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| Get a load of this: I'm connecting a Dish Network receiver to a whole-house distribution via RF coax. The local channels come in perfectly via an OTA antenna. Because one of the broadcast stations is Channel 3, I need to modulate the RF output from the Dish receiver to another channel, preferably UHF. That is, using the channel 4 output results in interference on channel 3, and the opposite is true also--the broadcast of channel 3 interferes with channel 4. No big deal. So I get a simple modulator andd I arbitrarily set it to channel 19. I connect all the wires from the Dish box to the modulator. (It works with composite video and right/left audio. Very simple.) The modulated signal (which is now RF) then passes through a 3-way splitter: One to the kitchen, one to the bedroom, one to the basement. I went into the kitchen and tuned the TV to channel 19, and everything works perfectly--nice picture, sound, the works. It functions exactly as I thought it would. I can scan through the "air" channels and right there on channel 19 is Dish Network. Perfect. Here's where it gets weird: The bedroom TV and the basement TV (which, in theory, are receiving the exact same RF signal) produce no audio--the Dish Network picture is there (and very clear), but there's no sound whatsoever. What do you think is going on? |
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Derek | Does you modulator have provisions for fine tuning? The TV in the kitchen may have an exceptional Phase Lock Loop or Automatic Gain Control and is capturing a slightly off signal. I would also try taking the bathroom TV into the kitchen and trying it there. Maybee a slight difference in cable length is tripping the other TV up. Finally try another brand of modulator. See http://www.partsexpress.com/webpage.cfm?webpage_id=3&SO=2&&DID=7&CATID=55&ObjectGroup_ID=530. Hope this helps. |
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| I finally figured it out--an inline amplifier providing a 12dB boost solved the problem entirely. I think what may have been happening was that the signal was fairly weak (even though the picture was decent) and the audio was being "squelched" by the circuitry of the newer TVs. The oldest TV was the one that always worked, so perhaps its age and lack of noise suppression circuitry combined with the fact that it was the set with the shortest cable run could explain the whole phenomenon. With the addition of the amplifier, all of the video is even clearer, and the audio comes on in all the rooms. Problem solved. Thanks for helping out, Derek! |