# OTA antenna with diplexer for tv1/tv2 installation?



## rodent (Aug 21, 2006)

I have a ViP622 reciever fed by one coax outlet in the wall. This recieves sat signals and distributes TV2 signal to another room. I want to incorporate an outside UHF/VHF antenna to better receive HD locals.

The Dish1000 outside has one line that comes in to the house in the basement, connected to the "SAT" input on an ASKA SCS-2A Diplexer. The "UHF/VHF" output on the same diplexer runs to the TV2 (channel 62). The "IN/OUT" connector on the diplexer goes upstairs to the ViP622 reciever through the one coax outlet in the wall.

From there the signal goes to the "IN/OUT" connector on another ASKA SCS-2A Diplexer. The "SAT" output is sent to a dish sat splitter which connects to Satellite Input 1 and 2 on the back of the reciever. The "UHF/VHF" connector is connected to the "TV2 Out" on the back of the reciver (TV1 is HDMI)

This works great, TV2 is tuned to channel 62 and can view satellite programming.

How do I incorporate an OTA antenna in to my existing setup?

I am thinking I need another pair of ASKA SCS-2A Diplexers - one outside that connects the feed from the Dish1000 to the "SAT" connector and the antenna to the "VHF/UHF" connector, then the "IN/OUT" connector would continue on to the origial diplexer in the basement and connect to the "SAT" input (where the Dish1000 currently goes). At which point upstairs before the reciever does the other diplexer come in to play? I am thinking the "SAT" connector on the original upstairs diplexer would connect to the "IN/OUT" of a new ASKA SCS-2A diplexer whose "SAT" output would go to the dish splitter and the "UHF/VHF" connector would go to the "Antenna In" on the back of the reciever. Does this make sense?

Do I need to put something in-line somewhere prior to the antenna to prevent re-broadcast of dish programming (whatever TV2 is viewing on channel 62)?

See attachment for crude diagram describing current layout.

Thanks!


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## srbigbutt (Apr 25, 2005)

I think i have the same question. I currently have a 942 receiver with an OTA antenna hooked up to TV1. I am about to buy a new HD tv for TV2 and was wondering if I could split OTA to TV1 and TV2 somehow.


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## Cokeswigga (Jan 25, 2005)

You will be better off using a seperate coax for your OTA antenna. This way you won't loose signal through the splitters and diplexors that you will need to hook it up if you try to keep your current configuration.

In your basement you would have to add a splitter at the "TV2<-------Diplexor"
the single end would meet up with the UHF/VHF of your dixplexor" and the one of the other end to your OTA and the other to the TV. (and basically the same idea on the receiver end of the diplexor.
You would also have to make sure that your TV2 output was in the cable TV range so that it does not interfere with your Antenna signal. For example, I have TV1 trasmit on channel 120 and tv2 trasmit on channel 126.

Additionally.... this configuration would transmit your TV2 signals to your neighborhood which I think violates FCC Regulations.

So with that being said,

you will have better signal, less wiring mess, and no FCC interference if you run a seperata OTA cable from your antenna to the receiver.

Bad Option









Good Option


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## srbigbutt (Apr 25, 2005)

Not sure i'm following you there. What I want to do is have a splitter coming off of my OTA antenna. One going to the receiver and then the other end going to an additional diplexor that would combine the TV2 cable and the OTA cable into one cable run to TV2. That way I can watch OTA HD channels and Dish SD channels. Would this work and has anybody else done this. Any recommendations?


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## Cokeswigga (Jan 25, 2005)

srbigbutt said:


> Not sure i'm following you there. What I want to do is have a splitter coming off of my OTA antenna. One going to the receiver and then the other end going to an additional diplexor that would combine the TV2 cable and the OTA cable into one cable run to TV2. That way I can watch OTA HD channels and Dish SD channels. Would this work and has anybody else done this. Any recommendations?


Do you currently have a diplexor on your TV output?

I don't I think I understand where your dixplexor is?

see my two pix below


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## srbigbutt (Apr 25, 2005)

Cokeswigga said:


> Do you currently have a diplexor on your TV output?
> 
> I don't I think I understand where your dixplexor is?
> 
> see my two pix below


Its just like your 1st drawing but instead of just a splitter at TV2 its a 3rd diplexor that combines the Sat and antenna into one cable to tv.


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## mfabel (Jan 3, 2008)

Cokeswigga,

Thanks for the drawing. I want to do the same thing as Rodent, and although I know it is not ideal, a second cable is really not feasible for me. I am concerned about all of the loss from the antenna, so I figure I will need a decent preamp at the antenna. My antenna will probably go in the attic, so I could also put the power supply up there, or drop a line to the bedroom (by TV2) for the preamp power, where it would go back to the antenna and then to the splitter you show. Would you expect the preamp to overcome the losses?

