So, after running an analog TV station on channel 19 UHF for a short stint, I now am aiming to run some DTV in the hi-VHF band. (Anything below that would need more power than I can afford to get the signal above noise). I figured some of you may be interested in what I have learned.
My experiments and findings have been interesting.
DTV is much more power-efficient than analog in my findings. Testing a digital signal on UHF 49, it kept a stable signal for much father distances than analog on the same frequency.
The highest-quality video I have been able to send over without artifacts or mux issues, is 1080i. 1080p can be done, but it looks horrific and is unwatchable thanks to the age-old MPEG-2 encoding that digital TV uses here in the US. I broadcast in 720p60 for several reasons -- progressive scan is far batter than interlaced for some source material, and it is less CPU intensive to encode oddly enough.
The most subchannels I have run are three: One an HDTV feed with Stereo sound, and two "radio" channels. Both 192 kbps audio streams. In practice, you can run as many subchannels as you like... assuming you want your video quality to suffer. I have found that 12< MBPS is great for 720p, and 2< is superb for 480p. 1080i holds fine at 16 MBPS, but again, interlaced video is very CPU intensive to record.
All of my TV setup used free/open-source software: gstreamer, Opencaster, GNURadio, and Snowmix. I will post details of the station setup later.
One thing I have yet to get working is the EPG (Program Guide/V-Chip). Otherwise, I have a virtual channel, (49), Station name, language, subchannels, etc. With an i7 or comparable CPU, you can get an incredible-looking 720p signal for your TX.
Here is a screenshot of my TV reciving a signal. Yeah, I like anime--sue me.
This is really awesome that you have figured all this out. There appears to be a lack of knowledge out there on how to setup pirate TV in general and now with it being digital over the air it becomes that much more off limits to those lacking the information.
It would be really neat if you could eventually setup a web page or some kind of documentation showing exactly how you did everything with links and information to help aid others who eventually wish to dabble in DTV pirating. I know there are even some hobby TV broadcasters using legal power levels that would be interested in this. Heck it could even be used for closed cable systems for campuses.
Maybe someone could even setup a few linux install packages like some debian and RPMs containing all the necessary software builds to make it that much easier for hobbyist to delve into this. I realize this is probably far more of an undertaking than you have time for but if you found enough others interested maybe it could happen.
There are so many people in my neighborhood dropping cable and sat. for OTA DTV. Even at our towns library they held a public how-to on making your own coat hanger 4 bay bowtie antenna. I wish that I went to that to help others but I didn't learn about it until after the fact Goes to show the interest is there from the publics perspective. Now get some hobbyist broadcasters on the TV and you have a whole new kind of pirate radio.
BTW I think DTV broadcasts use a lot less RF spectrum compared to the older analog format which would explain why you get farther broadcasting distance with it. The wider the bandwidth of a signal the more power it takes to get it out there.
I am beginning to consider opening a subforum for pirate TV if the interest grows around here.
Its really fun, documentation on PSIP has been a bit of a nightmare and nonexistent so it's been navigating old websites, reading poorly written manuals-- good times.
I do plan to write some guide here soon, I'll have to remember to post it here.
Now by possible, I mean technologically. Regulators will stifle it for 2 decades I'm sure.
Combine H.264/5 video with AAC+ or Opus audio, and you have a 16 MBPS 4K stream with transparent stereo sound. (being only 64 kbps for sound). You could still fit a 4:3 480i MPEG-2 channel in with it. Or... an extra 720p H.265 channel.
I managed to get ive 720p30 video from gstreamer > libav > ATSC transmitter. Only 77% CPU. It's a two-script setup, I may be able to get it down to one. A turnkey solution would be awesome.
Though, the PSIP muxer has a heart attack after about 15 minutes. Some phantom elementary streams creep in and make a mess. The signal then goes out sporadically as it's overloaded with junk data.
Once that is done, all I need to do is comment the code, write a little instruction book, and then put it on my Sourceforge and github.
I managed to get ive 720p30 video from gstreamer > libav > ATSC transmitter. Only 77% CPU. It's a two-script setup, I may be able to get it down to one. A turnkey solution would be awesome.
Though, the PSIP muxer has a heart attack after about 15 minutes. Some phantom elementary streams creep in and make a mess. The signal then goes out sporadically as it's overloaded with junk data.
Once that is done, all I need to do is comment the code, write a little instruction book, and then put it on my Sourceforge and github.
Just an update. Got the encoding moved to one script. Still trying to be the Electronic Program Guide fully implemented. One last snag I have some emails out about. . Once that's squashed, I'll get a guide up on my server.
you may want to look at this guy wa6rzw.homelinux.net/addon/adtv/ he is doing digital TV on the ham bands. i actually went to meet and see this guy. he has a pretty high quality impressive and professional DTV setup. while he is ham and not pirate it is still impressive all the same.
JD
"The scientists of today think deeply instead of clearly. One must be sane to think clearly, but one can think deeply and be quite insane."
Flush Rush, Pull your head out of Fox Boobs, tune in more C-Span, Norman Goldman, and Thom Hartmann, you might just surprise yourself and learn something!!!
