ATSC 3.0: Washington, DC / Baltimore, MD

ATSC 3.0 Forum
joblo
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ATSC 3.0: Washington, DC / Baltimore, MD

Post by joblo »

After a delay to resolve issues with the FCC, Sinclair is now approved to begin 3.0 broadcasts tomorrow in Washington, DC:

https://wjla.com/news/local/do-you-watc ... march-25th

The Baltimore rollout is now in its second delay pending FCC approval of a somewhat unusual simulcast plan, but scheduled to begin June 8th:

http://cwbaltimore.com/station/rescan-day

https://enterpriseefiling.fcc.gov/datae ... b&goBack=N

The following 4K band scanners receive 1.0 service from these two transmitters and should receive at least some 3.0 service at least some of the time:

https://m.rabbitears.info/index.php?req ... it=&auto=Y
https://m.rabbitears.info/index.php?req ... it=&auto=Y
https://m.rabbitears.info/index.php?req ... it=&auto=Y

I know at least the first two above are 4K-DEVs, and there is at least one other 4K owner posting in the AVS Washington-Baltimore thread:

https://www.avsforum.com/threads/washin ... t-60533330

More after 3.0 goes live... "watch this space".

Trip
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Re: ATSC 3.0: Washington, DC / Baltimore, MD

Post by Trip »

Now seeing it here in Alexandria. Just the one channel in (I assume) 1080i. Bitrate about 8 Mbps.

trip@trip-G752VY:~$ hdhomerun_config 10805D4A get /tuner0/plpinfo
0: sfi=0 mod=qam16 cod=9/15 layer=core ti=cti lls=1 lock=1

- Trip

Trip
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Re: ATSC 3.0: Washington, DC / Baltimore, MD

Post by Trip »

By digging into the manifest.xml file, I think I have determined that the video is actually 1080p.

<Representation bandwidth="7500000" codecs="hvc1.2.4.L123.11" frameRate="60000/1001" height="1080" id="Video1_1" sar="1:1" scanType="Progressive" width="1920">

A user on AVS reports the Stirr app is present on WIAV-CD, but I don't see any evidence of this in my dash-tar dump. How should I go about trying to find its files in the data stream, if it's actually there?

And nickk, how about making access to the manifest.xml file a part of the standard firmware somehow? Assuming the parameters are pretty straight-forward, that would be a good way to get data onto RabbitEars about what the stations are up to on 3.0.

- Trip

stvcmty
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Re: ATSC 3.0: Washington, DC / Baltimore, MD

Post by stvcmty »

What is the required dBm or field strength for a HDHR Connect 4k to get a lock on WIAV? Rabbitears search says I have -94 dBm (36 dBuV/m) at the height/location of my antenna. My Connect 4k says there is a quality of 15% to 21% with a strength of 52% to 56%; it says the Modulation Lock is atsc3. I can optimize my system some but if there is a cliff and I am not going to get over it I don’t want waste my time/money/energy. I am using a HD8800; if I go to a better 8 bay I might gain a dB or two. I am using an RCA preamp, if I get one from kitztech I might get rid a dB of noise. I can put my antenna up 12’ higher but Rabbitears predicts a bit of loss if I do that. I have a UHF bandpass filter from jan_jenca before my preamp that causes 1.5dB of insertion loss but that is to keep LTE/5G out of the preamp. The limit might be putting the Connect 4 in a weather proof enclosure right behind the antenna, no preamp or anything. I am 52 miles from the tower so I did not expect it to work but when the Connect 4k was able to say it is ATSC 3.0 and give me a quality number I was surprised. I know WNUV will be ATSC 3.0 in a few months and I may just have to wait.

jonw747
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Re: ATSC 3.0: Washington, DC / Baltimore, MD

Post by jonw747 »

I'm seeing video from WIAV, and it's HEVC, but I'm not getting audio. Is that to be expected? Or is it because I'm missing a codec?

