# Is there a Composite to ATSC OTA digital channel modulator?



## jorb

The reason I Ask is because I recently bought a dtv converter box (coupon eligible) and it does not have an analog pass through and only a atsc tuner and not ntsc tuner. (It can’t pick-up an analog signal.) 

I modulate my satellite receiver on channel 4 and combine with OTA. The TV I’m using is an old analog 13” and has no composite inputs, just RF. So when I hooked up the dtv converter box I can only tune to the digital OTA signals and not the analog channel 4 signal and don’t want to use an A/B switch. 

Does anyone know who makes a composite to atsc OTA digital channel modulator?


----------



## curt8403

jorb said:


> The reason I Ask is because I recently bought a dtv converter box (coupon eligible) and it does not have an analog pass through and only a atsc tuner and not ntsc tuner. (It can't pick-up an analog signal.)
> 
> I modulate my satellite receiver on channel 4 and combine with OTA. The TV I'm using is an old analog 13" and has no composite inputs, just RF. So when I hooked up the dtv converter box I can only tune to the digital OTA signals and not the analog channel 4 signal and don't want to use an A/B switch.
> 
> Does anyone know who makes a composite to atsc OTA digital channel modulator?


the whole point of the dtv converter is that Analog is going kaput in Feb 2009, try taking the output of that converter (it should be switchable between 3 and 4) and combine with the signal from directv (one on 3 one on 4)


----------



## jorb

curt8403 said:


> the whole point of the dtv converter is that Analog is going kaput in Feb 2009, try taking the output of that converter (it should be switchable between 3 and 4) and combine with the signal from directv (one on 3 one on 4)


I've combined once already where the reciever is located. I tried to combine again 
by the TV and it looks Terrible to close to channel 5.


----------



## harsh

jorb said:


> Does anyone know who makes a composite to atsc OTA digital channel modulator?


Nope. I think it unlikely that ATSC modulators will ever be practical at the consumer level. The digitizing of the analog SD signal into MPEG2 is not trivial. I would expect that going forward, signals will be transmitted over wired networks of something like CAT5.


----------



## curt8403

jorb said:


> I've combined once already where the reciever is located. I tried to combine again
> by the TV and it looks Terrible to close to channel 5.


try a video game modulator that has RCA inputs for one signal and RF for the other?


----------



## texasbrit

jorb said:


> I've combined once already where the reciever is located. I tried to combine again
> by the TV and it looks Terrible to close to channel 5.


I think you are getting confused between the analog and digital signals. Let's restate what was already posted. The DirecTV receiver will output on channel 3 or 4. The new digital tuner will output on channel 3 or 4. You have to take the DirecTV output on channel 3 (say), and combine it with the digital tuner output on channel 4 (say). These are the only two signals you will have on the cable to the TV. There will be no channel 5, or any other channel, on the cable to the TV. 
If you want to receive the analog channels between now and Feb 2009 (when they go away) on the same cable as the channel 3 (DirecTV) and channel 4(digital tuner) signals, you will have to move the DirecTV and digital tuner signals to some other channel where there is no signal, or high noise level. You do this by using a two-channel "agile modulator" such as the ones from Channel Plus. http://www.channelplus.com/product_detail.php?productId=38 
You look at all the channels on your analog TV and find two blocks three channels wide that have no signal or noise on the middle channel of the three (e.g. you find that channels 27 thru 29 are clear so you can use channel 28). Having found two suitable channels, you then connect to the Channel Plus box as follows.
You split your OTA signal and route one leg to the Channel Plus box antenna input. The other leg goes to the digital tuner.
You connect the yellow/red/white connections from your digital tuner to the Channel Plus box and set the box to convert the digital tuner output to your first "clear channel' (center of a block of three). let's say that is channel 28. 
You connect the yellow/red/white connections from your DirecTV box to the Channel Plus box and set the box to convert to the second "clear channel", let's say that is channel 56. Now all the outputs from the Channel Plus box will contain all the analog channels, with the digital tuner inserted as channel 28 and the DirecTV box inserted as channel 56. 
When analog goes away, you can remove the OTA signal from the Channel Plus box and the output will only have two analog channels on the cable, channels 28 and 56.
I use this approach to route the signals from the output of my two DVRs around the house so I can watch them in any room.


----------



## Tom Robertson

A cheaper solution might be to wait for a converter that does pass the OTA thru. The last count I saw, there are four models. The least expensive will be the Echostar TR-40, also to be sold under the Slingmedia brand. Alas, won't be available until June-ish, if I recall.

