Backfeed signal from TiVo HD through existing coax

[BrennanU]

Hi. I have a TiVo HD fed by cable. I have heard about other users back feeding their video output from their TiVo to the rest of the TVs in the house. How is this done, and what would I need to do it. Also, our cable co is going all digital soon if this helps or hinders the situation. The converter boxes do have analog pass through when they are turned off.

[DrewTivo]

I believe they do that using the HDMI output (or component) in combination with a splitter. There's no coax output from a tivo HD.

[BrennanU]

I was figuring I need some sort of RF modulator, but I was wondering the specific equipment to keep the signal from leaving the house and to get the signal off of that channel.
Brennan

[bkdtv]

There are distribution hubs that will split a HDMI signal and send it over coax. These tend to be pretty expensive. I know Gefen (http://www.gefen.com) sells a few, but I think there is a cheaper alternative out there somewhere.

If you only need to access one TiVo in your home at any given time, then another alternative is Slingcatcher. A Slingcatcher duplicates the audio, video, and remote of a TiVo on other TVs in your home using your home network. You would have a set of unused outputs on your TivoHD connected to a Slingbox, and then one Slingcatcher on every other TV in your home. More information here:

http://www.slingmedia.com/go/slingcatcher-slingplayer

Slingcatcher can work over a wireless and wired networks. It can also work over MoCA (fast ethernet over coax) networks.

[mattack]

You can use a VCR (even a 'broken' VCR that won't actually play tapes) to take A/V inputs and output over coax.. But it will always be mono and you will have worse than composite quality video.

A VCR is the cheapest RF modulator that people likely already have though.. plus that's a fair mount of power to waste all the time for that purpose.

[BrennanU]

Can I just buy a regular RF Modulator for composite/S-Video to coax at Radio Shack? If so, what will I need to keep the signal from leaking out to the rest of the cable system. If we are all digital, there shouldnt be anything on that channel I am guessing. But, could they use those frequencies for something else?

[classicsat]

You can buy a straight RF modulator. You will distribute it using its own coax though.

[wkearney99]

You can buy a straight RF modulator. You will distribute it using its own coax though.

Not necessarily. You could get something like a channelmaster RF modulator that allows selecting an RF channel. Not just channel 3 or 4. Pick a channel that's unused on the cable. Or add a filter to block just that channel's frequency. Then you can put your channel straight onto the same wire. The trouble will be, however, in getting each set out there to see it. If you're using set top boxes those will probably only show channels set up from the cable company. You'd have to bypass the box and tune that analog channel directly on the TVs. Depending on the coax setup that may not be practical/possible.

Then there's the question of controlling the source. How are you going to change the channel or otherwise control the source Tivo? You'd have to get into using an RF capable remote or deal with devices that 'distribute' the IR signal back to the source, often over the coax itself.

Yes, you 'can' do this but given the complexities in setting it up AND the hassles of day to day use (do not overlook the WAF "Wife Acceptance Factor") you may decide it's not worth jumping though the hoops.

That and by using an RF channel you're stuck with a pretty poor picture. At this point nobody's selling an ATSC modulator (at least not at a reasonable price point).

[BrennanU]

The cable boxes all have analog pass-through, so it would be just a matter of turning off the box to see the channel. Do I have to worry about the frequency being used on the cable, or backfeeding to the whole cable system? I think that any analog channel should be free due to the all digital setup.

Edit: Also, the picture quality shouldnt be an issue as all of the tvs are standard definition. In addition, we do have a remote extender already being used so the remote is taken care of.

[wkearney99]

The analog box pass through is an extra step, mind the WAF. But then so is tuning to a 'special' channel to just get the internally 'broadcast' channel.

Many cable networks have and will continue to have analog channels on them.

You put a filter on it to block that channel coming in from cable. That leaves it free for you to put something else in it's place. If you're sure there's nothing on the channel you want to use (that is, that your modulator can create) then you could get by without one, but I wouldn't as cable providers are notoriously inconsistent as to what they deliver, on what channels and when. Putting on a filter just guarantees you won't get disrupted by surprise (again, toeing to the WAF risks).

