, but couldn't get it to work with either of my receivers at the time (HDR-14, HDT-20). Either they don't support HD2, or I messed up somewhere. I now have an SHD-T750 as well, so I might someday take another crack at it.

Are any AM stations known to have an HD2? If so, I'd love to get a recording.

[tsalisbury0]

WSHE 820 randomly test HD2.

[argilo]

WSHE 820 randomly test HD2.

Neat. I would definitely love to get an I/Q recording if you or someone else manages to catch it with HD2 running.

[argilo]

I tried again to put an HD2 program into the P3 logical channel, in both AM service modes (MA1 and MA3). Unfortunately it didn't work with the SPARC receiver. It briefly showed HD1+ as if there was a second program, but quickly reverted to showing only HD1.

I also tried sending a station logo in the P3 logical channel, and that worked fine. So it seems likely that the P3 logical channel is working properly in gr-nrsc5, but there could still be a bug somewhere else, perhaps in layer 2. Or the receiver could be at fault, but I'd say that's less likely.

A recording of WSHE with HD2 running would be most helpful.

[argilo]

Or the receiver could be at fault, but I'd say that's less likely.

Then again, this article from 2019 states that radios of the time were not able to receive HD2:

https://www.fybush.com/nerw-extra-hd2-arrives-on-am-radio/

[Sussyman2-0]

I tried again to put an HD2 program into the P3 logical channel, in both AM service modes (MA1 and MA3). Unfortunately it didn't work with the SPARC receiver. It briefly showed HD1+ as if there was a second program, but quickly reverted to showing only HD1.

I also tried sending a station logo in the P3 logical channel, and that worked fine. So it seems likely that the P3 logical channel is working properly in gr-nrsc5, but there could still be a bug somewhere else, perhaps in layer 2. Or the receiver could be at fault, but I'd say that's less likely.

A recording of WSHE with HD2 running would be most helpful.

I was testing on a Pioneer AVH-601EX, which the manual states around 2017, and the radio was released early 2018. i don't know if pioneer added support for MA3 with the P3 logical channel. P1 does work, but Ive even tried pushing 2 programs into the P1 logical channel, no dice.

[argilo]

Ive even tried pushing 2 programs into the P1 logical channel, no dice.

Yeah, I've tried that as well. Both MA3 and the P3 logical channel seem to be well supported, but receivers simply don't allow more than one program on AM.