Whoah, Roamio Basic simultaneous OTA & cable.....sort of.

Discussion in 'TiVo Roamio DVRs' started by HarperVision, Oct 27, 2014.

  1. HarperVision

    HarperVision TiVo's Italian Cuz!

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    As I mentioned in another thread, I hooked up an antenna and redid guided setup. I left the cablecard and TA connected and only hooked up the antenna and disconnected the coax cable feed. When I got to the section right after it asked if I was setting up antenna or cable (I selected antenna of course), the next screen detected that I had a tuning adapter connected so it asked me if I wanted to setup for antenna AND cable or continue with only antenna setup. I was curios of course so I selected cable and antenna setup. It went through its usual paces and asked what cable provider I have, then downloaded what it usually does, then lo and behold it went to a follow on screen to scan and setup the antenna channels! I did that and once the scan was done it downloaded data again and voila', now both cable and antenna channels all show up in the guide, merged together! Of course only the antenna channels came in since that's what was hooked up, but the interesting part comes in when I swapped the coax cables back to the cable feed and now all of THOSE channels come in too.

    I'm thinking if someone really wants, they could use one of those old A/B RF coax switches with both OTA and cable. It could screw up some recordings of course, if the switch is in the wrong position when a recording starts on the other coax feed.

    I think I may have read something like this awhile ago when the Roamio was new and a lot of questions were being asked, but I don't think anyone ever got this far before, where they could feasibly have both at the same time, albeit using an RF switch. If so........never mind! :D
     
  2. worachj

    worachj Well-Known Member

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    Interesting! I wonder what would happen if you used a splitter in reverse and combined your OTA and cable signals and feed them to the TiVo.
     
  3. HarperVision

    HarperVision TiVo's Italian Cuz!

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    Yes, very interesting indeed and I'm surprised to wake up this morning to no replies to this very interesting nugget of information on the Roamio basic! People were clamoring and complaining when it first came out that it didn't do both, and now I found a way to do just that (sort of) and not a peep until you posted. :confused: I looked in the system information screen and it shows two input sources, antenna and digital cable, just like older version tivos. It acts like it has the 2 RF coax inputs, but of course it doesn't.

    I already tried what you're asking using a splitter, knowing with my background that it probably wouldn't work or at least reliably. The cable signal seemed to come in fine, but the antenna feed must've back fed all that cable co's coax and the signal strength dropped to an unusable level.
     
  4. bootman_head_fi

    bootman_head_fi Member

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    If the OTA QAM is the same freq as an incoming cable QAM, you would lose both.
    I would not recommend this since many OTA QAMs do overlap cable ones in the 500-750 MHz range..

    https://upload.wikimedia.org/wikipe...locations_Chart_2003_-_The_Radio_Spectrum.jpg
     
  5. worachj

    worachj Well-Known Member

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    Thanks for trying, I was hoping for the best knowing must likely it wouldn't work.
     
  6. HarperVision

    HarperVision TiVo's Italian Cuz!

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    OTA in the US and Canada doesn't use QAM, it uses ATSC 8-VSB. But yes, they would interfere regardless if they're on or even close to the same frequency.
     
  7. JimboG

    JimboG New Member

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    OTA HDTV doesn't use QAM, but cable does.

    If you multiplex the OTA signal and the cable signal, your OTA signal likely will land in the same frequency as a QAM, thus nuking both.

    On the other hand, an A/B switch wouldn't be a problem. It sounds like HarperVision may have found a way to mainly use cable, but add OTA channels that have better picture quality, or aren't included in your cable service, or are from a nearby out of market location.

    Examples of nearby local markets include Tucson in Phoenix, Flint and Toledo with Detroit, San Diego and Los Angeles, Baltimore and Washington, DC, etc.
     
  8. telemark

    telemark Active Member

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    That's cool.

    Might have better luck with a Band-pass combiner, or notch filter.
     
  9. HarperVision

    HarperVision TiVo's Italian Cuz!

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    I was thinking that, but I would think a few of the channels may actually share the same frequencies, so there would be no way to separate them. It would be very location specific I would think.
     