Has anyone tried this? I'd love to hear your experiences.


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## brantlew (Mar 19, 2007)

mfabel said:


> Cokeswigga,
> 
> Thanks for the drawing. I want to do the same thing as Rodent, and although I know it is not ideal, a second cable is really not feasible for me. I am concerned about all of the loss from the antenna, so I figure I will need a decent preamp at the antenna. My antenna will probably go in the attic, so I could also put the power supply up there, or drop a line to the bedroom (by TV2) for the preamp power, where it would go back to the antenna and then to the splitter you show. Would you expect the preamp to overcome the losses?
> 
> Has anyone tried this? I'd love to hear your experiences.


I am currently doing this and

a) no you don't need to run a separate coax from the antenna to your VIP622. The additional inline hardware only adds about -7.5dB antenna signal loss which should be within tolerance as long as you within 20 or 30 miles of a city.

b) If you are really concerned with FCC guidelines, you can add a low pass RF filter between your antenna and first diplexer. You will need to match the filter frequency cutoff with the channel you choose to broadcast your TV2 out signal. This is of course, entirely optional.

If you want a diagram and more explanation check out this thread

http://www.dbstalk.com/showthread.php?p=878717#post878717


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## mfabel (Jan 3, 2008)

brantlew said:


> I am currently doing this and
> 
> a) no you don't need to run a separate coax from the antenna to your VIP622. The additional inline hardware only adds about -7.5dB antenna signal loss which should be within tolerance as long as you within 20 or 30 miles of a city.
> 
> ...


Brantlew, great to hear it is working for you. I do have some questions about your setup. I can follow your signal paths and see how it works, but I am wondering if it could be done without two of the diplexers. It is not clear to me that you need to diplex the antenna signal with the Satellite signal, and then use a second diplexer to separate antenna and satellite at TV2. See the modified drawing I am attaching. Maybe the diplexers are there for your specific physical configuration, or am I missing something?


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## brantlew (Mar 19, 2007)

mfabel said:


> Brantlew, great to hear it is working for you. I do have some questions about your setup. I can follow your signal paths and see how it works, but I am wondering if it could be done without two of the diplexers. It is not clear to me that you need to diplex the antenna signal with the Satellite signal, and then use a second diplexer to separate antenna and satellite at TV2. See the modified drawing I am attaching. Maybe the diplexers are there for your specific physical configuration, or am I missing something?


Sure that works even better, but you will need to run coax cable from the antenna to your cable box. Running cable is often a pain in the ass so the original drawing was for lazy people like me that don't want to do it and just use the existing lines that were put in by the satellite installer.


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## mfabel (Jan 3, 2008)

brantlew said:


> Sure that works even better, but you will need to run coax cable from the antenna to your cable box. Running cable is often a pain in the ass so the original drawing was for lazy people like me that don't want to do it and just use the existing lines that were put in by the satellite installer.


OK, now I am really confused. There is no new coax from the antenna to the cable box in my diagram. Only from the antenna to a new splitter near my satellite. Then the signal goes through a diplexer, single cable to cable box, where the second diplexer splits it out. I'm not sure why you would need the second set of diplexers in your diagram, but both diagrams only have a single coax to the cable box.


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## mfabel (Jan 3, 2008)

I just thought of a possible explanation - when you say I would need a second coax to my cable box, what do you mean by "cable box"? I was being loose in my terms, and assuming you meant my VIP722, but maybe you are referring to a distribution box you have somewhere in your house. If so, that would explain why you use the additional set of diplexers to avoid a new cable run. I do not have anything like that, so my current diplexer is right by the dish, and very close to where the antenna would go.


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## Cokeswigga (Jan 25, 2005)

Make it easy for us...... draw a diagram of your house... with exsiting cables, and the location of your TV's and set-top boxes


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## brantlew (Mar 19, 2007)

mfabel said:


> I just thought of a possible explanation - when you say I would need a second coax to my cable box, what do you mean by "cable box"? I was being loose in my terms, and assuming you meant my VIP722, but maybe you are referring to a distribution box you have somewhere in your house. If so, that would explain why you use the additional set of diplexers to avoid a new cable run. I do not have anything like that, so my current diplexer is right by the dish, and very close to where the antenna would go.


Sorry, I can see how "cable box" was a bad choice of words. I have a little plastic enclosure box installed by the cable company on the outside my house which serves as a distribution point where all my coax enters into my house. This is represented on the left side of the house in the diagram. There is about a 100 foot run of coax from the satellite dish on the roof of my house that snakes around my house to this distribution box. Instead of going through the trouble of dropping a second line, I just inserted a couple of diplexers so that I could utilize the existing satellite line to transport my antenna signal as well. Naturally, if it is convenient to drop a second line then by all means do so as it will simplify your network and improve your signals.


