Will this work?

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chipwells

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Sep 12, 2004
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I believe I have a solution that will allow me to combine a satellite signal for an HD receiver with modulated output from two DirecTivos over one run of coax.

I have 2 DirecTivos in my basement that will be modulated (let's say to channels 60 and 120) and distributed throughout the house through a simple panel. I plan to add an HD receiver to my family room and want to get to the DTivos as well. Since there is only one cable run from my basement I either have to add a cable run to that room from the dish (an eyesore on the outside of the house and a cumbersome run at best) or figure out a way to combine signals onto the one coax from the basement. I believe the following solution will work but want to confirm. If it doesn't work I will have the installer for the HD system make the additional run while he is onsite (and at Directvs cost).

Can I combine the modulated signal for the family room out of the distribution panel with the satellite input to the HD receiver through a diplexer on on the single run of coax? The signal would then be split out on the other end again with another diplexer and the separated runs would go to the HD receiver and directly to the TV. If I can do this I can view HD on my TV and also (through RF extension) get to the Tivo units in my basement for recorded shows when desired.

BTW, the satellite signal will be coming in from a 6X8 multiswitch that combines a round dish (for locals) and a 3 LNB Oval dish. Not sure if that will make a difference. The HD Receiver will be an RCA DTC-210. The DirecTivos will be RCA DVR80.

(I tried a rough schematic but it didn't show clearly)

Thanks in advance for any help you can provide.
 
Short answer: Yes it will.

Long Answer: Modulating the outputs of your two tivos and creating channel assignments is very similar to what a cable company does for basic analog cable. Your configuration will be well below the 1000MHz frequency where OTA/Cable end (5-900MHz) and Satellite begins (1000-2300MHz). Using the diplexers to put both frequency ranges on the same cable is what the diplexer was invented for.
 
That's what I thought. Thank you.

Any "gotcha's" I should watch out for? Signal loss, intereference, other?

Thanks again.
 
Only considerations i can think of is how you are going to mod and combine the two signals and if you are placing an OTA to the mix. I've seen mixed results with standard mods (http://www.pacemso.com/attachments/mod1.pdf) simply reversed into a splitter and tieing that to the diplexer.

As for distribution, if you are just going to the one room, amplification probably won't be necessary.

Interference shouldn't be a consideration if you aren't seeing any now.
 
i for one dont think the answer is correct. he is trying to eliminate the direct feed from the mulii switch / dishes, the answer would depend what side of the home the signal is travelling thru the diplexers, in put is input and out put is out put, tou CAN NOT cross flow. also you say that running the new coax would be cumbersom and difficult, remember one thing, the basic install with directv is , one dish, in most areas, mounted ON THE SIDE WALL OF THE STRUCTURE , coax thru the wall or sill plate for the first floor and for the second floor THRU the WALL, any attic crawls or wall fishes cost the subscriber , there are NO exceptions, so that cost will not be on directv you will pay extra or put on coveralls. i may be wrong and if so im sorry, but i dont think so
 
I'm not trying to eliminate the direct feed. I am simply trying to combine the direct feed out of the multiswitch with the modulated channels over the existing coax. I believe the diplexer will work because of the frequency differences, as noted.
 
robert luzzi said:
in put is input and out put is out put, tou CAN NOT cross flow

Sorry Robert, but that is exactly what diplexers are made for. Takes full advantage of the available spectrum that the cable has available.

diplexer.jpg


950-2250MHz on the IF side, 40-860MHz on the RF side in this example; which can be combined and be used bi-directionally on the same cable.
 
When I added HD and Tivo to my living room, my installers crawled under my house to add another coax and did not charge me a dime.
 
Can I assume the Eagle Aspen is a quality diplexer? As I search there are many, many different brands with a wide price range. What should I look for to make sure I get a high quality diplexer?

Thanks again for the help!!!
 
Eagle Aspen, ASKA, Perfect Vision, et al of this price range are all entry level diplexers and should work just fine for your application. They will either work, not work (1-5% out of the box) or provide fuzzy picture. The more expensive ones usually drop below 40MHz (for cable modem return path), allow power to pass on the RF side to power an OTA antenna pre-amp or are used for commercial/MDU distribution. Save your pennies for more toys, get the entry level diplexers.
 
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