S3 Tuner Sucks Eggs Is the Tivo HD Tuner Better?

[Free]

I have tried, for years now to get a digital signal OTA on my S3's, and have pretty much given up. The signal is weak, because of some large local mountains. However, I can lock in the stations on TV's, even a little 7" TV I have with a built in ATSC tuner.

With the S3, I can't get anything. Using the signal strength meter, I see a few channels with signals 50 and below. In order for the S3 to have a reliable picture, the signal must be 80 or above, even with cable channels, so the cable signal has to be perfect as well.

Are the tuners the same in the Tivo HD as the S3, and any possibility that a potential S4 machine would actually have a decent tuner in it?

[vstone]

Actually, when the S3 came out, its OTA tuners were as good as,and in some cases much better tham, other existing OTA digital receivers. I can't comment on how it fares relative to more recent receivers. The HD is essentially an S3 designed to cost much less, so I doubt they spent any money upgrading the tuner chip.

Due the many digital TV sets now being manufactured, the cost of digital tuner chips is probably way down now. I imagine an S4 would have a newer chip set, which would probably be at least a little bit betternthan the S3.

[pkscout]

Keep in mind that with both the cable and antenna input, the signal is split internally to two different tuners. That can often cause a signal loss of 2 or 3db. Borderline channels just won't survive that. Your TV has only one tuner, so it doesn't have to deal with the split. If you're bored, try adding a splitter to the line before you plug in into the TV and see what happens.

[berkshires]

One of the things "advertised" about the newer chips in the THD is superior tuning.

I have never had a chance to compare for myself, nor seen a comparison.

[bkdtv]

The ATSC tuner and demodulator in the TivoHD may be a little better than the original Series3, but I would not expect significant improvement. Most people seem to feel they are comparable, with perhaps a slight edge to the TivoHD.

The TivoHD was released in ~July, 2007 and its design was likely completed 6-12 months before that. ATSC tuners and demodulators have improved since then, so a "Series4" designed in 2008 would almost certainly feature improved reception.

If I may ask, have you tried upgrading/replacing your antenna? Members on the AVS forum and elsewhere have found a wide disparity in performance between different antennas. Here's an older roundup of antennas with test measurements (http://www.hdtvprimer.com/ANTENNAS/comparing.html). A fairly new roundup of indoor antennas with performance rankings can be found on AVS here (http://www.avsforum.com/avs-vb/showthread.php?t=1037779), and it also includes a few of the smaller outdoor models for reference purposes.

[Free]

Good thoughts and comments guy's I appreciate it.

I have several of the very best antenna's, and have been experimenting with them over the years. I am just blocked by a big mountain. I have also tried amplifiers, different types of cables etc. The best antenna I have found is the Antenna's Direct DB8.

I hope Tivo announces something at CES. I would really like to see a S4, that incorporated a better ATSC tuner, as well as a cable card-less solution. I am also hoping that, when the analog cut-off happens in February, there is a huge boost in the digital signal in my area??

[Adam1115]

I think the HD's tuner is better, but not significantly. i suspect you would have the same issue with the HD.

[bkdtv]

I hope Tivo announces something at CES. I would really like to see a S4, that incorporated a better ATSC tuner, as well as a cable card-less solution. I am also hoping that, when the analog cut-off happens in February, there is a huge boost in the digital signal in my area??That's a possibility. Have you checked the Local HDTV Info and Reception (http://www.avsforum.com/avs-vb/forumdisplay.php?f=45) thread for you area? Someone there would likely know about that.

[moyekj]

I hope Tivo announces something at CES. I would really like to see a S4, that incorporated a better ATSC tuner, as well as a cable card-less solution. CableCard free solution is highly unlikely. Even the newer cable boxes themselves are now mandated by FCC to use CableCards and there is no exception for tru2way solutions. If Tivo would properly support unencrypted QAM guide listings without CableCards that would make a lot of people in these forums happy.

[Free]

Good suggestion, just posted in that thread. I really only watch the 4 networks, so it really is a pain to go through all the Cox brain damage, to get them. I really would like to make OTA work.