  10. cp2k

    cp2k Member

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    I've wondered the same thing, in our area Charter is all digital with all the HD channels in the 700's and 800's. I wonder if it would be possible to block all but the HD range and combine it with the OTA using this method?
     
  11. Bigg

    Bigg Cord Cutter

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    And you'd lose a bunch of cable channels, not knowing what you're going to lose until you lose them, and then if the cable company shuffles things around...

    Yeah, it's not going to work.
     
  12. snowman720

    snowman720 New Member

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    Dave,

    I have a Roamio Plus that is the cable ready model, not the OTA one. After reading your post it would appear that I could potentially 'cut the cord' from Comcast (keeping the cable card installed in the Tivo) and get the Tivo to work off an antenna. Would you agree?

    Thanks!

    Geoff
     
  13. kokishin

    kokishin Active Member

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    I'm not Dave... Dave was experimenting with a Roamio Basic which has tuners that can support either OTA or cable but not both together. That is why Dave had to use an A/B switch. The Roamio Plus and Pro tuners only support cable; not OTA.
     
  14. Bigg

    Bigg Cord Cutter

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    You have to give them back the CableCard when you terminate service, since they own it. Also, without their signal, the CableCard does jack ****. So that makes no sense.
     
  15. HarperVision

    HarperVision TiVo's Italian Cuz!

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    I wouldn't say it won't do "jack****e" since at least with my TWC they do have a lot of channels in clear QAM that aren't protected in both SD and HD, like TBS etc. so that's a channel that you wouldn't normally get OTA and could feasibly get without a Cablecard if you only subscribed to their basic service with Internet, which you'd probably keep even if you "cut the cord".

    As stated tho, you have to use the Roamio basic to do this.
     
  16. Bigg

    Bigg Cord Cutter

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    I totally missed that the post I was responding to was discussing a Roamio Plus, so it's even more nonsensical, since the Plus doesn't work with OTA in the first place.

    However, they wouldn't let you have a CableCard if you don't subscribe to the service, and Comcast doesn't have ClearQAM anymore. That being said, Limited Basic plus internet is about the same price as internet-only in most markets, and that will get you a CableCard and local channels, and would work with any Roamio model.
     
  17. HarperVision

    HarperVision TiVo's Italian Cuz!

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    I give up. You just keep missing the point. :rolleyes:
     
  18. telemark

    telemark Active Member

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    I didn't look up the numbers, but thinking aloud...

    Wouldn't this work with virtually all the hybrid Analog+Digital cable systems? That is Analog Cable would start at VHF channel 2 and go up from there, until it switches to digital cable at some point. ATSC should be all UHF & VHF depending on city with most of it UHF.

    So you just take the VHF+UHF frequencies from the Antenna and above that frequency from the Cable system, for digital cable / QAM.
     
  19. Bigg

    Bigg Cord Cutter

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    I understand you can tune a ClearQAM channel without a CableCard, if you have them in the first place. However, it is of no use beyond troubleshooting, as the TiVo doesn't know what it is.

    Very unlikely to work, and you'd need a whole bunch of notch filters. Most cable systems have stuff on pretty much every frequency except the FM band from 50mhz (upstream internet below that) to whatever they are capable of, anywhere from 550mhz to 1000mhz. And the systems that are still analog are, over time, converting to all digital.

    Also, even systems that haven't been converted to all-digital yet have had many channels removed so that they can be recycled for digital, so the band plan is an ugly mess. Comcast did that for several years, removing small batches of analog every so often and then adding more HD's a month or so later until they eventually nuked it completely and went all-digital. All cable systems with the exception of small private systems at hotels, universities, and hospitals are headed to all-digital, it's just a matter of how long the conversion takes.
     
  20. Dan203

    Dan203 Super Moderator Staff Member TCF Club

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    While this is cool, I wouldn't rely on it. Sounds like a software glitch that they will probably fix eventually. Also even if you could figure out how to combine the two signals via a notch filter there is no guarantee your cable company wouldn't move the channels. One of the features of CableCARD is that it contains a map between the channel numbers and the actual frequencies. Which means they could change the frequencies at any time and a normal user wouldn't even notice, but it could completely hose someone using a notch filter to block out specific frequencies.
     

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