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Stellar Labs ATSC HD Modulator

34K views 203 replies 23 participants last post by  JHBrandt 
#1 ·
Just curious if anyone out there has any experience with the new Stellar Labs ATSC HD Modulators being offered by MCM Electronics? It maxes out at 720p, and only offers HDMI input but for the price they look like they would meet the needs of most home users. I recently picked up one of the PVI Micromod's, but still would like to modulate some additional channels along with my antenna system. I'm seriously considering trying one of these, but was hoping somebody else had tried one already first to get some feedback?

http://www.mcmelectronics.com/product/33-11980
 
#2 · (Edited)
Lower cost ATSC Modulator for under $300??

This product accepts a high definition HDMI AV signal, and places that signal on a standard UHF television channel, to be transmitted
over standard 75 ohm cable including RG59/U and RG6/U, at distances up to several hundred feet. HDMI material from a computer,
DVD or Blu-Ray player, video game, HD video camera or similar source may be placed on any TV channel from CH14 through CH69.

That signal may be combined with existing RF signals from outdoor television antennas or other ATSC modulators, set to different channels.
Connections include HDMI input plus feedthrough output, and modulated RF output (female F) and loop through input. USB input is also provided
allowing the playing of media files from thumb drives and similar storage devices, over the modulated output.
The 'manual' is here;
http://www.mcmelectronics.com/content/ProductData/Manuals/33-11980.pdf

There is also a user review (that appears to be legit). It appears to work as a combiner with a RF input and output. Note the channel table goes past ch. 51, up as far as the older NTSC sprectrum of ch 69.

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Attachments

#4 ·
Sorry 'bout that, I didn't see that. :eek:


Additional details:

Simultaneous readout of UHF channel number and frequency
HDMI input with loop output
Female “F” connector RF output
Female “F” combined input
Output frequency range: 473 ~ 803MHz (6MHz steps)
Output channel range: CH14 ~ CH69
Output signal strength: +25dBmV
Accepts resolutions up to 1080p
Output resolution: 720p

Specifications (general)
Video input Single HDMI with loop output
Input resolution Auto detect up to 1080p/60Hz
USB input Plays AVI and MOV from flash memory
Encoding mode MPEG2
Audio format MPEG-I Layer 2
Dimensions 1-3/8” (H) x 9-1/2” (W) x 4-3/4” (D)
Power requirements 5VDC, 2A - AC adapter included

HDMI Input
HDMI version V1.3HDCP 1.2
Transmission speed 10.2Gbps (max)
TDMS 0.5 ~ 1.5V p-p
DDC 5V p-p (TTL)
HDMI cable limit Input
 
#8 ·
I own one of the earlier PVI HDMI/component to ATSC converters.
Cost me about $800.
It was a bad deal.
A few ads or change of resolutions and the audio quickly got out of sync with the video.
I quit trying to use it.
Now hopefully the newer models are much improved.
I have to assume they are, as the company is still in business. :)
 
#10 ·
I used the Stellar from MCM but ran into a few issues. The main issue is that the audio is glitchy on some tuners. Using my Channel Master DVR+, the audio stutters about twice per second. Using my Sony DHG-HDD500, the audio randomly drops out for a few seconds. Another issue is that it does not properly handle HDMI from my Roku SE player. It seems that the Roku produces RGB Limited (16-235), but the Stellar treats it as RGB Full (0-255), causing black to look brighter and white to look darker. I found a work-around that mostly solves it by putting a Siig CE-HM0031-S1 between the Roku and the Stellar. Lastly, the modulated output maxes out at 30 frames/second, so every other frame is dropped if the source is 60 frames/second.

I contacted PVI about the MiniMod and was told that there is no release date yet, even though some stores already list it. It looks very similar to the Lenkeng LKV379DVB-T, which is DVB-T (not ATSC) and lacks HDMI pass-through output (which the Stellar has).

http://www.lenkeng.net/Index/detail/id/181
 
#12 ·
Every Lenkeng product I've used(and I've used a few) has been iffy quality at best. And note they ALL have had black level issues like you so eloquently detailed. I was using my Lenkings to convert either HDMI or Component to composite/S-video so I blamed the black level issues on the fact that both HDMI and Component has a black level of 0-100 IRE while composite/S-video in N. America is +7.5-100 IRE and I just figured they were either designed for the rest of the world that used 0-100 IRE for both HD and SD resolutions or they just didn't take the IRE mismatch into account when converting the formats. Since this RF modulator uses HD and HD is 0-100 IRE worldwide it sounds more like design issues more than anything and personally unless you don't care about black levels I'd skip these devices.

Oh Eric, what is the " Siig CE-HM0031-S1" you spoke of? is it a PROC amp of sort or something specifically meant to correct black level issues?
 
#17 ·
Did you ever check to see if they have newer firmware? Don't bother searching their web site for it - you will come up empty. But tech support via email is not bad actually, and they might have newer firmware.
This is starting to sound familiar:
If you got the "new" STB3500II (recognizable by the channel 3/4 switch on the back), then it came with V2 and the newest version is V3. These firmware versions are not on iView's web site yet; you have to contact iView support and get them to email them to you.
 