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## mfabel (Jan 3, 2008)

Cokeswigga said:


> Make it easy for us...... draw a diagram of your house... with exsiting cables, and the location of your TV's and set-top boxes


OK, I think I understand how to do this. Wirediagram[3] shows my current setup. Wirediagram[4] shows what I plan to do. I am thinking of getting a CM 4221 antenna and 7777 preamp. I live a little over 30 miles from the transmission towers, and others in the area have had good luck with this antenna/preamp combo. Does it look like a good plan?


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## brantlew (Mar 19, 2007)

mfabel said:


> OK, I think I understand how to do this. Wirediagram[3] shows my current setup. Wirediagram[4] shows what I plan to do. I am thinking of getting a CM 4221 antenna and 7777 preamp. I live a little over 30 miles from the transmission towers, and others in the area have had good luck with this antenna/preamp combo. Does it look like a good plan?


Yeah that looks like it will work fine. The preamp looks like overkill to me however, +26 gain is huge and overdriving the signal like that can be undesirable. It looks like to me you only have about -15 db loss in your wiring which at 30 miles is probably fine - especially since you will be using digital television signals which are inherently more tolerant. First check your signal directly from antenna to your TV2 to make sure your antenna works well in the attic. Then I would hook everything else without a preamp and see what happens. If you notice scrambling and drop outs on TV1, then you can experiment with amps. I suspect the most you would need would be about +10db which you can find for pretty cheap. There is a nice little amp at Home Depot (of all places) that is affordable and is adjustable from +10 to +26d. You could experiment with something like that.


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## mfabel (Jan 3, 2008)

brantlew said:


> Yeah that looks like it will work fine. The preamp looks like overkill to me however, +26 gain is huge and overdriving the signal like that can be undesirable. It looks like to me you only have about -15 db loss in your wiring which at 30 miles is probably fine - especially since you will be using digital television signals which are inherently more tolerant. First check your signal directly from antenna to your TV2 to make sure your antenna works well in the attic. Then I would hook everything else without a preamp and see what happens. If you notice scrambling and drop outs on TV1, then you can experiment with amps. I suspect the most you would need would be about +10db which you can find for pretty cheap. There is a nice little amp at Home Depot (of all places) that is affordable and is adjustable from +10 to +26d. You could experiment with something like that.


I have a buddy nearby who put up a 4221 with a Winegard AP-8275 preamp (+28db), and he does not have all of the splitters and diplexers (plus his in outside instead of in the attic), so I figured I'd probably need to do something similar. Also, while my diagrams do not show it, the easiest install would actually use about 150 ft of RG-6 in the walls from TV 2 back to the upper diplexer, which I think adds about -7.5 db in the UHF range, which along with your -15 db estimate brings me to -22.5 db. While I am only 33 miles from the towers, here in San Diego there are lots of hills between myself and the towers, and tvfool.com tells me I should expect a -97db signal with a "2edge" path. So I guess I am expecting to need the preamp, but I like your advice on the adjustable Home Depot preamp. I'll take a look there and see if my local store has it. If not, I am hoping Fry's has the CM-7777 so I can test it and return it if not needed or it does not help. I do not want to fork out $70 if not necessary.


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## brantlew (Mar 19, 2007)

Hey mfabel I just realized something after looking at your diagram again. The orientation that you use on the upstairs splitter is crucial. Splitters have a definite orientation. Signal will travel smoothly from input post to the 2 out posts and in the reverse direction, but not from output post to output post. The output posts are said to be highly isolated. So in your situation if you orient your splitter with the antenna signal entering the input post, then TV2 and HDTV will both receive clear antenna signals but the 622 distribution signal will be isolated from TV2. Likewise if you orient the splitter so that the input post faces the diplexer then you will get the distribution signal at TV2 but no antenna signal at TV2. If you don't really care about receiving OTA at TV2 then no big deal. If you do want to receive OTA at TV2 then you have two options:

1. Orient the splitter with the input post facing the diplexer and then boost the hell out of the signal at the preamp. If you pump the antenna signal high enough it may bleed over enough to get to TV2, but you could hurt other components.

2. Add two more splitters to form a circle of three splitters so that all three pathways are unimpeded.


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## mfabel (Jan 3, 2008)

I always wondered about the orientation of the splitters, so thanks for that. I do not card about OTA at TV2 at this point, so that makes it easy for now.