[BrennanU]

They have informed us that there will be no analog channels, so I am thinking that if I just output on channel 3, the same channel the box outputs on, whenever I turn off the box, I will be on the TiVo channel. As for reliability, I don't think it will be an issue, as this won't be a frequently used feature, just on certain occasions that we are in the workout room or something and want to watch a recorded show. About my only concern is if I will get in trouble from the cable co because my channel is back feeding to the rest of the neighborhood, or on the same frequency as some other important channel. Or, is that filter that was mentioned what prevents back feed? Also, where would I find a filter?

[classicsat]

You would have to trap out CH 2-3-4 from the source (and use an bi-directional amplifier perhaps), and you would not get what channels are sent on those channels.

That is why I say to use a second coax for the TiVo signal.

[ZeoTiVo]

I had stuff from www.crossbarmedia.com that worked pretty well and let me pick the channel to output on and a filter to keep those channels out of the house and my stuff from going out of the house. Also sent the remote commands over the COAX as well so that eliminated any RF interference problems.

Over time I found that having a TiVo at each TV offered more choice in the form of extra tuners and so forth.

For a while longer I had it setup on a Tivo with DVD to output the DVD playback but then moved on to ripping the DVDs to a PC hard drive nad using TiVo To Come Back to pull the movies onto the TiVo where I would watch the movie.

having the extra TiVo DVRs cost more but are worth it to me in the terms of ease of use and flexibility

[BrennanU]

I don't mean to keep asking the same questions, but what do I need to filter out if there are no analog cable channels?

[LoREvanescence]

I don't mean to keep asking the same questions, but what do I need to filter out if there are no analog cable channels?

the cable co's make use of pretty much every frequency. even though you think it is not being used. It could still have your digital channels, sports packages ppv, on demand and what not in place on that frequency. So with out filtering it, you wont get a clean signal with your output.

[chip_r]

Assuming that your local cable system is digital-only, they're still free to use the analog frequencies. You don't want your modulated analog frequency to go out of your house (unless you want your neighbors to enjoy your Tivo) and you don't want any signals at your modulated analog frequency in. It's possible that it's a FCC-type concern if you start shipping signals from your house. In general, keep your modulated signals in your house regardless of the local cable system format (NTSC or QAM).

[BrennanU]

So, a filter will also serve to stop the signal from going out of the house? Where would I find such a filter?

[ZeoTiVo]

So, a filter will also serve to stop the signal from going out of the house? Where would I find such a filter?

read up on all this at the site I linked www.crossbarmedia.com

you do not need to buy anything there but they have a very clear explanation of the whole process - you will just have to read a bit.

[chip_r]

This site (http://www.smarthome.com/_/ProductResults.aspx?Ntt=notch%20filter) has a handful of notch filters to block out specific channel bands. I believe the idea is that you can use a distribution amplifier with an RF modulator input and add in your own modulated channel at lets say channel 78. Using a notch filter that blocks channels 75-80 on your cable co. feed, insures that your modulated video won't go back on the line and if the cable co. has video in that range, it won't interfere with your local signal. Anyone in your house just tunes to channel 78 and they can get the video.

If your local cable co. is digital only, then your NTSC modulated signal wouldn't interfere with their QAM anyway (which, I believe, is your question) but you really don't want to ship out your video to the neighborhood. The filter is cheap (compared to the amplifier and modulator).

This does bring up an interesting thought ... the filter would also notch out any QAM carriers so I suspect you might lose a few digital channels in the process with the filter.

[wkearney99]

That is why I say to use a second coax for the TiVo signal.

Which continues to be less-than-useful (if not outright BAD) advice. There's absolutely no need to go through the hassle and expense of adding a second set of cabling. Not without already knowing there aren't any frequencies available to inject your own signal. And even if the cable company is using "all" the frequencies you can simply choose which one to block (using a filter) and then modulate onto it. Simple, and uses the same wire.

The filters are bidirectional, what you block from coming in is also blocked from going out.

An amplifier may or may not be necessary depending on the modulator being used and the quality and layout of wiring in place. It's often easiest to simply try it first and only add an amp if absolutely necessary. If it's REALLY poorly carried without an amp then you MAY be in a situation that could benefit from added wiring. But until you know that, why waste the effort/money?