Tivo not accepting IR repeater feed

Discussion in 'TiVo Help Center' started by Remellay, Nov 7, 2011.

  1. Remellay

    Remellay New Member

    Nov 7, 2011


    My Tivo XL Premiere will not accept instruction from my theater room. The device is located in the basement below the theater. It was installed in March 2011 without problems until this past weekend (Nov 5, 2011)

    I've ruled out the remote. It does not respond to either the universal nor Tivo remote. It will however respond when I go to the basement and activate either remote in close proximity.

    Other devices that make up the home theater include an AV receiver and blue ray player. They are in the same location as the Tivo box. They do accept input from the theater room. Therfore I can intuitively rule out the repeater. BTW, this is a Channel Vision IR 5000.

    That leaves the individual emitter as the sole culprit. I did remove the emitter from the blue ray and attach it to the Tivo box. I assumed the emitter was dumb, it did not care which device it was attached to. But alas this did not resolve the problem.

    Has anyone experienced this same problem? In the troubleshooting process, I think I have intuitively ruled out everything. The only thing I can think of know is the Tivo box is more sensitive to the emitter.

  2. yjr

    yjr New Member

    Apr 26, 2006
    This is a long shot.
    I ran into something similar few years ago.
    Do you by any chance use compact flourescent lighting in either your home theater or Tivo locations?
    CF bulbs tend to emit a lot of IR energy overloading the equip. IR recvrs.
  3. lrhorer

    lrhorer Active Member

    Aug 31, 2003
    This is false. CF bulbs, and fluorescent bulbs in genreral do *NOT* produce a lot of IR. Indeed, this is the entire point of using a fluorescent light source, particularly a CF source, for general purpose lighting. Up to 90% of the energy produced by an incandescent lamp can be infrared. By comparison, typically less than 20% of the CF bulb's spectrum is IR, and it's overall power dissipation is much less, causing its IR output to be much, much lower than an incandescent bulb. What is much, much higher is the RF and AF output of the CF bulb. Unless on a dimmer, incandescent bulbs produce almost no RF at all, and the only AF they produce is a modest 120Hz signal caused by the cooling of the filament every time the amplitude of the AC input signal drops toward 0 volts.

    So how do they interfere with IR receivers? The answer is "IR" receivers aren't really IR. It is the transmitter that is IR, having a very specific, fairly monochromatic output in the IR spectrum above 650nm. The receiver's photoreceptor, however (usually a phototransistor) has a very wide range of sensitivity, usually from low IR through visible light and even well into UV. While a steady stream of photons from even a visible light source will be detected by the phototransistor, its collector is capacitively coupled to the IR detector's input, so that steady light emissions don't usually effect the receiver, unless the light source is so powerful that it completely saturates the photoreceptor, leaving it unable to pass anything at all. It is not the CF bulb's output wavelength that is the problem, but rather the modulation frequency of the light output. CF bulbs employ a high frequency ballast whose sidebands can pass through the coupler to the detector input circuitry, causing problems with the receiver.

    Here is a link to a site showing the typical spectrum of traditional fluorescent and CF light sources. As you can see, there is almost nothing above 650nm (red light).

    Compare that with the chart at the top of this link, showing that almost all of an incandescent bulb's emissions are longer than 650nm. Quartz-halogen bulbs, having a hotter filament, are somewhat better, but neither one has anywhere nearly as low an amplitude spectrum in the IR range as a CF bulb.
  4. lrhorer

    lrhorer Active Member

    Aug 31, 2003
    How close? Do they have a normal sensitivity when the remote is taken downstairs, or do you have to be very close.

    Not necessarily. It may be having a problem with the modulation frequency, or something else specific to the TiVo modulation.

    This suggests it is not the emitter. Yes, the emitter should be dumb.

    Does the IR indicator on the TiVo flash or flicker even if no remote button is being pressed? Try covering the emitter and the TiVo togetehr with aluminum foil, excluding all light but that from the emitter. Does that make a difference?

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