I forgot to mention that there's no free lunch with LDM. Shannon still rules. The SNR of each layer is degraded by the power split. For the vv320.grc example:


re@beavis:~/xfer$ ./ldmsnr 0.3 12.88 4
core snr = 4.170673
enhancement snr = 18.335405


So the QPSK SNR is degraded by about 4 dB and ...

Justin,

I just watched the BATC 26 presentation. Very nice!

Some notes on LDM. First, the atsc3rate program is really only accurate for the single PLP case (as used in the vv031.grc example). The easiest way to calculate bitrates for the more esoteric modes is to use the l1detail feature of the ...

BTW, a software ATSC 3.0 receiver has become available just recently.

https://github.com/adswill/OnAir

Here it is decoding a gr-atsc3 stream.

Justin,

No problem using gr-atsc3 in your project. Always happy to see someone getting some use out of it.

Did you get a regular or development version of the HDHomeRun Flex 4K?

Also, I have a bitrate calculator at:

https://github.com/drmpeg/dtv-utils/blob/master/atsc3rate.c
https://github.com ...

Just FYI, I've been using down converters from the professional side of Kuhne Electronic for my experiments.

https://kuhne.alaris.tech/?aff=7

https://kuhne.alaris.tech/solutions/low-noise-block-down-converters?aff=7

Here's one for 23 cm with a 1000 MHz LO, so 1200 to 1500 MHz -> 200 to 500 MHz ...

Today I learned that you can tune the FLEX 4K to an arbitrary frequency.

For G8YTZ, you may be interested in my ATSC 3.0 transmitter for GNU Radio.

https://github.com/drmpeg/gr-atsc3

It supports all the modes including LDM. Here's an LDM flow graph.

https://www.w6rz.net/atsc3ldmflow.png

It ...

Thanks for the replies. It's really just a convenience factor for me. The FLEX 4K is my primary test receiver, so it would have been nice if it did DVB-T2. I have a Hauppauge PCTV 292e (Si2168 demod) that I use for DVB-T2.

Is it possible to enable DVB-T and DVB-T2 on the HDHomeRun FLEX 4K? It looks like the Sony demod chip is capable.

I guess nobody in the US cares about this except for ham radio operators and experimenters like myself. Maybe just on the developer version?

I'm not sure what this is but it killed my network. I assume it was flooding it, as packet loss was huge, ping times were huge, and I couldn't control the HDHR at all.


It forwards the ATSC 3.0 multicast IP packets onto the LAN (with just the source address and port changed). Probably not a ...

Trip, have you tuned PLP0 via the CLI and set the target to forward and watched either the network rate in Config GUI or monitored via Wireshark to see if there's anything actually on there?

hdhomerun_config xxxxxxxx set /tuner0/channel atsc3:25:0
hdhomerun_config xxxxxxxx set /tuner0/target ...

How are you getting the capture from the HDHR to work?


I'm probably not emulating WNUV close enough. Especially using Transport Streams instead of IP packets. I'll guess the processing path for TS is quite a bit different than IP in the HDHomeRun.

Also, I don't have a universal frame mapper. I ...

I've added CTI to my open source ATSC 3.0 transmitter so that I could run some experiments. I've set up a flow that's similar to the WNUV configuration, but just TDM (not LDM+TDM). But I have used the same parameters for the low bitrate BPS PLP.

The low rate PLP works fine. The data comes out in ...

WNUV could use a 36 (PLP0 and 1) + 1 (PLP16) block HTI configuration and use more cells (and have a higher bitrate on PLP0 and 1) than they are with the CTI configuration.

I think the Sony demodulator is just sensitive to CTI configurations. I bet if they switched to HTI, it would all work. They're not using all the cells in their frame as it is (they're leaving 51257 cells unused), so the "we're able to maintain the efficiencies of CTI" argument is weak.

Some additional info. I can't even test multiple PLPs with CTI on my open source ATSC 3.0 transmitter. When I implemented multiple PLPs with TDM and FDM, I didn't include the CTI interleaver in the frame mapper. There were no multiple PLP test configurations from ATSC with CTI (there are 22 ...