# Using DECA over Comcast Cable



## mogulman (Mar 19, 2007)

Ok.. I realize this may be unsupported...

I have my Comcast Cable (internet) and Directv come into my house at around the same place.

The Cable internet goes up to my office where my cable modem, Router, etc is...

Directv feeds the TVs. There is no Directv in my office where the internet is.

If I hook up my Directv DVRs using the DECA system is there any way to do the following:

-Connect DECA to my Home internet upstairs? Can I use a DECA near my Cable Modem and have the DECA signal use my cable back down from my cable modem, and then some how bridge over using another deca to the Directv cable where they are close?

- maybe run a directv line up to my home office just for the DECA - Ethernet connection? Is this part of the normal install? Will I have all kinds of wires on the outside of my house for this?

any other ideas?

Unless I can get the DECA stuff hooked up to my home internet there doesn't seem to be much reason to use it for me.

Oh..one other thing. If I did finally get this hooked up. Is there any way to use the DECA network in my Den to hook up my HTPC and PS3? I realize this isn't optimal as far a Directv is concerned, but what would I need for the DECA, near that receiver? Just hook the ethernet port up to a switch that I have there?


----------



## veryoldschool (Dec 10, 2006)

Simply answer is you can't use DECA on your Cable coax.
You can run another coax to your router and have a DECA there connect to it for internet access.
Trying to leverage your DECA network for other networking needs may work, but shouldn't be done, because DECA is supported, but by adding other devices on it that aren't DirecTV's, you negating the support.


----------



## mogulman (Mar 19, 2007)

I don't care so much about the support. I usually do my own thing. 

Just trying to see if DECA would be useful for me. Right now I'm using Wireless-N down to my HTPC, and I have my two DIRECTV boxes wired together using a switch and then connected to the rest of the network using Wireless-N. If I can somehow eliminate the Wireless piece, and connect up to my network/internet then DECA would be interesting to me.


----------



## evan_s (Mar 4, 2008)

Deca is designed to avoid the frequencies DirecTV uses and is centered around ~550mhz which is in the range normally used by Cable Companies. MOCA (which is basically the same thing as DeCA, just a different frequency) is typically run at ~1.1ghz which is outside of the usual cable range but right in the middle of the DirecTV range.

You might manage to run deca over the same cable as your Cable modem but it is likely to cause problems and even if does work for a while it could stop working at any time.


----------



## mogulman (Mar 19, 2007)

So what if I did this:

MOCA device near my Cable modem, with ethernet connected to my Router. This gets the IP traffic on my Cable line.

Then another MOCA device near the entry of the cable into my house, connecting the Ethernet of this MOCA device to the ethernet Port on a DECA device, which is then connected to one of the unused COAX cables from my Sat Dish. This would allow me to transport using MOCA over my Cable Coax down to where the SAT connection is closer, then connect MOCA to DECA using an ethernet cable?


----------



## Spanky_Partain (Dec 7, 2006)

If done correctly, then yes it could work.

This looks to be getting rather pricey! 

The DECA device would need a power supply to as shown in this image.


----------



## evan_s (Mar 4, 2008)

Yes that should work but it is not going to be cheap. Probably cheaper to just run some Ethernet to a better location.


----------



## VLaslow (Aug 16, 2006)

veryoldschool said:


> Simply answer is you can't use DECA on your Cable coax.
> 
> So that means that my cable backup signal for my QAM tunermight not work if a DECA were attached to it (Time Warner Cable).


----------



## bobnielsen (Jun 29, 2006)

VLaslow said:


> veryoldschool said:
> 
> 
> > Simply answer is you can't use DECA on your Cable coax.
> ...


----------



## veryoldschool (Dec 10, 2006)

VLaslow said:


> So that means that my cable backup signal for my QAM tunermight not work if a DECA were attached to it (Time Warner Cable).





bobnielsen said:


> It would probably work at frequencies outside the 500-600 MHz range (channels 19-35), maybe a few more. You might need a bandstop filter on the tuner input.


Cable normally goes up to close to 900 MHz and may only be around 15 dBmV or less.
DECA can be 49 dBmV and uses the 500-600 MHz band, plus the SWiM comm @ 2.3 MHz.
This kind of points to losing a few channels along with needing to block the DECA going out the cable, which Time Warner wouldn't be happy if you don't.


----------



## bobnielsen (Jun 29, 2006)

veryoldschool said:


> Cable normally goes up to close to 900 MHz and may only be around 15 dBmV or less.
> DECA can be 49 dBmV and uses the 500-600 MHz band, plus the SWiM comm @ 2.3 MHz.
> This kind of points to losing a few channels along with needing to block the DECA going out the cable, which Time Warner wouldn't be happy if you don't.


Nor would other cable customers


----------