Hi, this is Joe in Texas. I'm the guy who last year put a couple of analog (still licensed, but abandoned by the licensee) LPTV stations back on the air in Houston Texas. See www.kvdo.net The licenses expire on 8.1.14 and the FCC sent me a letter dated 5.2.14 giving the licensee (not me) 30 days to file a renewal or the license would be permanently suspended. I pulled the plug on the stations last week and went to Washington to see a senator and the FCC, trying to convince them to do an involuntary license transfer and let me renew the licenses. They agreed to file the paperwork, but their decision is still out.
Why don't you just get a simple HD digital modulator with an HDMI input? Like one of these... www.provideoinstruments.com/pvi-hd-rf-modulators.html You can feed the video directly from a DVD player or computer. Run the RF output from the modulator to the same driver amp and power amp used for analog TV. Very easy to do and it works!
Hi, this is Joe in Texas. I'm the guy who last year put a couple of analog (still licensed, but abandoned by the licensee) LPTV stations back on the air in Houston Texas. See www.kvdo.net The licenses expire on 8.1.14 and the FCC sent me a letter dated 5.2.14 giving the licensee (not me) 30 days to file a renewal or the license would be permanently suspended. I pulled the plug on the stations last week and went to Washington to see a senator and the FCC, trying to convince them to do an involuntary license transfer and let me renew the licenses. They agreed to file the paperwork, but their decision is still out.
Why don't you just get a simple HD digital modulator with an HDMI input? Like one of these... www.provideoinstruments.com/pvi-hd-rf-modulators.html You can feed the video directly from a DVD player or computer. Run the RF output from the modulator to the same driver amp and power amp used for analog TV. Very easy to do and it works!
TVJoe.net It's like radio, but with pictures!
...because I still would have to manage PSIP data on my PC, and I like using open source software. Thanks for the link though. Also, i work minimum wage so...that is well out of my budget.
you may want to look at this guy wa6rzw.homelinux.net/addon/adtv/ he is doing digital TV on the ham bands. i actually went to meet and see this guy. he has a pretty high quality impressive and professional DTV setup. while he is ham and not pirate it is still impressive all the same.
Looks like he's using DVB-S, which is common on the ham bands. I want to be able to decode video/audio on my consumer television. I already have a fully working transmission chain, so I don't see much use in switching to a standard nobody can watch.
I am beginning to consider opening a subforum for pirate TV if the interest grows around here.
Please do Sir - I'm still here - got divereted with "life" , but still planning to broadcast analog lowpower TV. as you may know I have most of what I need. just need to build a PC, antenna and collect programing.
don't forget me!!!!!!!!!!!!!!!!! - I'll deliver eventually! - just got a couple of things I need to take care of first ;-/.
damn life.
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I'd welcome a LPTV section to your forum myself ;-).
I am beginning to consider opening a subforum for pirate TV if the interest grows around here.
Please do Sir - I'm still here - got divereted with "life" , but still planning to broadcast analog lowpower TV. as you may know I have most of what I need. just need to build a PC, antenna and collect programing.
don't forget me!!!!!!!!!!!!!!!!! - I'll deliver eventually! - just got a couple of things I need to take care of first ;-/.
damn life.
----------------
I'd welcome a LPTV section to your forum myself ;-).
peace.
It would be nice to have one, yeah. I have AM Stereo and FM/RDS projects going too, but an LPTV forum could foster interest..and with the reasearch I've done and the tools that are now available, it would be cool to see.
Speaking of which, I am almost done writing some documentation on DIY digital TV. Using entirely free software, (gstreamer, and Opencaster). I've managed to figure out MOST of how PSIP works...the documentation out there is horrible, and there isn't much in the way of userland support. Needless to say, it has been interesting.
My current workflow uses gstreamer-0.10 for MPEG-2 video encoding, and Opencaster to insert PSIP packets. This is all done on one computer; and with me getting a Decklink Recorder soon, I will be able to use a much smaller computer to do the encoding and muxing. With this, you wouldn't even need an SDR, so long as your ATSC transmitter takes direct TS input over a network, USB, etc; it should work great.
The above outputs a 10 MB/s 720p60 video feed...now, the reason it's 10 MB/s, is due to the encoder having a limit. I still need to patch it. :l With the above code, you get something that not only checks out in TSReader, but also plays great on your TV:
So, the million dollar question is what the heck do you use for your ATSC transmitter/modulator? I don't see you specifically mention it anywhere? A bladeRF or some other type of SDR?
BladeRF. Any device compatible with GNURadio will suffice. A USB2 and USB3 code for the transmitter are available. So a USRP, HackRF, BladeRF, all should work 100%. The real burdensome task, is the encoding. I currently have a setup with 1080p24 video and 224 KB/s stereo sound over ATSC.
Looks great, but my computer isn't a fan. Gtsteamer and FFMPG/libav seem to work about the same when it comes to handling MPEG-2.
Interesting. I prefer to homebrew all my own equipment, if possible. Or, at the very least, put together a kit. But, I guess modulating over one or two varicaps just isn't going to cut it as far as ATSC is concerned, and at 700MHz, my techniques would fail.
Amazing, really, since just a few years ago nothing like this was available with anything approaching a consumer-friendly price. $400-600 plus PC is still a bit steep, but a lot better than the 4 and 5 digit offerings of the past. Add an amp and filter and you're in business. Guess I need to start learning a circuit layout program. Are distributed elements used at this freq? Hmm...
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