Combine TV2 with CATV

[ts7]

I have been using TV2 output on 322 and 722 on channel 60. I also have Comcast for my Internet service (but also get "basic" TV which carries all of my locals w/sub-channels). I want to combine the TV2 signal with my Comcast service to feed a couple TV's that have a single coax antenna input. I believe I can use a standard splitter in reverse to accomplish this, but what will keep channel 60 from TV2 from being broadcast back out over the Comcast system?

Sorry if this has been covered elsewhere. It seems to me I've seen it but a quick search didn't come up with anything.

Thanks!

 

[codee]

As long as the splitters are hooked up correctly you will be fine, just make sure the single port is facing your TV and the side with 2 ports are where the inputs from the comcast feed and dishnet feed go. I know it sounds simple, but you'd be amazed at some of the stuff I've seen.....

Anyways, the splitters have seperation/isolation builtin to them so there won't be any backfeeding.

 

[boba]

You will have a lot of trouble receiving ch 60 if your TV's are set to receive cable channels. Ch 2-13 are the same for cable or OTA but above ch 13 cable uses different frequencies for the channel numbers.
Ch 60 on cable Hyperband is 438 mhz while Ch60 OTA UHF is 746 Mhz so a tuner set to receive CH60 now won't tune cable channels above 13 and a TV set to Cable instead of OTA won't see CH60.

 

[ts7]

You will have a lot of trouble receiving ch 60 if your TV's are set to receive cable channels. QUOTE]

It seems to me that on at least one TV, I have been able to find my Dish receiver's output even though the TV was in "cable" mode (I think it was in the 100+ range, though).

I just picked up a new splitter last night and have not had a chance to try it yet. If it doesn't work, are there any other suggestions on how to accomplish this?

Thanks

 

[highdefjeff]

You will have a lot of trouble receiving ch 60 if your TV's are set to receive cable channels. QUOTE]

It seems to me that on at least one TV, I have been able to find my Dish receiver's output even though the TV was in "cable" mode (I think it was in the 100+ range, though).

I just picked up a new splitter last night and have not had a chance to try it yet. If it doesn't work, are there any other suggestions on how to accomplish this?

Thanks

Instead of using Air 60, change the modulated output of the TV2 to a cable channel. Pick one that is not in use on your cable channels. There are many choices starting at 73, with choices up into the 100's. Use the lowest one that is not in use, and that provides the clear picture. Start with Cable 73 and work your way up until you find the "free and clear" channel to use.

TV2 Tips & Tricks

 

[harshness]

Experimentation is required because everyone's cable system uses their bandwidth differently. You should choose CATV channels as suggested, but there's no way to tell what might get whacked by digital channels or cable modem channels without trying it.

 

[tbarney]

I use two different products to do exactly what you are describing. First, a product like the Channel Plus NF-471 here: [ame="http://www.amazon.com/CHANNEL-PLUS-LPF-470-Pass-Filter/dp/B00006JPE0/ref=sr_1_1?ie=UTF8&s=electronics&qid=1230400154&sr=8-1"]this [/ame]which cleans the line of high cable channels that no one watches. In most cases there are garbage channels in the higher range so you don't want them on the line. In the case of the Channel Plus NF-471 that is in the linked above, it Blocks CATV Channels 75 - 80. There are other filters which block different channel ranges

Then you can either use splitters as described in other posts above, or what I have which is the Channel Plus 3025 video distribution system. It takes your cable TV and your Dish TV2 ouput and join them into a single cable. That can be found here: [ame="http://www.amazon.com/Channel-Plus-Multiroom-Distribution-Modulator/dp/B00006JPED/ref=pd_bbs_sr_1?ie=UTF8&s=electronics&qid=1230400337&sr=8-1"]here[/ame]

All together, you can do it for under $125 and get a perfect singal, with built in amplification to send it to a few different TVs.

 

[garys]

I use two different products to do exactly what you are describing. First, a product like the Channel Plus NF-471 here: this which cleans the line of high cable channels that no one watches. In most cases there are garbage channels in the higher range so you don't want them on the line. In the case of the Channel Plus NF-471 that is in the linked above, it Blocks CATV Channels 75 - 80. There are other filters which block different channel ranges

Then you can either use splitters as described in other posts above, or what I have which is the Channel Plus 3025 video distribution system. It takes your cable TV and your Dish TV2 ouput and join them into a single cable. That can be found here: here

All together, you can do it for under $125 and get a perfect singal, with built in amplification to send it to a few different TVs.

Looks like a pricey solution to an easy setup. I used a couple of inexpensive splitters and removed the unwanted channels to get the same result.

 

[ts7]

After trying three different splitters (different frequency ranges), changing my 322 from "air" to "cable", trying virtually every channel available in both ranges, I have yet to find a workable solution using just splitters. Running just cable through the splitter works great and running just the TV2 RF output through the splitter works great, but as soon as I connect both cable and TV2 to the splitter, things stop working. Some combinations work better than others, but I can't find a combination that doesn't result in snowy picture on the TV2 output or loss of digital signals on the cable. My conclusion is that either Comcast is totally exploiting all available cable AND UHF spectrum and/or the modulator on my 322 is bleeding RF way outside the specified channel.

tbarney may have proposed a somewhat pricey solution to what should be an easy set up, but at this point that may be all that will work.

