1. This site uses cookies. By continuing to use this site, you are agreeing to our use of cookies. Learn More.

** HD TiVo and HD DirecTV TiVo FAQ **

Discussion in 'DirecTV TiVo Powered PVRs & Receivers' started by feldon23, Jan 1, 2004.

  1. Apr 1, 2004 #581 of 1440
    AbMagFab

    AbMagFab What happened, TiVo?

    3,638
    0
    Feb 5, 2001
    Any signal combination like that will result in a ton of interference, and an almost unusable end result. You need to filter each half before merging them.

    For example, you could filter all UHF from the VHF cable, and all VHF from the UHF cable, and then try that. Or even better get a modulator, take the VHF channel you want, and modulate it to a specific spot on the UHF cable (rather than merging the entire feed from both).
     
  2. Apr 1, 2004 #582 of 1440
    Tom in OH

    Tom in OH New Member

    335
    0
    Mar 12, 2004
    Shelby, OH
    I've never tried combining the UHF and VHF signals from 2 different antennas but u might be right about the interference. How then do VHF/UHF/FM antennas deal with this issue?

    Thx, Tom
     
  3. Apr 1, 2004 #583 of 1440
    Darin

    Darin Way Left

    1,995
    0
    Dec 26, 2001
    Atlanta, GA...
    If it's all coming from a single antenna, its' not an issue because there's only one source. It's not that VHF interferes with UHF, it's that there are two sources that could be picking up the same signal, and if they're out of phase in the slightest they interfere with each other. But you can easily and cheaply combine separate UHF and VHF antennas with a joiner meant specifically for that purpose, such as the 0549 shown at the bottom of this page. I'm doing that now with a separate VHF and UHF antenna on my roof, and I also have one of the jointennas to merge in a signal from a third antenna for a single station in the opposite direction.
     
  4. Apr 1, 2004 #584 of 1440
    Tom in OH

    Tom in OH New Member

    335
    0
    Mar 12, 2004
    Shelby, OH
    Thx Darin for the input. I might need that webpage in the future. Your roof must look very kewl(if u ask me) but also u must have a Very easy going wife. Mine has complained ever since she saw the size of the ota I brought home and it's not even on the roof yet....
     
  5. Apr 1, 2004 #585 of 1440
    AbMagFab

    AbMagFab What happened, TiVo?

    3,638
    0
    Feb 5, 2001
    Yup, that'll do the trick. Those Jointenna's are performing the filtering before merging, so you don't get the cross interference. I like the ones on the top of the page that do it for a specific channel, much better than modulating out through some other device.
     
  6. Apr 1, 2004 #586 of 1440
    Darin

    Darin Way Left

    1,995
    0
    Dec 26, 2001
    Atlanta, GA...

    Heh, well, it does look kinda funny. I've got a mast in the middle at the very peak with the UHF and VHF antenna on it (the third OTA is in the attic), a Dish500 at one corner for 110 & 119, and a 30" at the opposite for 101. I've thought about putting flashing lights on them for kitch factor, but that's another project I'd never finish.
    You still have much to learn. :D ;)
     
  7. Apr 1, 2004 #587 of 1440
    edrock200

    edrock200 New Member

    2,569
    0
    Feb 7, 2002
    Northern...
    LOL! :D
     
  8. Apr 1, 2004 #588 of 1440
    Toeside

    Toeside Circa Dec 2005

    3,386
    0
    Feb 14, 2002
    St Louis, MO
    He must me a newbie. :p I was wondering how you'd reply to that statement.
     
  9. Apr 1, 2004 #589 of 1440
    Bigg

    Bigg Active Member

    5,427
    5
    Oct 30, 2003
    Hartford-...
    Nice sounding anetnna setup. thx for the info on UHF and VHF combing. The UHF and VHF antenna combiner will be useful when I get HD, with NBC and CBS on UHF aways away, and ABC on VHF practically right next door (I get their analog with a coathangar).
     
  10. Apr 2, 2004 #590 of 1440
    DavidTigerFan

    DavidTigerFan No, not Detroit. TCF Club

    11,951
    47
    Aug 18, 2001
    Charleston, SC
    Hey guys, need a little help. I got a new Phase III dish. I want to run Feldon's first scenario where I have 2 outputs of the dish go into a 2x4 multiswitch and 2 going to the HDtivo when I get it. (in the mean time I will have an HD receiver plugged in). However the Phase III dish has no labels for the outputs. How do I know which ones point to what satellites?

    -DTF
     
  11. Apr 2, 2004 #591 of 1440
    dswallow

    dswallow Save the ModeratŠ¾r TCF Club

    50,975
    31
    Dec 3, 2000
    Long...
    It doesn't matter. The Phase III dish has a built-in multiswitch. The 2x4 multiswitch you have will send 13v to whatever is connected to one input and 17v to whatever is connected to the other input. The voltage will tell the built-in multiswitch what signal to pass through to it. All will work as designed. ;)
     
  12. Apr 3, 2004 #592 of 1440
    DavidTigerFan

    DavidTigerFan No, not Detroit. TCF Club

    11,951
    47
    Aug 18, 2001
    Charleston, SC
  13. Apr 6, 2004 #593 of 1440
    Special_Ed21

    Special_Ed21 TiVo Geek

    57
    0
    Mar 27, 2004
    Las Vegas, NV
    I have the Samsung HLN617w DLP and have pre-ordered the HR10-250 HD. It looks like I will be switching resolutions often using the up arrow on the remote or the front panel switch. Unfortunately my mother is very tech challenged and will be very confused as to which resolution to use and will probably just watch whatever setting it happens to be on.

