Link ATV video signal to other repeaters?

Discussion in 'Echolink/IRLP Tech Board' started by K3RW, Apr 17, 2017.

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  1. K3RW

    K3RW Ham Member QRZ Page

    I found that in Echolink I can link an amateur television repeater with another, but I've only seen people do this with audio. IRLP, from what I can tell, same thing.

    Is there a way to link the audio AND the video to other repeaters? Maybe its not in Echolink or IRLP, but I'm wondering if there is a way to have a repeater here link to a repeater elsewhere, so we can do 440 ATV over it. I'd be happy with a lower bitrate, etc., if we could just link the repeater here to another one.

    The Portland area geography is challenging for people to hit the ATV repeater, mainly due to LOS issues. And it would get a lot more use if it were linked to other repeaters. I've not seen another ATV repeater do an internet link this way, but I'm guessing it is somehow possible.
     
  2. KA9JLM

    KA9JLM Ham Member QRZ Page

    You could do it using VLC.

    [​IMG]
     
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  3. K3RW

    K3RW Ham Member QRZ Page

    Neato! Looks like I will need the repeater to have some interface on it.

    Goal would be to have people use the repeater but not have to have actual LOS of it--but rather another repeater. So those would be linked.

    I suppose a different method would be to have it be even more like Echolink, whereas one operator might be able to tie into it with no ATV stuff. If we could do either of these, particularly the second one, I think it would be fantastic. Dreaming big perhaps!
     
  4. KA9JLM

    KA9JLM Ham Member QRZ Page

    That would be no problem, But some type of computer would be required.
     
  5. K3RW

    K3RW Ham Member QRZ Page

    I was thinking something like a Raspberry Pi 3. Probably need some special plug in card and a bunch of GPIO jumpers, and some software to handle it.

    IRLP DATV seems to be closer to what I'm describing but I'm not familiar enough with the nuances to know if this is totally different.
     
  6. KB0MNM

    KB0MNM Ham Member QRZ Page

    If you want real-time video, you may need to check out High Speed Multi-Media ( HSMM ) using regular older WiFi equipment and appropriate amplifiers and antennas. There is one major analog ATV vendor left: PC Electronics. You may find yourself better informed if you can get a few copies of ATV magazine- I used to get mine through Satellite City in Mound, Minnesota ( see combined Lentini ad in older QRZ magazines ).
     
  7. K3RW

    K3RW Ham Member QRZ Page

    Chatting with some folks overseas I get the impression that I must use digital ATV to do this type of interactivity. Problem is that almost no one stateside has DATV equipment. In our favor, BATC already streams online our repeater. So I just need the tx component. Perhaps these might work:
    • Have a hardware/software solution to allow streaming in and out of a microcomputer, which interfaces with the repeater controller. Whether its 1, 2 or more hardware chunks, the internet stream is digital and the repeater isn't. So to interact with it, at some point it has to be converted to analog so it can output on 1255. So the microcomputer needs to be able to handle an internet stream, convert the signals from digital to analog to interact with the repeater controller. And it needs some component like push-to-talk or it will send the stream continuously.
    • OR, have a dedicated 'slave' ATV transmitter, which has a microcomputer connected to it allowing the streaming audio/video in, and converts it to analog and outputs it through the audio and mic jacks on the slave transmitter. Its basically substituting the audio/video component with an internet stream instead of the traditional camera/mic or camera + mic.
    The second solution might be easier than the first one, if either is possible. Three is the way to get around all these software and hardware conversions. Maybe the first one would work like this:


    upload_2017-4-20_5-40-12.png

    And in this way, on the top line the repeater works as it normally does with a cross-band 426/1255 setup. Radio keys the repeater with analog, it outputs on 1255. Anyone with a downconverter or rx capability can see the analog signal.

    But the added component is the signal from the PC can interface with the repeater controller too.

    #2 solution would be simpler--if I can figure out how it might work:

    upload_2017-4-20_5-24-34.png
     

    Attached Files:

  8. KB0MNM

    KB0MNM Ham Member QRZ Page

    Older PCs already have Digital to analog converters built into their display cards: The IBM XT standard CGA 'color' card puts out composite video, as do many of the 'clone' PC cards which can support higher resolution ( and the CGA standard composite ). There are many VGA to composite converters which simply combine the separate Red, Green, and Blue analog signals from a de-9 connector ( for VGA ) to an RCA connector for connection to a CGA or better composite display. The displays capable of multiple synchronization rates ( eg. 'Multisync' ) were relatively expensive until VGA and XGA converters at approximately $100.00 to $200.00 each flooded the market. Many of these adapters also required an extra serial port for control. Just be aware that the old NTSC standard video had a slightly different rate from most CGA and VGA cards, and that was the reason for the external adapters. Black Box(mfr.) has supplied many different adapters of this sort for years, yet they are seldom known as the least expensive. They do carry a no-nonsense warranty, however, which can make up for a price difference. 73
     
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  9. K6ABZ

    K6ABZ Ham Member QRZ Page

    First question, which makes all the difference: do the computers you want to link have Internet connections, and do they have enough bandwidth to support TV?

    The simplest and most flexible way to do this would be a VGA or HDMI to TV adapter on a computer, paired with a composite capture device (something like a WinTV.) Set up something like TeamViewer, and you can basically remote-control the PC via the Internet and use the ATV transmitter and receiver on the repeater as a webcam and monitor.

    This has an added bonus in that the remote station doesn't even need to be an ATV station. You could link someone via Skype or Hangouts directly. Obviously, you'll need a way to lock out users or only allow ham operators - but that should be a matter of authorizing specific accounts to log in to the system.
     
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  10. KB0MNM

    KB0MNM Ham Member QRZ Page

    So to summarize, you could do something like this: 1. Take the composite 1VPP NTSC video feed that would go to an existing 70cm ATV transmitter and split it into two feeds ( one for the pre-existing and one for a capture device ). 2. Use the new composite video capture device ( such as the WinTV accessory for a PC ) and an Ethernet(tm) connection from that same PC to feed a remote communications device pair. This pair could be a D-Star 1.2 Ghz. data link, modem-to-modem ( ADSL-type? ) link, or other means of getting the captured video and audio to the remote site. 3. Recover the video and audio with a PC that includes the same Ethernet(tm) and a display device capable of producing composite video or a format which can be converted to composite, as well as the audio ( might require a separate device ). 4. Feed same composite signal & audio to the new 'cloned' ATV transmitter. Why Ethernet(tm), you ask? Because it facilitates high-speed linking, including HSMM aka beefed-up WiFi routers that can be set-up legally with an amateur radio license and the appropriate safeguards, eg. authorized user accounts. 73 P.S. Ref. bio of Don Metcalfe, pioneer of early Ethernet(tm) communications and the DIX/AUI 15-pin ( now considered antique ) / coax ( sometimes still used in Thin-net rather than Thick ) and RJ-45 interfaces.
     
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