(goes and reads sticky)

Ok, I guess it's a codec issue. Finally time to start catching up with how to make this ATSC 3 stuff work.

twobucktoll
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Re: ATSC 3.0: Washington, DC / Baltimore, MD

Post by twobucktoll »

On the cutover date (3/25/2021) I was trying to keep an eye on WIAV while also trying to get some work done. Sometime between 11 am and 11:30 I noticed the old signal was gone. After rescanning I saw WIAV had moved its virtual channel from 58 to 158 and was still showing TBD network as it was before, but with atsc3 modulation. VLC reported it as 1920x1080 30 FPS but I can’t tell if it is interlaced. And I ran into the problem with no audio through VLC. Audio is fine on the HD Homerun and Channels apps on my iPad and phone, and also the HDHR Amazon Fire Stick app. I cannot get Plex to recognize the channel much less play or record it.

The content seems to be mostly the TBD network, but there is a time on weeknights where the WJLA local news is rebroadcast. I have seen it around 7 or 7:30 pm. The studio shots in the newscast look very very good on my TV through the Fire stick using the HDHR app. They look much better than the simulcast on 10.1. There are deeper colors and sharper lines. You can tell the anchors are wearing makeup.

jasonl
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Re: ATSC 3.0: Washington, DC / Baltimore, MD

Post by jasonl »

stvcmty wrote: Fri Mar 26, 2021 12:26 pm What is the required dBm or field strength for a HDHR Connect 4k to get a lock on WIAV? Rabbitears search says I have -94 dBm (36 dBuV/m) at the height/location of my antenna. My Connect 4k says there is a quality of 15% to 21% with a strength of 52% to 56%; it says the Modulation Lock is atsc3. I can optimize my system some but if there is a cliff and I am not going to get over it I don’t want waste my time/money/energy. I am using a HD8800; if I go to a better 8 bay I might gain a dB or two. I am using an RCA preamp, if I get one from kitztech I might get rid a dB of noise. I can put my antenna up 12’ higher but Rabbitears predicts a bit of loss if I do that. I have a UHF bandpass filter from jan_jenca before my preamp that causes 1.5dB of insertion loss but that is to keep LTE/5G out of the preamp. The limit might be putting the Connect 4 in a weather proof enclosure right behind the antenna, no preamp or anything. I am 52 miles from the tower so I did not expect it to work but when the Connect 4k was able to say it is ATSC 3.0 and give me a quality number I was surprised. I know WNUV will be ATSC 3.0 in a few months and I may just have to wait.
You're not going to find an antenna that's better enough than the HD-8800 to matter, at least not without building your own from the right set of plans or importing one from the UK. Most commercially-available 8 bay bowties in the US are worse than the HD-8800 on the current UHF band.

xmguy
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Re: ATSC 3.0: Washington, DC / Baltimore, MD

Post by xmguy »

twobucktoll wrote: Sat Mar 27, 2021 9:03 am On the cutover date (3/25/2021) I was trying to keep an eye on WIAV while also trying to get some work done. Sometime between 11 am and 11:30 I noticed the old signal was gone. After rescanning I saw WIAV had moved its virtual channel from 58 to 158 and was still showing TBD network as it was before, but with atsc3 modulation. VLC reported it as 1920x1080 30 FPS but I can’t tell if it is interlaced. And I ran into the problem with no audio through VLC. Audio is fine on the HD Homerun and Channels apps on my iPad and phone, and also the HDHR Amazon Fire Stick app. I cannot get Plex to recognize the channel much less play or record it.