    I want to know if the SD signals will look better with the DVI output than my current Hughes HDVR2 S-video output. Any thoughts on this?
    :(
     
  14. Apr 6, 2004 #594 of 1440
    matL

    matL New Member

    14
    0
    Apr 6, 2004
    from the FAQ, I see cables are included :) All this waiting is getting to me & I was thinking I could go buy something - to be 'ready'.



    Anyone have details on the supplied cable size/ quality (subjective) that come with?
    Thanks

    *edit* found the types withing this post - still wondering if anyone has LENGTH and 'quality'?
     
  15. Apr 6, 2004 #595 of 1440
    Tom in OH

    Tom in OH New Member

    335
    0
    Mar 12, 2004
    Shelby, OH
    The HDMI-->DVI cable will strip the audio but will keep the video signal in all its digital glory. I've heard the DVI output refered to as a "bit bucket" which means it sends a uncompressed digital signal to your display device. It certainly would be well worth a try using the DVI input on your DLP opposed to the s-video for SD channels. My bet is they'll look much better.
     
  16. Apr 6, 2004 #596 of 1440
    k2ue

    k2ue Retired RF Engineer

    653
    0
    May 9, 2002
    Victor, NY
    I currently let my Samsung TS360 HD receiver scale my HDVR2 to 720p (from S-video) to drive my HLN467W. While the black level is incorrectly elevated on the HDVR2 compared to the TS360's own video, there appears to be no other issues, and the HD TiVo would not have the Black problem. I would also note that while my TS360 supports Native output I stopped using it because the HLN blanking and flashing when clicking thru stations (as it tried to scale each differently) was very annoying. Sharpness on the HLN seems to be a significant factor on SD -- I've settled on 30, since it seems to to affect HD much no matter where it's set.

    So I'm planning to just let the HD TiVo output 720p, except when watching in the bedroom via a modulator.
     
  17. Apr 8, 2004 #597 of 1440
    bkdtv

    bkdtv New Member

    7,902
    0
    Jan 9, 2003
    DC Metro Area
    Re-posted from another thread...

    We know that the current DirecTivo uses the Broadcom BCM702x chip for its graphics and PVR functionality. This chip supports HD, when supplied with the appropriate memory and output circuitry (which obviously the Series2 does not have). Dish Network uses the BCM702x in their Dish 921 PVR.

    From this press release back in January, we know that the HDTV DirecTivo uses a newer-generation BCM7037 chip. Unfortunately, Broadcom doesn't provide documentation on the BCM7037.

    Broadcom does provide information on the BCM7035 and BCM7038. The BCM7035 offers comparable functionality to the BCM7020 used in the current Series2 Tivo, but with a dedicated 3D engine. The BCM7038 offers a number of key improvements over the BCM7035, including 3/2 pull-down with automatic scene detection, built-in DVI-HDMI transmitter, an Ethernet MAC/PHY, dual USB 2.0 and dual SATA controllers, and a 3D comb filter for SD analog outputs.

    It's not clear what features the BCM7037--used in the HDTV DirecTivo--is missing from the BCM7038. What is obvious: the BCM7037 in the HDTV DirecTivo is a significant step-up from the BCM702x used in the SD DirecTivo and the Dish 921 HD PVR.

    Another interesting bit...

    The BCM7038 product brief mentions a BCM3520 VSB/QAM demod. There is no other mention of the BCM3520 on Broadcom's web site.

    The 2+year old BCM3510 is the VSB/QAM demod used in the Dish 921HD PVR. It delivers acceptable off-air reception for local signals, but doesn't equal the reception performance of the newest DirecTV HD STBs. It is at least possible that the HDTV DirecTivo uses the unannounced BCM3520 part, but it's not clear what improvements this will offer.
     
  18. Apr 9, 2004 #598 of 1440
    Hootydog

    Hootydog New Member

    44
    0
    Jan 19, 2004
    East Bay...
    Same set up here with great results from 30 miles away from Sutro tower behind the East Bay hills.
    Chappy
     
  19. Apr 9, 2004 #599 of 1440
    midas

    midas I heard that

    12,322
    5
    Jun 1, 2000
    Montgomery,...
    What's the difference between a regular amp and a pre-amp?
     
  20. Apr 9, 2004 #600 of 1440
    dswallow

    dswallow Save the ModeratŠ¾r TCF Club

    50,975
    31
    Dec 3, 2000
    Long...
    I can kind of answer that. ;)

    Read this: http://www.hdtvprimer.com/ANTENNAS/basics.html

    A weak signal traveling through a length of coax loses some of its power for every foot it travels (about 1db per 18 feet or so, depending on the cable); that is the noise floor and the signal peaks become closer together. When you get to your receiver there can be little difference between the two, and the receiver is unable to do anything with it.

    For that reason, you want to amplify the signal as close to the source as you can and use a pre-amplifier that adds as little noise to the signal as possible. The job of the pre-amp is to boost the signal to offset loss down the transmission line.

    The most important factor is the signal-to-noise ratio; you need a certain ratio or higher for a receiver to be able to do anything with the signal. So by amplifying as close to the antenna as you can, you have the best chance of actually improving the ratio so that it can survive any loss through the rest of the transmission system.

    An amplifier (or really, a distribution amplifier) is designed to boost the signal sufficiently along the transmission path to deal with loss through splitters or longer runs of cable.

    Is there any real difference beyond the usual differences in design between models and manufacturers? I don't think so -- of course those differences between models and manufacturers are important. But amplifying a signal at the receiver is practically useless since there's nothing it can do the receiver couldn't do itself; there's no loss to pre-compensate for at that point; you've already lost your signal.

    The antenna's gonna get you all the signal you can get. Now the job of the pre-amp, any other amplifiers is to get as much of that signal as possible to your receiver; without decreasing or only minimally decreasing the signal-to-noise ratio.
     

Share This Page