Distribution modulators and digital cable - AVS Forum
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post #1 of 6 Old 06-05-2001, 12:49 PM - Thread Starter
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I am interested in using a modulator to distribute my TiVo and DVD output to other rooms. Does anybody know if this will work with AT&T digital cable? I'm concerned that a modulator may whack some of the digital channels.

If it makes any difference, I am on one of the old two cable A/B systems. I can't even get things like the NFL or NHL sports packages since the bandwidth is all used up by the standard cable offerings (analog and digital).

I apologize if this is a repeat question, but I did a search and came up empty... Thanks in advance.

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1) Phillips 14hr hacked to 106hrs - v2.0.1-002
2) Phillips 14hr hacked to 63hrs - v2.0.1-001

-Greg
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post #2 of 6 Old 06-06-2001, 12:10 PM
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I don't think a modulator will work with digital cable. The modulator adds an analog channel to an analog video signal. The cable actually has a digital signal. I would be very surprised if it worked.

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post #3 of 6 Old 06-06-2001, 12:37 PM - Thread Starter
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Here's my understanding after some more research between yesterday and today:

Digital cable still uses the same analog cable channel frequency slots, but it packs in several digitally encoded channels per slot. My system actually still has 70 analog channels that can be viewed without a cable box (split between two physical cables) and then maybe another 100 or so digital channels.

So, my new question is, can I get a modulator that will modulate to a channel that is high enough to be above the last used channel or even use the UHF band as an alternate? I really don't want to loose any of the digital channels since I am subscribed to the premium service and get them all (movies, movies, and more movies!!!!).

I'm also wondering if it may help that I have an old A/B cable system. My assumption is that the cable company would be using a much smaller range on each one and I could more easily get above the channels used by them.

Opinions?

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1) Phillips 14hr hacked to 106hrs - v2.0.1-002
2) Phillips 14hr hacked to 63hrs - v2.0.1-001

-Greg
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post #4 of 6 Old 06-06-2001, 02:08 PM
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Typically, cable operators put digital cable information in a 550MHz to 750MHz band. That leaves 750MHz to 806MHz (the top of UHF) in which you may modulate an analog video signal. Sometimes there is also clear spectrum between 470MHz and 550MHz. Sometimes the cable operators will put test tones or inadvertently broadcast junk on what should be clear spectrum.

(For a chart on frequencies and channel numbering, go to our web site http://www.channelplus.com/AP_note_f...0spectrum.htm)

Try tuning a TV to a candidate channel assignment. If you have snow (and nothing but snow) you have a shot at creating a locally modulated channel on that channel number.

If you get interference, you may need a filter to clear out the junk. A 750MHz low pass will allow digital cable to still work and give you space for a couple of locally modulated channels.

If you can determine that one of the two cables does not have the digital information on it, you should have lots of opportunities to add your TIVO channel.

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Rich Foye
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post #5 of 6 Old 06-06-2001, 02:11 PM
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Sorry, delete the paranthesis in the URL http://www.channelplus.com/AP_note_f...20spectrum.htm



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post #6 of 6 Old 06-06-2001, 02:50 PM - Thread Starter
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Thank you for the info! Now that I know I have a decent chance at finding an open channel, its time to try and convince the finance manager to let me do it. I think the TiVo purchase is still too fresh in her mind.... http://www.avsforum.com/ubb/smile.gif

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1) Phillips 14hr hacked to 106hrs - v2.0.1-002
2) Phillips 14hr hacked to 63hrs - v2.0.1-001

-Greg
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