If anyone has any other ideas, I'm all ears, but thanks to all who offered suggestions and advice!

 

[garys]

Do you get the same result whether the 322 is on or off?

 

[PBX_Guy]

Looks like a pricey solution to an easy setup. I used a couple of inexpensive splitters and removed the unwanted channels to get the same result.

Agreed. tbarney used a sledgehammer to kill a fly and paid dearly. 10 bux covered it in my house w/sufficient port-to-port isolation to make unwanted backfeed a non-issue. Some would argue there's still some residual signal there, to which I would argue yes, but it's really down in the soup and will be further attenuated (better than -40 db down) when it hits the cable Mul-Tee in the back yard.

 

[boba]

Most cable companies run a carrier on all channels which without filtration to remove the carrier gives the problem you are seeing. The only solution that is economical is 2 lines and an A?B switch. As you have been told it can be done but not at a price you apparently want to pay

 

[PBX_Guy]

After trying three different splitters (different frequency ranges), changing my 322 from "air" to "cable", trying virtually every channel available in both ranges, I have yet to find a workable solution using just splitters. Running just cable through the splitter works great and running just the TV2 RF output through the splitter works great, but as soon as I connect both cable and TV2 to the splitter, things stop working. Some combinations work better than others, but I can't find a combination that doesn't result in snowy picture on the TV2 output or loss of digital signals on the cable. My conclusion is that either Comcast is totally exploiting all available cable AND UHF spectrum and/or the modulator on my 322 is bleeding RF way outside the specified channel.

tbarney may have proposed a somewhat pricey solution to what should be an easy set up, but at this point that may be all that will work.

If anyone has any other ideas, I'm all ears, but thanks to all who offered suggestions and advice!

Bear in mind that the splitter has high loss port-to-port (between the two output ports) but only 3db in either forward or reverse (between the input port and either one of the 2 output ports (assume std 2x splitter). You want to connect the splitter input port to the 2nd room TV, then connect the 2nd room output (from the receiver) to one of the output ports of the splitter and connect your cable TV signal to the other output port. Do it any other way and you'll have snowy pix.

An A/B switch is another way to do it, almost as cheap

 

[harshness]

Cable is pretty much free to pollute the entire frequency band as long as it is a closed-loop system. With fiber to the neighborhood, that band can be pretty wide. That's why there has been at least one recommendation of a tank/trap.

The Channel Plus solutions are pretty much plug and play, but there are passive (require no power) "CATV bandpass filters" that will work well enough when properly placed that cost under $25.

DOCSIS 2.0, the current cable modem standard, covers frequencies from 5MHz to 860MHz (up to CATV 135) but if you block out a range, your modem will likely negotiate a frequency outside of that range to establish a link (birdies happen).

 

[ts7]

Do you get the same result whether the 322 is on or off?

I would not have expected this to make a difference, but it certainly did. I get the same result when the 322 is on or off. Further investigation showed that even with the TV2 coax disconnected from the 322 I had the same interference when I had the coax on the splitter side connected. This certainly makes it look like I may have an issue with my cable plant, but I can't figure out why it would work fine connected directly - I've seen ground loops before, but this doesn't look like a ground loop issue. I'm going to have to do some more testing.

Bear in mind that the splitter has high loss port-to-port (between the two output ports) but only 3db in either forward or reverse (between the input port and either one of the 2 output ports (assume std 2x splitter). You want to connect the splitter input port to the 2nd room TV, then connect the 2nd room output (from the receiver) to one of the output ports of the splitter and connect your cable TV signal to the other output port. Do it any other way and you'll have snowy pix.

An A/B switch is another way to do it, almost as cheap

The splitter is connected in "reverse" (input to TV, outputs to cable and TV2) so that is not a problem. A/B switch is an inexpensive, though inconvenient, option but should work.

Cable is pretty much free to pollute the entire frequency band as long as it is a closed-loop system. With fiber to the neighborhood, that band can be pretty wide. That's why there has been at least one recommendation of a tank/trap.

The Channel Plus solutions are pretty much plug and play, but there are passive (require no power) "CATV bandpass filters" that will work well enough when properly placed that cost under $25.

DOCSIS 2.0, the current cable modem standard, covers frequencies from 5MHz to 860MHz (up to CATV 135) but if you block out a range, your modem will likely negotiate a frequency outside of that range to establish a link (birdies happen).

I have a tap at the service entrance for my cable Internet so it would be easy to filter anything for the entire house without interferring with my Internet connection.

I like the Channel Plus solutions (though they are a bit pricey when compared to a simple splitter, A/B switch or bandpass filter) but I'm planning on doing some remodeling soon and will hopefully revamp the entire cable plant in the house at that time so I hate to sink much money in to a solution before then.

For now I will troubleshoot my wiring (if anyone has any suggestions on this - other than the obvious broken/damaged cable or bad connector - please contribute!) and if that doesn't fix the problem I will probably opt for the A/B switch and go with a higher-end solution when I re-wire.

Thanks again for all the help and suggestions!

 

[garys]

Could be the problem is with the splitter, can you exchange it with another one?

 

[ts7]

Could be the problem is with the splitter, can you exchange it with another one?

Yes, I've tried three different splitters from three different manufacturers with identical results.

I'm pretty sure the signal into the splitter from Comcast is too weak (or being attenuated at the higher end due to old cable).

Thanks!