The content seems to be mostly the TBD network, but there is a time on weeknights where the WJLA local news is rebroadcast. I have seen it around 7 or 7:30 pm. The studio shots in the newscast look very very good on my TV through the Fire stick using the HDHR app. They look much better than the simulcast on 10.1. There are deeper colors and sharper lines. You can tell the anchors are wearing makeup.
That's what Nashville Sinclair has done too with it's CW RF 30 3.0 channel. The QAM16 is TBD also. Not sure why they're pushing this one so much. They've put their other lighthouse stations on PLP1/QAM256/COD11/15.

kyl416
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Re: ATSC 3.0: Washington, DC / Baltimore, MD

Post by kyl416 »

twobucktoll wrote: Sat Mar 27, 2021 9:03 ambut there is a time on weeknights where the WJLA local news is rebroadcast
That's because WIAV-CD is a Class A license, so they have additional local programming/public affairs requirements, which they meet by airing a rebroadcast of the news from their sister station WJLA.

stvcmty
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Re: ATSC 3.0: Washington, DC / Baltimore, MD

Post by stvcmty »

stvcmty wrote: Fri Mar 26, 2021 12:26 pm ...I am 52 miles from the [WIAV] tower so I did not expect it to work but when the Connect 4k was able to say it is ATSC 3.0 and give me a quality number I was surprised. ...
I was able to watch the ATSC 3.0 signal. I used Signal GH on my phone to help me fine-tune the aim of my antenna (being on a tower next to WRC helped aim it) then I watched for a lock.
Virtual Channel 158.1 WIAV
Frequency 569.000 MHz
Program Number 5001
Modulation Lock atsc3
Signal Strength 55%
Signal Quality 49%
Symbol Quality 100%

Is ATSC 3.0 more tolerant of a strong adjacent channel? WIAV is next to WETA and at my site the signal strength predictions are 20dB different.

jasonl
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Re: ATSC 3.0: Washington, DC / Baltimore, MD

Post by jasonl »

Signal strength difference between adjacent channels isn't really an issue with modern digital tuners because of the fundamental difference in how digital tuners work compared to analog tuners (note that this has nothing to do with digital vs. analog broadcasts). Silicondust moved the HDHomeRun to digital tuners in gen 3, which was in 2011 or thereabouts. ATSC vs. ATSC3 is not significant for that. The modulation settings used by ATSC 3 and the SNR requirements implied by them make a far bigger difference.

Trip
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Re: ATSC 3.0: Washington, DC / Baltimore, MD

Post by Trip »

WIAV-CD just changed its modcod to QPSK and 7/15 FEC, so the minimum SNR is now around 4 Mbps. They've cut the bitrate on their video down to the 3-3.5 Mbps range.

I wish plpinfo (or a more detailed version of it) could spit out some of the other parameters, like the LDPC, FFT, Guard Interval, etc.

- Trip

joblo
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Re: ATSC 3.0: Washington, DC / Baltimore, MD

Post by joblo »

Well, that didn't last long... still 7/15, but reports qam16 when I checked just now...

Hey Sinclair, leave a config change like that up for at least 24 friggin' hours, could ya please, so those of interested could have a chance to notice and play with it a bit, y'know?

Thanks so much...

joblo
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Re: ATSC 3.0: Washington, DC / Baltimore, MD

Post by joblo »

Ok, back to qpsk 7/15... able to lock PLP0 at 2 dB SNR, -99 dBm...

VLC picture is crap at any level, though, even 16dB/100%...

3-3.5 Mbps apparently not enough bandwidth...

xmguy
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Re: ATSC 3.0: Washington, DC / Baltimore, MD

Post by xmguy »

joblo wrote: Thu Apr 01, 2021 5:36 pm Ok, back to qpsk 7/15... able to lock PLP0 at 2 dB SNR, -99 dBm...

VLC picture is crap at any level, though, even 16dB/100%...

3-3.5 Mbps apparently not enough bandwidth...
Wow. That's strange. My Nashville area is staying (As far as I know) with QAM 16/256. I wish they'd try QAM64 or PSK encoding. Sounds like the engineer at your Sinclair station doesn't know which to stay at. I assume they'll go with QAM like most of the others. QAM16 at 3.3 Mbps is enough to decode a 720P image crystal clear in VLC. I get micro blocking alot at QAM256 since I have issues getting a lock.

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