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RF Modulator for HDTV output?

post #1 of 49
12/30/07 at 1:27pm
Thread Starter 
This may be a silly question. But I havea JVC DH30000U HDTV VCR that has only two input forms: 1394, and an RF input for an antenna.

My cable box (TWC of San Diego) puts out 1394, DVI, and YCrCb. I've gotten the combo to mostly work by using 1394, and the VCR records fine if you simply hit the RECORD button on it. Playback is big and beautiful. But the VCR seems to not want to listen to the 1394 input if I use "timer recording" - it only gives you choices of various RF inputs when you use the timer.

Back in the good old days when there were only standrd (NTSC) signals, you could get an RF modulator that would take the NTSC signal and produce an RF signal, usually on channel 3 or 4, and feed it into the antenna input on your TV.

I know over-the-air HDTV signals exist, though I guess they're going to be phased out after a while. But that tells me that there are RF frequencies to be used, and an existing modulation scheme for HDTV RF signals.

Does anyone know of an HDTV RF modulator I can hang on the output (any output) of the cable box, that will produce a signal like the OTA HDTV signals, that I can feed into the antenna port on this HD VCR?
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post #2 of 49
12/30/07 at 1:33pm
No, it's just not as simple as it was with analog, you need hardware that can accept an uncompressed HD signal and recompress it in MPEG2 then transmit it via ATSC, it would take a few thousand in equipment to do what you want.
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post #3 of 49
1/2/08 at 4:16am
Quote:
Originally Posted by mjones73 View Post

No, it's just not as simple as it was with analog, you need hardware that can accept an uncompressed HD signal and recompress it in MPEG2 then transmit it via ATSC, it would take a few thousand in equipment to do what you want.

If the cablebox has a Firewire output, and the data rates are within 8VSB ATSC limits, then you could dispense with the MPEG2 encoding, as the Firewire output is an already encoded MPEG2 transport stream with compressed MPEG2 video and AC3 audio. You might need to remap the PIDs of the audio and video to make them ATSC compliant, and add some housekeeping data, but this isn't as complex as totally encoding. You would have to modulate to ATSC 8VSB still.

(ISTR that early Dish HD receivers had RF ATSC outputs, and were remapping DVB-S HD MPEG2 streams to 8VSB ATSC compliant streams without any decoding and recoding, allowing for an HD STB with no HD video processing)
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post #4 of 49
1/2/08 at 12:59pm
Quote:
Originally Posted by Little-Acorn View Post

I know over-the-air HDTV signals exist, though I guess they're going to be phased out after a while.

What?! No, they are not going to be phased out in the forseeable future.
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post #5 of 49
1/19/08 at 11:56am
I know this thread isn't that old, but is it still the belief that there are no economical(<$50) HDTV RF modulators available, nor will there be in the near future?
Sneals2000's post sounded like it could be done, but I'm gonna guess that a person would have to make such a device, and it would not be readily available to purchase at least at a price I would be interested in paying.
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post #6 of 49
1/19/08 at 1:39pm
Quote:
Originally Posted by jjeff View Post

I know this thread isn't that old, but is it still the belief that there are no economical(<$50) HDTV RF modulators available, nor will there be in the near future?
Sneals2000's post sounded like it could be done, but I'm gonna guess that a person would have to make such a device, and it would not be readily available to purchase at least at a price I would be interested in paying.

The problem is, there's no market for it. Most current devices that input or output HD video have the appropriate connections for it. Modern HD boxes also have no trouble outputting to SD connections and devices.

The OP would be better off springing for an HD DVR from his provider, then dubbing down anything he wants to archive later via firewire. He's just have to be sure the box he gets supports it.

The other option would be a new component input card for computers that was just shown at CES. With that setup, you could edit out commericials and excess video on each end of a program, then output to the deck via firewire.

Either of those options is obviously a tough workaround, but I don't see any other real options if the deck won't do a timer record over firewire.

