99 not 125, why?

Discussion in 'TiVo Coffee House - TiVo Discussion' started by rdrrepair, Apr 28, 2007.

  1. rdrrepair

    rdrrepair Bill Knapp

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    Today I gave my son his own TiVo. Not that big of a deal. He's had his own Tv in his bedroom for awhile now.

    Anyway, I hooked his TiVo set up using the RF cable in and out - no cable box.

    I hook his DVD/VCR player up using the RCA leads to the Tv set, input 1.

    I set the channel lock by allowing the Tv to redo channel search. After it locks into channel 3 I disconnect the cable feed in to the Tv - thus allowing it to only lock on channel 3 - I allow it to run up to channel 99 - thinking that it would be over I started to hook up the RF cable and it jumped to 100, 101, >>> 124, 125.

    I've always know that most Tv sets go up to 125 channels. I have just been so use to the cable only TiVo stopping at 99 channels. I just thought it was a little odd, like a 23 channel CB radio.

    So the question is...
    Why does my son's Tv set from 1990 go up to 125 cable ready channels and the TiVo from 2005 only go to 99 channels? Why not to 125? Why does the Tv not stop at 99?

    Not really that important - just curious. :confused:
     
  2. lessd

    lessd Well-Known Member

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    Ch 99 is below ch 8 on the frequency spectrum, its from the original way cable worked from the start because some of those frequencies were used by aircraft and at the start of cable the FCC was afraid that a cable leak might interfere with airplane communications. Ch 100 to 125 was almost never (if ever ) used by any cable co as they went to digital, so tuners above 99 make no sense. Its like UHF, the older tuners went to ch89 or something like that but no OTA station went that high so new tuners go only to a lower number, and the higher numbers went to other people for their non TV use. (I think Cell phones use some part of the old UHF band)
     
  3. CrispyCritter

    CrispyCritter Purple Ribbon Wearer

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    Lessd covered most things well. Cable companies have started to use above 99 more now, mostly for digital channels. The TiVo S3 goes to 125: it can handle the HD digital channels while the S2s can't.
     
  4. sfhub

    sfhub Well-Known Member

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    I would hope TiVo S3 can go to ch135 vs ch125, otherwise it won't be able to handle all the channels on 860MHz head-ends.
     
  5. CrashHD

    CrashHD I am the me.

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    UHF used to go up to 83. Now it goes somewhere in the high 60's. The frequencies from that uppper 60's cutoof point to channel 83 have been reassigned for mobile (cell phones and such) use, IIRC.
     
  6. CrispyCritter

    CrispyCritter Purple Ribbon Wearer

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    I'm not positive. I only saw it go up to 125 during the scan and afterwards, but I can't swear that it didn't quickly flash through 126-135 while I wasn't looking (assuming my local franchise doesn't do anything with 126-135). I certainly had no channels above 125.
     
  7. rdrrepair

    rdrrepair Bill Knapp

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    I don't understand your statement. The Tv set from 1990 doesn't handle HD either. :confused:
     
  8. lessd

    lessd Well-Known Member

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    Channel layout for cable

    Ch 2-6 is from 60Mhz to 88Mhz (all Freq are the Max for the channel)
    Cable 5A, ICC5, ICC6 is from 78Mhz to 90Mhz not used much, also known as A8-A6
    Cable 95-99 is from 96Mhz to 120Mhz Also known as Cable A-5 to A-1
    Cable 14-22 126Mhz to 174Mhz
    Cable 8-13 186Mhz to 216Mhz
    Cable 23-94 is from 222Mhz to 648Mhz
    Cable 100-125 is from 654Mhz to 804Mhz
    Cable 126- 135 is from 810Mhz to 864Mhz
    Cable 136 if there is any would start at 864Mhz and go up 6Mhz per channel

    All digital both HD and Non HD are in that frequency range, all digital channels have a dash or dot in them like 3-1 or 77-12. Ch 77 would be analog if it existed. With Cable cards the lineup gets re-mapped from ch 1 to 999 (all will not be used but could be) so in my Comcast cable co in CT 3-1 is CBS HD and the cable card re-mapped it to 233 and the frequency is 615Mhz or channel 89-x

    If the above is clear your better then most that why the cable co give out cable boxes or Cable Cards to make the numbers more understandable to people.
    I do not know if the Series 3 goes above 121 as that the highest Cable channel I have but I think it should cover the full range up to 900Mhz
     
  9. CrispyCritter

    CrispyCritter Purple Ribbon Wearer

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    I was just stating that there was no reason for an S1 or S2 to tune beyond 99, so they didn't, but there is a reason for the S3 to tune digital stations over 99 (though as I said in my area there was nothing beyond 125 that was detected.)
     
  10. sfhub

    sfhub Well-Known Member

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    This came up with the MyHD ATSC/QAM tuner card for PCs. That card has(had?) the limitation of 125. At the time most understood that 860MHz systems could go above 125, but until they started doing so, it wasn't that big a deal. A few weeks later, someone posted their cable system moved some digital channel above 125 and they weren't able to receive it. I think as cable companies look for more bandwidth for their HD channels to compete with DBS and FIOS, they will start using the higher channels and over time this could be an issue if TiVo can only go to 125.
     
  11. classicsat

    classicsat Astute User

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    My educated guess is the TiVo software as just written to 99, to make it easier to discern between no-box and box channels.
     

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