[Free]

CableCard free solution is highly unlikely. Even the newer cable boxes themselves are now mandated by FCC to use CableCards and there is no exception for tru2way solutions.

This is troubling, since I have been told by Cox, they are trying to move away from CC support. I suppose, at some point they may just refuse to allow new Tivo installs, and mandate the 8300HD.

[bkdtv]

This is troubling, since I have been told by Cox, they are trying to move away from CC support. I suppose, at some point they may just refuse to allow new Tivo installs, and mandate the 8300HD.Federal law requires all cable systems with 750MHz (or more) bandwidth make CableCards available to all customers that request them. That is not going to change anytime soon. Note most Cox systems are 750+MHz.

True2Way devices use the same CableCards, but they add bidirectional receivers and what is essentially a JavaVM to run a downloadable Java version of the provider's STB software. Such True2Way boxes will support all cable services, including PPV, VOD, and SDV, with the cable company's interface. TiVo has said it is working on next-generation True2Way TiVo, which would retain their own UI for the guide and recording, with the company's interface for VOD.

In the next few years, Coax and others hope to move to downloadable DCAS, to download the encryption system directly into the box, but providers will still be required to make CableCards available for retail devices like TiVo.

[pdxsam]

I would also consider, since you can get the channel on the tv's but not the tivo, that the OTA tuner on the Tivo may be overloaded. I had the same situation you have with 2 tv's and the Tivo.. I went and purchased a variable attenuator at Radio Shack to see how much attenuation I needed, then put a fixed attenuator inline and haven't had a problem since.

When OTA tuners get overloaded they exhibit the same tendencies posted.

[pdxsam]

This is troubling, since I have been told by Cox, they are trying to move away from CC support. I suppose, at some point they may just refuse to allow new Tivo installs, and mandate the 8300HD.


I believe they would be in much hot water with the FCC. I thought that cable companies must supply cable cards to consumers who bring their own devices.

It's all part of the FCC trying to unbundle set top boxes from the cable companies.

[kb7oeb]

I would also consider, since you can get the channel on the tv's but not the tivo, that the OTA tuner on the Tivo may be overloaded. I had the same situation you have with 2 tv's and the Tivo.. I went and purchased a variable attenuator at Radio Shack to see how much attenuation I needed, then put a fixed attenuator inline and haven't had a problem since.

When OTA tuners get overloaded they exhibit the same tendencies posted.

In a related note if possible I would try connecting the antenna directly to the tivo without any amps or splitters in the line to get a base reading.

I have a low power digital local that my Tivo HD and S3 could not pick up reliably without amplification while my tv could. My amp has a gain control on it, and the tivo only needed a little amplification, if I turned the gain all the way up the station would break up.

[Free]

Thanks guy's, I do have an attenuator, and have tried connecting direct without amplification. With amplification, I can get some signal, but the weird part is it is from Tucson, which is South of Phoenix, and I am North of Phoenix. It is also not because Phoenix is too strong, because I am a long way from the transmitters, and the signal is weak. Just strange that I can get some stations from the city that is 100 miles on the other side of the one I want.

Still working on it though. I may try the new antenna and amp from Antenna's direct, to see how it works. (Clearstream 4).

[newskilz]

Getting a new antenna may be exactly what you need to do, since your current tv antenna may be old enough that it's not staying together well or what have you. Have you checked out AntennaWeb (http://www.antennaweb.org/aw/welcome.aspx) to see what type of requirements you have in order to pick up the stations you want? I don't see the Clearstream 4 you mentioned picking up stations all that far away, but I am not familiar with how well it pulls in the stations or what limitations you may have on antenna size.

At any rate, it hasn't really been mentioned before that I've seen, but a true tv antenna upgrade may be the answer to your problems for your TiVo OTA stations. Again check out the website and that should cover that area at least, then you can worry about your tuner itself. Hope this helps some at least.