#22 ·
That's too bad - but since it didn't work with the DVR+, it makes sense. I think so far, you're the only one here who's actually tried it!

I hope you give it a review on the MCM Electronics page. It sounds like the only big problem with it is the audio glitches; if they can fix that, this would be a nice way to record video from an HDMI output without a PC.

The failure with the DVR+ is disappointing, but I wonder if it would do better with an old DTVPal, or a cheap MStar box like a HomeWorX or iView. Those boxes also tune channels 52-69, which would solve any interference issues.
 
#24 ·
It sounds like the only big problem with it is the audio glitches; if they can fix that, this would be a nice way to record video from an HDMI output without a PC.
That's why I was curious about the GOP rate. Currently I have a TiVo and anything I record with it I can transfer over to my PC and burn to a Blu-Ray disc with minor adjustments. However none of the HDMI capture devices that record to PC produce recordings that work in this manner because their GOP rate is off. I'm hoping to use one of these to feed a DirecTV box into my TiVo as a modulated antenna channel. That way I can record and dump to disc or to my network hard drives. I think I'm going to gamble and try the PVI model first. The full resolution, and slightly higher price makes it worth giving it a shot vs the confirmed audio glitches with the Stellar Labs.

The signal is so strong that the DVR+ could receive it even when the modulator was physically disconnected. The antenna was located next to to the modulator, and the modulator's RF output was transmitting through the air to the antenna that was connected to the DVR+. When I moved the antenna farther from the modulator, it would lose the signal. Anyway, the audio glitches seemed to have nothing to do with signal strength or interference.
Wow... that is scary to me in itself. It must be putting off some major RF power for that to be the case.
 
#25 ·
I just ordered one of the Stellar Labs modulators. I have several tuners I'd like to try it out with. Once I've done that, I'll report back what I found.

BTW, MCM Electronics is running a Valentine's Day sale through Sunday: 14% off. I don't know if it will work more than once, but I was told to use offer code VTD702 at checkout.
 
#26 ·
Thanks for the heads up! That 14% off brought it down to a price point I was willing to take a gamble on. I ordered one as well, and likewise promise to report back what I find out. I'm going to ultimately need more than one modulator anyway so I can still try one of the PVI MiniMod's.
 
#32 ·
Erik Garci;
That's a completely different story. If that wasn't the case, that would of never passed FCC certification for RF emission testing. Anyway, I surely wouldn't feed that into a system before any DA's (distribution amps).
 
#36 ·
I got mine today as well but won't have a chance to play with it in depth until the weekend. Do some of the menu options only become available when you've fed a source into it? I see others here referencing audio settings. The only menu option I can get by playing with the front panel buttons is the option to set the channel.
 
#40 ·
I find no additional settings besides the menu option to set the channel. I will connect it to a device which will give me some flexibility to select audio output on the HDMI connector tomorrow/this weekend.

It shows the station name as Stellar and frustratingly since it sends time/date my TV clock changes when I change the channel to the device.

I will also hit it with a spectrum analyzer to see how clean the output is, although it would have to be fairly clean if it's expected to be mixed in with other signals on a wire and not interfere.
 
#44 ·
I'll check on the frame rate, it wouldn't surprise me if it is 30 fps. The audio issues may be related to the mpeg audio being utilized instead of AC-3. I am planning on using these multiplexed onto a house system RF feed. It ain't a cable quality modulator, but for the price it ain't bad. I have three set up on adjacent channels, and the receivers seem to lock with no problems.
 
#45 ·
I have three set up on adjacent channels, and the receivers seem to lock with no problems.
That's good news; it means they don't interfere with each other, at least as long as they're all roughly equally strong.

So if the top station in your area is RF 51, you'd need to skip up to RF 55 or so for the lowest one, but then you could use 56, 57, etc. all the way up to 69 without skipping any more channels.

Of course that would be super expensive, but at least you don't have to skip 3-4 channels for each additional modulator, so you don't end up with a fairly low limit of 4 to 6 channels above RF 51. (Of course there will be more free space after repacking.)

That may not apply if you mix modulators of different models though. It'll be interesting to see if the Stellar and PVI modulators can be used on adjacent channels.
 
#47 ·
The glitches do seem to come from the modulator. But oddly, not every receiver experiences them. So far we know the Channel Master DVR+ does experience audio glitches but some TVs don't. What receiver are you getting them with? Probably need to let MCM Electronics know, so if it can be fixed they can get Stellar Labs working on it.

No firmware update yet. Right now the MCM Electronics page only has a .pdf of the manual available for download.
 
#52 ·
I have three TVs, a westinghouse 32" circa 2008. This firmware was updated around 2010. This has no glitches.

A westinghouse 42" circa 2008 with factory original firmware (none available). This has audio glitches.

I also have one of the RCA DTV tuners from the original digital transition and haven't been able to get it to find the signal yet...

1/3 works

Really bummed. Had yuge hopes for this device.