I don't foresee anyone supporting HD to RF converters at this point - especially when it mainly would benefit an essentially dead video format.
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post #7 of 49
1/19/08 at 2:19pm
Actually my reason for the HD RF modulator would be to convert the HDMI or Composite output of a cable companies HD DVR to HD RF. Then receive the HD RF with a echostar TR-50 HD DVR, which has no inputs other than RF, and record it to removable HDD's.
I know it sounds like a convoluted path, but I don't know why the Echostar device is not providing a HD input other than RF. Of course all inputs would have to be CP complaint, I'm just talking about backing up non CP material.
I agree RF is kind of a dead format, as far as distributing the signal within a house, I never use the RF modulators in any of my video devices, but it's the best way for TV stations to get information to us.
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post #8 of 49
1/19/08 at 3:00pm
Quote:
Originally Posted by jjeff View Post

Actually my reason for the HD RF modulator would be to convert the HDMI or Composite output of a cable companies HD DVR to HD RF. Then receive the HD RF with a echostar TR-50 HD DVR, which has no inputs other than RF, and record it to removable HDD's.
I know it sounds like a convoluted path, but I don't know why the Echostar device is not providing a HD input other than RF. Of course all inputs would have to be CP complaint, I'm just talking about backing up non CP material.
I agree RF is kind of a dead format, as far as distributing the signal within a house, I never use the RF modulators in any of my video devices, but it's the best way for TV stations to get information to us.

That won't work. The Echostar unit is only designed to work with their signals. It won't tune anything else.
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post #9 of 49
1/19/08 at 6:58pm
Quote:
Originally Posted by NetworkTV View Post

That won't work. The Echostar unit is only designed to work with their signals. It won't tune anything else.

The Echostar TR50 is a OTA DVR, not a satellite receiver.
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post #10 of 49
1/19/08 at 7:33pm
Quote:
Originally Posted by madlobster View Post

The Echostar TR50 is a OTA DVR, not a satellite receiver.

I stand corrected.
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post #11 of 49
1/20/08 at 8:51am
I don't see why it wouldn't work, as long as the RF modulator would output to a OTA frequency, and not a QAM frequency. But my guess is the price of such a modulator would be prohibitive right now, if it will even get much cheaper, because as NetworkTV said, no one really uses RF to xmit signal this way anymore.
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post #12 of 49
1/21/08 at 9:09am
The real reason there are no digital RF modulators is because the studios do not want you to have them. A RF modualtor would generate an unencripted signal. The cable and satellite programming is such that they do not want you to have it unencripted so you can record it any way you want. People can tell you you do not need it but in reality they do not want you to have it.

BTW Little-Acorn, some with your setup use a programmable remote to tell the DVHS to record with a timer.

Rick R
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post #13 of 49
1/21/08 at 5:06pm
Anybody know when the TR50's will be available for sale?
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post #14 of 49
1/22/08 at 4:12am
According to the "official tr-50" I've been following, that's a no. No date or price yet. http://www.avsforum.com/avs-vb/showthread.php?t=972197
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post #15 of 49
1/22/08 at 6:27am
They do use an RF modulator - that being said, these things are still expensive and of little to no purpose for a home user. Perfect for CC or BB because they can hook up a lot of televisions to the same HD source without the hassle of trying to run component signals to all of them. (Which is what we used to do back in the "old" days of 1999

So many other ways to record/archive HD content these days, why would anybody bother making a "cheap" modulator? So somebody can record onto their HD VCR? Seriously, how big a market do you think there is for such a thing?
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post #16 of 49
1/22/08 at 9:55am
My two TV satellite HD DVR 622 outputs an SD analog modulated signal for the second TV that runs to the second TV. On a Technical Forum Dish was asked why they didn't output a modulated HD signal and the asnwer was because of the content.

Rick R
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post #17 of 49
1/22/08 at 10:13am
The setups that you see at Best Buy, Walmart, and other stores are an MPEG-2 player that outpus digitally to ATSC modulator. Instead of outputting a component or HDMI signal, the player outputs the straight MPEG-2 data (called a transport stream). The modulator takes the transport stream and adds a bit of data to make it conform to ATSC or QAM standards, and transmits it on the desired channel. The input could also be a professional satellite receiver (that's how digital cable works).

It's probably $5-10 thousand per store, depending on how they get receive the data. That would be a lot for home use, but when you have 50+ TV's to send signals to, it makes sense. Distribution equipment for component and HDMI is expensive and long cable runs are problematic. RF is a lot easier (especially since the wiring was probably already in place), and the setup of the TV's is simpler too. If desired, the signal could be easily combined with an OTA antenna.
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post #18 of 49
1/24/08 at 10:01am
I could see lots of reasons a homeowner would want a simple ATSC RF modulator. In a larger home, it could used be to fed by the output of a security video switcher.