[Free]

Well... I don't know what would be an upgrade to the DB8, since it is one of the best. I also have deep fringe antenna's from Winegard, and Channel Master, that never held a candle to the DB8. Lastly I have a 91XG as well, but the DB8 has picked up more stations.

The Clearstream, seems like a new design, that I haven't tried, and you are right, it is possible that my DB8 is a little battered from the elements over time. Anyway, I am going to keep trying.

[lrhorer]

Keep in mind that with both the cable and antenna input, the signal is split internally to two different tuners. That can often cause a signal loss of 2 or 3db.
'Not "2 or 3 dB". An ideal 2-way splitter with no additional losses whatsoever will lose 3.01 dB. In the real world, however, every connector has a certain loss and there is a certain amount of inefficiency in the internal components (turning part of the signal into heat). This inefficiency tends to be lower at lower frequencies and higher at high frequencies. A high quality splitter served by properly crimped high quality connectors will lose about 3.5 dB up to around channel 25. Up to around 500MHz, a high quality splitter will lose no more than 4 dB. Even a very good splitter may lose 5 dB or more at around 1000Mhz.

[lrhorer]

I am just blocked by a big mountain.
The very first CATV systems on the planet were developed for that very reason: It can be virtually impossible to locally overcome the effects of mountains or other opaque terrain blocking signal transmissions. CATV stands for Community Access TeleVision, and the first CATV systems were nothing more than a large antenna sitting on the top of a mountain with a steel cable running down into the valley. The tower collected the radiation on the mountain top and the steel cable passively radiated it on the pathway down the valley, increasing the signal level in the valley. Before long, the passive radiator was replaced by a coaxial cable and delivered directly to the eve of the house. Of course, it was also privatized so only contributors to the system would receive the benefits.

I have also tried amplifiers
If the signal level is too low at the outset, an amplifier isn't going to help. It will only make things worse, adding it's noise to the already high thermal noise. In order to be effective, an amplifier must be employed before the signal gets too low, not afterward. Generally speaking, an amplifier is used to overcome signal attenuation further down the line, not to make up for low signal levels. That said, in a low signal situation, the amplifier needs to be the very first thing after the antenna, with no more than a few inches of coax between the antenna output and the amplifier input. You also want the amplifier with the lowest noise figure you can get, not the highest gain.

I hope Tivo announces something at CES. I would really like to see a S4, that incorporated a better ATSC tuner, as well as a cable card-less solution.
Why would they do that? Almost no one would buy a TiVo without CableCards, excepting of course a satellite-based TiVo. Now a modular TiVo, allowing the user to swap out the CableCard module for a Satellite module would be great, but I doubt DirecTV would buy off on it. I have a notion they are going to lay heavy restrictions on the DirecTiVo hardware, perhaps even to the point of requiring TiVo to provide nothing but the software, while DirecTV supplies the hardware.

I am also hoping that, when the analog cut-off happens in February, there is a huge boost in the digital signal in my area??
'Not likely. Many, perhaps even most, stations are lowering their broadcast power with the DTV transition.

[lrhorer]

Well... I don't know what would be an upgrade to the DB8, since it is one of the best. I also have deep fringe antenna's from Winegard, and Channel Master, that never held a candle to the DB8. Lastly I have a 91XG as well, but the DB8 has picked up more stations.