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## mfabel (Jan 3, 2008)

OK, I did some testing this evening. All I have is a little loop UHF antenna, but I went to Home Depot and picked up the amplifier. I added the splitter at the 722 and at TV2, and hooked up the amplifier and antenna. I am able to get similar signal strengths now through the splitters and diplexers as when I hooked the antenna straight to the 722. I do need the amplifier to get any signal at all, but it does not seem to make much difference if I set it to the lowest setting (10 db) or max setting (25 db). Not sure what that means. It may mean that the CM 7777 would be fine at 26 db. Or, with a better antenna, it may be too much. The Home Depot amp probably has more noise, so maybe the 7777 would work better. Or maybe something like the Winegard 8700 (19 db). Any thoughts would be appreciated. I will go to Fry's this weekend and see if they have he CM 4221 and try it in the bedroom with the Home Depot amp before I install it in the attic. Maybe that will give me a better idea of what type of preamp I need.

I did see a new issue. TV2 had a poor quality picture (looked like interference in the signal) on ch 73 once I hooked up the splitters and antenna. I tried a higher channel, but that was much worse. So I changed from a cable channel to an OTA channel (ch 25), and it looks much better. Any advice on how to choose the best channel and not interfere with my OTA signals? I've looked at tvfool.com to see what my broadcast channels are, but I do not understand the difference between Real and Virtual channel, or the Channel vs. Frequency Assignment on antennaweb.org. Do I just avoid the frequency assignments of local stations listed on antennaweb? Do I need to have a gap of a few channels between my TV2 channel and broadcast frequencies?


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## brantlew (Mar 19, 2007)

mfabel said:


> OK, I did some testing this evening. All I have is a little loop UHF antenna, but I went to Home Depot and picked up the amplifier. I added the splitter at the 722 and at TV2, and hooked up the amplifier and antenna. I am able to get similar signal strengths now through the splitters and diplexers as when I hooked the antenna straight to the 722. I do need the amplifier to get any signal at all, but it does not seem to make much difference if I set it to the lowest setting (10 db) or max setting (25 db). Not sure what that means. It may mean that the CM 7777 would be fine at 26 db. Or, with a better antenna, it may be too much. The Home Depot amp probably has more noise, so maybe the 7777 would work better. Or maybe something like the Winegard 8700 (19 db). Any thoughts would be appreciated. I will go to Fry's this weekend and see if they have he CM 4221 and try it in the bedroom with the Home Depot amp before I install it in the attic. Maybe that will give me a better idea of what type of preamp I need.
> 
> I did see a new issue. TV2 had a poor quality picture (looked like interference in the signal) on ch 73 once I hooked up the splitters and antenna. I tried a higher channel, but that was much worse. So I changed from a cable channel to an OTA channel (ch 25), and it looks much better. Any advice on how to choose the best channel and not interfere with my OTA signals? I've looked at tvfool.com to see what my broadcast channels are, but I do not understand the difference between Real and Virtual channel, or the Channel vs. Frequency Assignment on antennaweb.org. Do I just avoid the frequency assignments of local stations listed on antennaweb? Do I need to have a gap of a few channels between my TV2 channel and broadcast frequencies?


If you receive decent signal with a loop antenna and just a +10 boost, then I suspect that a quality antenna alone will be enough to push good signals.

My tips on channels selection -

- The lower the channel, the better the reception. Low frequencies travel much better through air and wire for pretty much the same reason that bass sound waves travel further than treble.

- Once you get your antenna hooked up to downstairs, connect it to your TV and flip through analog OTA channels. Look for channels with pure white noise. Try to find at least three white noise channels in a row and choose the middle channel. This will be your cleanest channel that you can distribute your TV2 broadcast on.


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## mfabel (Jan 3, 2008)

I picked up a CM 4221 at Fry's this weekend. I now get two additional stations, but need an amp to get anything. I also took back the Leviton amp and got a CM Spartan 3 amp since it has a low noise factor. I took the antenna box up into the attic to see how it would fit, and the height will just barely fit in the attic. Does it matter where I place the preamp with respect to the antenna? Can it be in front of the antenna, or should I place it off to the side or behind the antenna? Since the height barely fits, I will not use any additional mast. I could attach the preamp to the bottom of the antenna, but not sure if it should be that close.


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## brantlew (Mar 19, 2007)

mfabel said:


> I picked up a CM 4221 at Fry's this weekend. I now get two additional stations, but need an amp to get anything. I also took back the Leviton amp and got a CM Spartan 3 amp since it has a low noise factor. I took the antenna box up into the attic to see how it would fit, and the height will just barely fit in the attic. Does it matter where I place the preamp with respect to the antenna? Can it be in front of the antenna, or should I place it off to the side or behind the antenna? Since the height barely fits, I will not use any additional mast. I could attach the preamp to the bottom of the antenna, but not sure if it should be that close.


?? I'm don't really have much experience with electrical interference of radio signals. You will have to experiment I guess.


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