# Combining 522 TV2 feed with Comcast Digital Cable Signals



## Shakti (Feb 2, 2006)

Folks, I am finding this to be a challenge. Comcast provides their basic and expanded digital package as part of a commercial account package. I do not have a comcast box but I do have a TV with a digital tuner and on hooking their cable to the "cable" input of my TV was able to tune to several analog and digital channels. 

Okay now the issue, I have two cable runs in every room and the 2nd cable run was primarily used for the TV2 backfeed from the 522 to all my TV's. with the introduction of Comcast digital service, I want to combine the comcast signal and the 522 and send it through the same cable (The second cable run is exclusively used by the Sat signal to the receiver in each room). 

In the stand alone configuration, the 522 feed was set to 90 (cable), in the stand alone configuration there is no comcast digital signal at 90.
Using a combiner/splitter I have combined the two signals (522 TV2 feed and Comcast signal) and then at the TV hooked up the combined signal to the cable input of the TV hoping to get the 522 TV2 feed on 90 + the other channels broadcast by comcast, NO LUCK. Tried other ranges 91, 100 95 etc...still no luck

I switched the 522 feed from the cable to air to use the 21-69. Still no luck. Remember the input to the TV is still on the cable RF input. Do you think I have to split the cable before it goes to the TV, so that the 522 signal goes to the ANT input and the Comcast cable signal goes to the Cable input

Any clues as to what I am doing wrong

The only other alternative is to use the 2nd line I have for satellite and then using a combination of diplexors (input and output) combine/split the SAT signal and the 522 TV2 feed and use the AIR channel range (21-69) and connect that to the ANT input of the TV...(the Cable input will be occupied by the Comcast signal feed)

Other info
Comcast Cable broadcasts on every channel from 2-85 and all the digital sub channels (I don't get most of them). I am assuming range 90-100 is clear but can't tell since there maybe some digital signal being send by Comcast and sicne I don't have a cable box I can't get it. My TV's digital tuner atleast cannot tune to anything in the 90-100 range hence the range used by me for the 522 TV2 feed


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## Mavrick (Feb 1, 2006)

I think that you are going to have to use diplexors in the equation somewhere for I dont think that using just combiner/splitter can successful combine the 2 signals.

This said with them both being digital it may not be possible at all I really don't know for sure for I have not tried this combo but if they both operate on the same Freq. the Dish may cancel out the digital cable.


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## drjake (Jun 12, 2002)

You need to get a filter that blocks out the Comcast digital signal where you want to put the channel. Channel Plus makes filters. Do a google search and you should find them. You'll probably want to usa a notch filter rather than a low pass filter as the lowpass will block everything above the frequency level which will knock out the digital channels. A notch filter blocks out a few channels and nothing more.


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## Shakti (Feb 2, 2006)

Okay a basic question, what is the difference between the modualtor AIR range and the CABLE range. Does this in anyway relate to how I need to connect the coax cable to either my ANT input on the TV versus the CABLE input on my TV
More specifically if I set the modulator to AIR should I connect the coax to the ANT input and vice versa

Also drjake what is the relation between the frequency and the number selected in either AIR or CABLE modulator mode

Thanks for the quick replies


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## drjake (Jun 12, 2002)

Shakti said:


> Okay a basic question, what is the difference between the modualtor AIR range and the CABLE range. Does this in anyway relate to how I need to connect the coax cable to either my ANT input on the TV versus the CABLE input on my TV
> More specifically if I set the modulator to AIR should I connect the coax to the ANT input and vice versa
> 
> Also drjake what is the relation between the frequency and the number selected in either AIR or CABLE modulator mode
> ...


AIR means it is using UHF channels, Cable means if is using the cable channels. I doubt that Cable and Ant really would result in a different reception of channels but they might. Ant would cover the normal VHF (2-13) and UHF channels (14-69) and cable would include the cable channels (note that cable channels include the VHF band among others).

The relationship between frequency and channel can be determined by using frequency / channel charts. The channel plus filters will typically reference a frequency range but the channels that are blocked and/or allowed to pass typically listed in the information regarding the filters. Notch filters typically block a few channels in eaither the UHF or mid cable range. Lowpass filters block channels above a certain level (e.g. everything above 115 is blocked). A highpass filter would block all channels below a certain level.


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