The Clearstream, seems like a new design, that I haven't tried, and you are right, it is possible that my DB8 is a little battered from the elements over time. Anyway, I am going to keep trying.
'Not having looked over your shoulder, I can't be certain, but it sounds to me like you need to employ a little more engineering and a little less trial-and-error. The measure of a signal's quality is not its level, but the ratio of the signal level to the amount of noise. A "larger", "more powerful" antenna will increase the signal level, but if the noise also increases, one hasn't improved the situation. Noise comes from a number of sources, but the principle source of terrestrial noise is the temperature of the Earth. If the antenna is pointed skyward, then making the antenna more directional will increase the S/N ratio. Any antenna that points along the horizon is going to have very real limits to how well it can filter out terrestrial noise. If the signal is very point-like, then even a beam pointing toward the horizon can narrow its beam width with additional ground-plane elements, thus continuing to increase the S/N. In the case of a mountain blocking the signal, however, the source may not appear very point-like, and beyond a certain point a narrower beam width will reduce the signal along with the noise, resulting in no improvement in S/N. That's why mountains blocking the view to the transmitting antenna are a real problem. Certainly some antenna designs may be superior to others in this scenario, but there is a very real and solid limit to how effective any antenna can be in such a scenario. Note while many things can work to reduce the S/N of a signal, nothing - including an amplifier - can do anything to help a signal with a low S/N. Note also what constitutes a "better" antenna in most low-signal situations is not necessarily one which helps at all when there is a mountain in the way. The mountain not only attenuates the signal, it also disperses it, making it seem as if the signal comes from a nearby gigantically wide antenna (the mountain itself), rather than a point source far away.

Let me ask this: Who owns the mountain top? Might it be possible to get permission to set a passive radiator on top of the mountain? Do you have several neighbors who might be willing to pitch in? A mountain-top passive radiator antenna is not hideously expensive, but it is probably considerably more than one TiVo owner would be willing to pay.

[berkshires]

Note while many things can work to reduce the S/N of a signal, nothing - including an amplifier - can do anything to help a signal with a low S/N.

Has there ever been an attempt to use multiple antennas to pick up several versions of a poor S/N signal, put those through a processor using some type of error correction and come out with a result that is better than any one of the orignal attenna signals?

[Free]

I have not tried combining multiple antenna's, but have thought about it. I would need to find a tutorial on how to best do that, as I know it would be complex. I wanted to exhaust the simpler approach first.

I appreciate the analysis of the signal characteristics, and am attempting to do more engineering. I just purchased a Digair Pro, signal strength meter, which unfortunately arrived defective, but once I get a replacement, and figure out how to use it, hopefully it will help me to engineer a better solution.

Just a note on the mountain. It is about 1000 feet higher than my elevation, and the top of the mountain is a public preserve, so no way there is ever going to be an antenna up there. My best chance is getting signals that bend around, or bounce off of nearby hills etc. That may be why I am getting some Tucson channels over 100 miles away.

[txporter]

This is troubling, since I have been told by Cox, they are trying to move away from CC support. I suppose, at some point they may just refuse to allow new Tivo installs, and mandate the 8300HD.

I am pretty certain that the 8300HD actually uses a multi-stream card in it. The guys you speak to on the phone at the cable companies usually don't know what they are talking about in regard to CC. I wouldn't be too concerned with losing CC support.

Jason

[Free]

Ah, so the card is built into the box, that makes sense.

[pilotbob]

Federal law requires all cable systems with 750MHz (or more) bandwidth make CableCards available to all customers that request them. That is not going to change anytime soon. Note most Cox systems are 750+MHz.

Really. I was just talking to a local Brighthouse Networks rep via chat. I am thinking or dropping FiOS TV and going OTA. But, I saw the BHN $9.99 a month deal. It basically gives me the same channels an antenna would. However, the rep told me they would NOT rent cable cards to me if I had this plan and that I must go to the $52 a month digital package to rent cable cards.

I asked him if the FCC was ok with this, and he claimed they were.

Any contacts that I can talk to to get them to "reconsider"?

BOb

[kb7oeb]

I didn't realize you were near Phoenix, 3 (24) 5 (17) 45 (26) 61 (49) are using the permanent transmitters and as far as I know the only changes might be to move their antennas from the side to the top of their towers.

8, 10 and 12 are currently UHF but are moving back to their current analog VHF channels come 2/17. 15 is currently out of core on 56 and will be moving back to 15.

How is your analog reception? 8,10,12,15 analog might give you an idea for post transition reception. Are you seeing bad multipath? If you do have multipath I've heard some people are actually able to pick up a stronger signal from a reflection than they can by pointing directly at the station.