An inexpensive way to feed a single DVR to multiple HDTVs, rather than use HDMI cables which cost hundreds of dollars.

I'm sure others could come up with other ideas.
Expensive or not, I too would like to know exactly what device the stores use for their demo.
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post #19 of 49
1/24/08 at 1:00pm
I would like to get a couple - right now, I'm using NTSC modulators to distribute DBS to all rooms in my house. When you can't get NTSC tuners anymore - it sure would be nice to be able to use ATSC modulators to do the same thing...
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post #20 of 49
1/24/08 at 1:08pm
Quote:
Originally Posted by flyin_frenchman View Post

I could see lots of reasons a homeowner would want a simple ATSC RF modulator. In a larger home, it could used be to fed by the output of a security video switcher.

An inexpensive way to feed a single DVR to multiple HDTVs, rather than use HDMI cables which cost hundreds of dollars.

I'm sure others could come up with other ideas.
Expensive or not, I too would like to know exactly what device the stores use for their demo.

If someone really has a large home or can afford the type of systems the stores use, cost of HDMI cables would probably not be an issue. Besides, with options like component over ethernet, there are plenty of alternatives out there for most current equipment.

I realize that stuff won't work for the OP, but the majority of viewers don't have that issue. Most DVRs have component either component or HDMI (or both) outputs now (and most TVs have at least one or the other), so that's where the majority of the available products will be geared.
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post #21 of 49
1/24/08 at 6:27pm
Quote:
Originally Posted by flyin_frenchman View Post

An inexpensive way to feed a single DVR to multiple HDTVs, rather than use HDMI cables which cost hundreds of dollars.

HDMI cables cost hundreds of dollars only if you insist on buying the hideously overpriced Monster Cable stuff. Try someplace like Monoprice instead.
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post #22 of 49
1/23/09 at 1:58pm
I have a house built with multiple RF cables crisscrossing all over the place nicely terminated at a patch panel. It would be rather difficult to replace them all with new HDMI cables because they run inside the wall, in the attic, and in the crawl space.

It would be nice to have a way of modulating HD video signals to RF so that any TV in any of the rooms can be reached.

Given the fact almost all digital TVs have a built in ATSC tuner,
to use a media center PC located centrally and for viewing those recorded programs this modulator would come in really handy.
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post #23 of 49
1/23/09 at 2:55pm
Make an offer to the liquidator at the CC store for the RF modulator. They are most likely going to wholesale off all the store equipment anyway and get almost nothing for them.
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post #24 of 49
1/23/09 at 4:53pm
Quote:
Originally Posted by Rick_R View Post

The real reason there are no digital RF modulators is because the studios do not want you to have them.

100% incorrect.

You can easily put together an ATSC RF system, but the difference is that you need an Analog to Digital encoder. Converting Analog to Analog RF was a cakewalk on comparision.

You need a HD Encoder to take the analog HD Format to Digital and those are very, VERY expensive.

After you have the signal in the digital realm, it is easy to convert it ATSC RF.

PC Cards that will do that end part have shown up on eBay in droves for $25 or less for years. 5 are currently offered at less than $20 each.

Just search for Item number: 190281966753
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post #25 of 49
1/23/09 at 9:08pm
We were looking for exactly what you all are talking about and never found it sort of!! This is what we did to distribute a HD computer 720p (1280x720) for digital signage in a new high school.

MAC mini computer VGA out to VGA to HDMI scalar / convertor (Atlona AT-HD500) (using VGA is required do to eliminate HDCP issues)

HDMI to HD-SDI (AJA-HA5) (HD-SDI is the broadcast HD standard connection)

HD-SDI in to HD Encoder by (Adtec Media Hub HD) (this also has composite and other inputs ect.) the output of this is a ASI transport stream.

ASI to QAM modulator (Blonder Tongue AQM with frame and power supply)

All of this hardware was about $15,000.00 Since this was installed in August of 2008 several new items (Blonder Tongue HDE-QAM) have been made but are still in the over $10,000 area!!