Sources tried: Chromecast, Roku, and Popcorn Hour A100
 
#48 · (Edited)
Got mine last night and just now got a chance to hook it up and try it out. I'm using a DVR+ as input to the modulator for testing. Seems to work fine, even on "Channel Master TV" Internet channels.

Good news: no audio glitches on an old iView, although as previously noted, the time is stuck at midnight (precluding timed recordings on said iView). However, the HDMI source does need to be set to PCM; otherwise there's no audio at all. Apparently the modulator isn't smart enough to pass through Dolby Digital. Too bad - that would've been an easy workaround for the audio glitches.

Edit: I don't know if this is common or just an iView oddity (there are a lot of those), but my iView shows it as channel 16-4, not 16-1. I haven't been able to get Windows Media Center to recognize the signal on either 16-1 or 16-4 though, even though my PC's tuners see a strong signal on RF 16. As CPalmer2K suggests in the next post, there may be something funky about its channel map. I've had similar WMC problems with broadcast stations that don't have their channel map configured correctly.

I made a test recording of a minute or so of RT on the iView. It is indeed 720p30. According to MediaInfo it's true 30 f/s, not 29.97. Audio is MPEG version 1 layer 2, not Dolby Digital. Those oddities may explain why some receivers experience audio glitches.

More good news: When tuned to RF 16, I can receive KERA on RF 14 and KTVT on RF 19 just fine, so the signal doesn't seem to spread too far from the selected channel. Its high signal level does seem to overload the iView's tuner enough to interfere with most LPTVs in my area, even ones far from RF 16, so it looks like I'll need to attenuate its output.

HDMI pass-through seems to work fine. The only wrinkle is, when the HDMI input is turned off, a floating "no signal" banner is sent not only to the RF output, but also to the HDMI output! Not a big deal but something to be aware of.

That's all for now - more to come though.
 
#49 · (Edited)
It looks like this is going to be a return for me too. I've tried it with several sources, and get the same audio glitches others have described. Even more troubling to me is the fact that the audio/video seems WAY out of sync. Not to mention that the quality is much worse than the PVI mod I had used previously.

For testing purposes I've fed it several ways

First I tried feeding 1080i video thinking that because it is already 30fps it might eliminate some of the glitches. No dice using either "Dolby Digital" or "PCM". I did however get audio with Dolby Digital.

Next I tried feeding 720p with Dolby Digital and PCM. It actually seemed to function better in this mode, but it still has the awful audio glitches.

I think they need more of a *DELAY* on the input/output. I've seen some of the same issues on the older PVI modulator I had when I set the delay factor too low. I'd rather have the feed be delayed and be right than it be closer to real time with horrible sound.

Also the two TVs I have tried don't recognize the channel correctly. They see it is as 0-0
 
#50 · (Edited)
It looks like this is going to be a return for me too. I've tried it with several sources, and get the same audio glitches others have described. Even more troubling to me is the fact that the audio/video seems WAY out of sync.... I did however get audio with Dolby Digital.

...

Also the two TVs I have tried don't recognize the channel correctly.
So, glitchy audio with two different TVs ... What TVs were they? (If other readers have the same TVs they'll obviously need to avoid this modulator.)

Eric had better luck with his LG and Sony TVs. Hopefully it works with most/all of them. Edit: It does work with my LG TV, a model 32LK330-U8. I reset the modulator to RF 69; it came up as 69-4 on the LG. Here's a summary of what's been reported/found so far:


  • LG TVs: Works on some models (confirmed to work on model 55EC9300 and 32LK330-U8), not all
  • Panasonic TV: Works
  • Samsung TV: Works
  • Sony TV: Works (confirmed on model KDL-22BX300)
  • Visio TV: Works on some models, not all
  • Westinghouse TVs: Works on some models, not all
  • Dish DTVPal/Channel Master CM-7000Pal DVRs: Works, including recording*
  • Dish VIP722 (w/ ATSC tuner): Doesn't work
  • Channel Master DVR+: Doesn't work
  • MStar-based DVRs (iView, HomeWorX, etc.): Mostly works: tunes/plays channel OK; recordings are bad with some (older?) models but work with others
  • Philco CECB (probably Magnavox too): Works
  • RCA DTA800 CECB: Doesn't work
  • Windows Media Center: Doesn't work

*Found as channel 0-0, so the Pal assigns a channel number of 7n-0 (on mine it came up as 71-0)

Interesting you got audio (albeit glitchy) with DD pass-through while all I got was silence. Once I switched it to PCM, audio (on working devices listed above) was perfect: no glitches or sync issues.

At this point it looks like this modulator may work fine, or be totally unusable, depending on which receiver(s) you hook it to.

Edit: Sources I tried were a DVR+ and a Toshiba DVD recorder. Obviously quality on the Toshiba is limited to SD. The DVR+ was set to output 720p.
 
#54 ·
Just as an experiment I did reduce the signal heavily, wondering if overload might be causing some of the issues. I had a small bag of 12db attenuators I got several years ago to help bring my cable modem into spec (our neighborhood's signal is VERY high). I tried running the output into the TV first with one of those and then two of those, and finally three of them. I still had good signal at that point but the glitches were consistently the same.
 
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