Take a look at this website http://www.tvfool.com/index.php?option=com_content&task=view&id=15 , you can download a file for google earth to see where the signal lands and see how much that mountain is messing you up. I always wondered why I could not see anything at all from Tucson when so many can and using this program I found a mountain a ways from my house casting about a 1 mile wide shadow.

[Free]

That web site is too cool, thanks!!!

I see now why I am getting something from Tucson, I didn't realize the direction the signals come from.

My Analog pretty much sucks as well, so I won't expect too much improvement from the transition.

[cramer]

I am pretty certain that the 8300HD actually uses a multi-stream card in it.
That would be an 8300HD-C or something like that. They aren't allowed to buy non-CC hardware, but they can continue to use the older, non-CC systems they owned prior to the integration ban. But from what I've seen, they have been phasing the integrated boxes out just to simplify setup.

And the card is not "built-in". There is a slot for a CC just like every other system on the market. However, it comes from the factory with a card already in it with a foil seal over it :-)

[cramer]

Now a modular TiVo, allowing the user to swap out the CableCard module for a Satellite module would be great, but I doubt DirecTV would buy off on it.
Nor would DISH. The issue is not receiving the signal, it's the conditional access system(s). Sat "TV" cards for PCs can see the signals for both DTV and DISH, but neither will authorize a smart card for them. (and DTV used to use a proprietary standard -- DSS.)

On the DTV front, they demo'd an HTPC thing last year that might, maybe, in the right universe, be usable by a tivo via USB. But I've not seen anything more about it since last year's CES.

[cramer]

Has there ever been an attempt to use multiple antennas to pick up several versions of a poor S/N signal...
A phased array? I don't think that'd work too well for terrestrial broadcasts. That would basically be a huge multipath signal to make sense of. Modern tuners go to great lengths to see through multipath signals and lock on to a single strong, coherent signal.

[Teeps]

Have you tried a bowtie antenna?

Here's a DIY: http://uhfhdtvantenna.blogspot.com/

Or manufactured.
http://www.summitsource.com/product_info.php?ref=1&products_id=4595

I'm about 70 miles from transmitters, I tried the Yagi type then found the bowtie antenna to work even better.

My S3 shares a 4 bay bowtie antenna with a MyHD MDP130 tuner card, pulls in all the locals with no problem, and it's in doors to boot...

You may need the 8 bay for your location.

[Free]

I think the DB8 is similar, but I have not tried that particular model.

[lrhorer]

Has there ever been an attempt to use multiple antennas to pick up several versions of a poor S/N signal, put those through a processor using some type of error correction and come out with a result that is better than any one of the orignal attenna signals?
Phased antenna arrays are quite common in the broadcast industry. They are used to eliminate terrestrial interference and multipath distortion by eliminating unwanted signals which interfere with the signal of interest. These signals are "unwanted" either because they come from a different source, or because there is more than one signal path from the desired source, and the secondary signal path(s) are longer than the primary path, resulting in one or more "ghost" signals arriving at the antenna. By carefully aligning the secondary elements of the array, inverting their output relative to the primary element, balancing their output, and adding all the signals together, the interfering signals are canceled by adding them to their inverse.

This won't help with a mountain in the way, however. The problem with the mountain is not multipath distortion nor secondary source interference. It's S/N. If we take two antennas with the same S/N and add their output together, then at best wnat we have is S + S + N + N, which equals 2S + 2N. Taking the ratio of the two components we get 2S / 2N = S/N, and we haven't gained anything.

I said it was a difficult issue.

[lrhorer]

A phased array? I don't think that'd work too well for terrestrial broadcasts. That would basically be a huge multipath signal to make sense of. Modern tuners go to great lengths to see through multipath signals and lock on to a single strong, coherent signal.

It works fine for terrestrial broadcasts, but it doesn't help much for a mountian in the way. They work great for situations where there is an interfering signal whose directionality is different from the primary signal, or where the S/N of the signal is good, but the signal is very low, as with astronomical sources. By definition, a phased array takes into account multipath artifacts and eliminates them. That's where the term "phased" originates.