Still looking for a afordable solution SD box with Composite, Left, right audio in to SD ATSC digital out. This would be used for inserting channels on a home or apartment system.

KEN
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post #26 of 49
1/24/09 at 1:11pm
Quote:
Originally Posted by BeachComber View Post

Just search for Item number: 190281966753

Cool stuff, if we can get software to support it (not included in the auction).

tpctech, check it out. It's 8VSB, not QAM, but personally I'd prefer 8VSB anyway, since you can decode it with CECBs.

Quote:


You need a HD Encoder to take the analog HD Format to Digital and those are very, VERY expensive.

Generating the needed transport streams, even in HD, should not be a big deal at all.
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post #27 of 49
1/24/09 at 3:39pm
Quote:
Originally Posted by wmcbrine View Post

...check it out. It's 8VSB, not QAM, but personally I'd prefer 8VSB anyway, since you can decode it with CECBs.

The eBay page says it can be set to modulate to channels 14 to 21, but it doesn't say whether those are cable STD midband channels (120-168 MHz) or broadcast UHF channels (470-518 MHz). Only a few CECBs give the user the set-up option of selecting the cable STD channel plan, and I'd say that half or more of the ATSC capable TVs will not process an 8VSB signal if the TV has been set up for "cable" digital input, even if the 8VSB has been shifted to a cable STD channel frequency.

Quote:


Generating the needed transport streams, even in HD, should not be a big deal at all.

Famous last words. You can demodulate off-air 8VSB to what I believe is a usable stream using a readily available product from Blonder Tongue or Drake for under $2,000, and can then remodulate it to QAM for anther thousand or so (Drake has a modulator that puts two input channels onto one 6 MHz cable channel for about $2,300), but all other television programming has encryption in it that you cannot get rid of or work around.

I need to be able to modulate front door/lobby camera pictures to 8VSB format so I can continue to integrate them into the master antenna systems I service, but at present, I can't seem to do that any cheaper than the way that tpctech did it.
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post #28 of 49
1/24/09 at 4:22pm
Quote:
Originally Posted by AntAltMike View Post

The eBay page says it can be set to modulate to channels 14 to 21, but it doesn't say whether those are cable STD midband channels (120-168 MHz) or broadcast UHF channels (470-518 MHz). Only a few CECBs give the user the set-up option of selecting the cable STD channel plan, and I'd say that half or more of the ATSC capable TVs will not process an 8VSB signal if the TV has been set up for "cable" digital input, even if the 8VSB has been shifted to a cable STD channel frequency.

Famous last words. You can demodulate off-air 8VSB to what I believe is a usable stream using a readily available product from Blonder Tongue or Drake for under $2,000, and can then remodulate it to QAM for anther thousand or so (Drake has a modulator that puts two input channels onto one 6 MHz cable channel for about $2,300), but all other television programming has encryption in it that you cannot get rid of or work around.

I need to be able to modulate front door/lobby camera pictures to 8VSB format so I can continue to integrate them into the master antenna systems I service, but at present, I can't seem to do that any cheaper than the way that tpctech did it.


As i noted, the ebay unit is an ATSC unit, not a QAM modulator.

Quote:
Originally Posted by wmcbrine View Post

Cool stuff, if we can get software to support it (not included in the auction).

tpctech, check it out. It's 8VSB, not QAM, but personally I'd prefer 8VSB anyway, since you can decode it with CECBs.

Generating the needed transport streams, even in HD, should not be a big deal at all.

Its a bigger deal than you think....it has to be an absolute perfect 19.3 ATSC signal in real time or you will have issues.
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post #29 of 49
1/24/09 at 4:51pm
Quote:
Originally Posted by BeachComber View Post

As i noted, the ebay unit is an ATSC unit, not a QAM modulator...

I believe that ATSC is a data stream format that can be modulated in 8VSB or QAM RF, and the eBay unit modulates to 8VSB.
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post #30 of 49
1/24/09 at 6:08pm
Quote:
Originally Posted by Neil Griffin View Post

If desired, the signal could be easily combined with an OTA antenna.

This is exactly what our local BB does. They have an antenna on the roof that's combined with their in-house ATSC channel. It's nice to actually have real TV channels rather than just their glittery demo material.
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