Cheers,
Tom


----------



## JLucPicard

Dude,

How much could it cost to just replace that 13" RF only TV? That's where I would start, but whatever seems to work for you.


----------



## texasbrit

Tom Robertson said:


> A cheaper solution might be to wait for a converter that does pass the OTA thru. The last count I saw, there are four models. The least expensive will be the Echostar TR-40, also to be sold under the Slingmedia brand. Alas, won't be available until June-ish, if I recall.
> 
> Cheers,
> Tom


Having passthru does not help with the "combining" issues. You still end up with three sets of signals - the analog feed, the channel 3 (say) output from the DirecTV box and the channel 4 (say) output from the digital tuner. The chances are that (a) because channel 3 and 4 are adjacent they will interfere with each other (b) that there is some channel on channel 3 or 4 OTA, even if it is distant and is only generating noise, or (c) that there is something on channel 5 OTA and the channel 4/5 signals interfere with each other. In most areas you would be VERY lucky to be able to take the OTA stream, plus a channel 3 output plus a channel 4 output, and combine them. It certainly would not work here in DFW, where we have OTA analog broadcasts on channels 4 and 5. Even using a straight combiner for the OTA stream and channel 3 gives a very poor channel 3 signal. Hence the need for the agile modulator.


----------



## jorb

texasbrit said:


> I think you are getting confused between the analog and digital signals. Let's restate what was already posted. The DirecTV receiver will output on channel 3 or 4. The new digital tuner will output on channel 3 or 4. You have to take the DirecTV output on channel 3 (say), and combine it with the digital tuner output on channel 4 (say). These are the only two signals you will have on the cable to the TV. There will be no channel 5, or any other channel, on the cable to the TV.
> If you want to receive the analog channels between now and Feb 2009 (when they go away) on the same cable as the channel 3 (DirecTV) and channel 4(digital tuner) signals, you will have to move the DirecTV and digital tuner signals to some other channel where there is no signal, or high noise level. You do this by using a two-channel "agile modulator" such as the ones from Channel Plus. http://www.channelplus.com/product_detail.php?productId=38
> You look at all the channels on your analog TV and find two blocks three channels wide that have no signal or noise on the middle channel of the three (e.g. you find that channels 27 thru 29 are clear so you can use channel 28). Having found two suitable channels, you then connect to the Channel Plus box as follows.
> You split your OTA signal and route one leg to the Channel Plus box antenna input. The other leg goes to the digital tuner.
> You connect the yellow/red/white connections from your digital tuner to the Channel Plus box and set the box to convert the digital tuner output to your first "clear channel' (center of a block of three). let's say that is channel 28.
> You connect the yellow/red/white connections from your DirecTV box to the Channel Plus box and set the box to convert to the second "clear channel", let's say that is channel 56. Now all the outputs from the Channel Plus box will contain all the analog channels, with the digital tuner inserted as channel 28 and the DirecTV box inserted as channel 56.
> When analog goes away, you can remove the OTA signal from the Channel Plus box and the output will only have two analog channels on the cable, channels 28 and 56.
> I use this approach to route the signals from the output of my two DVRs around the house so I can watch them in any room.


Thanks for the info. 
Are you controlling the dvrs from a distant room using an UHF remote or are you using the IR target, IR emitter an optional IR control feature built-into the channelplus modulator .


----------



## jorb

curt8403 said:


> try a video game modulator that has RCA inputs for one signal and RF for the other?


Using a video game modulator would be an option but that also reminds me of a device that Niles makes or at onetime made, it was an audio sensing A/B
switch. They used them with juke boxes, when the juke box started playing music, the B side of (which was playing TV audio) the A/B switch would sense voltage and then switch over to the A side. I wonder if someone makes
a RF AV sensing A/B switch.


----------



## texasbrit

jorb said:


> Thanks for the info.
> Are you controlling the dvrs from a distant room using an UHF remote or are you using the IR target, IR emitter an optional IR control feature built-into the channelplus modulator .


I am using RF remotes....the ones I got with the DVRs were RF capable. Otherwise I would probably have used the IR target/emitter functions.


----------



## harsh

texasbrit said:


> Having passthru does not help with the "combining" issues.


Unless you're trying to do something stupid like combining cable and OTA, the OTA channels will take care of themselves. Buy a modulator that doesn't reside any where near a channel that you get OTA. They make modulators that are adjustable ("agile") that aren't too much more money.

Then again, as was suggested earlier, you could just ask around and see if someone will give you an TV that has multiple input possibilities. It is surprising how difficult it is to give away a TV these days.


----------