[berkshires]

You guys understood exactly what I meant conceptually. Thanks.

lrhorer: Does that 2X argument hold true for digital where the data errors might be at different locations and perhaps several signals mixed together (each with data errors in different locations) might result in more good data?

P.S. how come the title of the thread wasn't "It Sucks Eggs to have a Big @$$ Mountain Between You and Your TV Stations?" :)

[pdxsam]

On the DTV front, they demo'd an HTPC thing last year that might, maybe, in the right universe, be usable by a tivo via USB. But I've not seen anything more about it since last year's CES.


I believe they pulled the plug on that project a month or so ago.

[Free]

P.S. how come the title of the thread wasn't "It Sucks Eggs to have a Big @$$ Mountain Between You and Your TV Stations?" :)

Ha, good point, if I could change the title now I would. :)

I see now that the biggest problem is my mountain, and it is rather amazing that I am able to get some channels from Tucson over 100 miles away.

[morac]

My S3 can tune OTA channels with fairly low signal strength (at least 60) while cable channels require signals of at least 85. What's more important though is SNR, not signal strength.

The main problem with the S3 is that because it has both cable and antenna inputs (which are not isolated), strong cable signals can knock out the antenna signals and vice-versa. I'm fairly close to Philly and when Comcast's signal quality drops (normally in the summer) I need to turn the amp on my antenna way down or I'll lose my cable channels.

[lrhorer]

The main problem with the S3 is that because it has both cable and antenna inputs (which are not isolated)
They most certainly are isolated. If not, dual inputs would never work at all. Nothing is perfect, however. Note also your isolation issues may not be inside the TiVo. Even a very tiny leak from your CATV system can knock out low signal level on your antenna, and any leak in the CATV sysem not only allows RF out, it also allows RF in. "RF Ingress", as it is known, has always been a major issue for CATV systems, to the point where local broadcast carrier channels are generally considered "impaired" frequencies. Most CATV systems avoid placing popular channels on any frequency where there is a strong local broadcast.

[lrhorer]

lrhorer: Does that 2X argument hold true for digital where the data errors might be at different locations and perhaps several signals mixed together (each with data errors in different locations) might result in more good data?
I'm not quite sure what you mean. Are you talking about taking two or more modulated signals, demodulating them, and then adding the outputs together? That usually won't work very well, for complex reasons having to do with the uniqueness of each demodulated signal, although something similar to this is done in analog video and in analog stereo audio transmissions. It's done not to decrease noise (it actually increases the noise), but to demultiplex unique components of the composite signal. In the case of stereo audio, L + R is added to L - R to obtain 2L and L - R is subtracted from L + R to obtain 2R, yielding unique Left and Right channels. In the case of analog NTSC video, the Cyan, Magenta, and Yellow components are derived by careful phase shifting of the incoming signals and adding the shifted results together to recover the unique color components.

[morac]

They most certainly are isolated. If not, dual inputs would never work at all. Nothing is perfect, however. Note also your isolation issues may not be inside the TiVo. Even a very tiny leak from your CATV system can knock out low signal level on your antenna, and any leak in the CATV sysem not only allows RF out, it also allows RF in. "RF Ingress", as it is known, has always been a major issue for CATV systems, to the point where local broadcast carrier channels are generally considered "impaired" frequencies. Most CATV systems avoid placing popular channels on any frequency where there is a strong local broadcast.

Based on what I saw I highly doubt that it's ingress in the cable lines. I have an amplified antenna hooked up to my S3 as well as coax cable. With certain cable and antenna channels tuned, if I slowly turn up the amp on the antenna, the DVR diagnostic screen will report the cable channel's signal strength dropping and eventually the signal will be lost. It's only certain combinations of cable and antenna channels so I can change the cable channel or antenna channel and the problem goes away.

Also tuner 0 is more susceptible to this than tuner 1 so things might works with OTA channel A on tuner 0 and cable channel B on tuner 1, but swap those and cable channel B goes out.

All of the above indicates leakage in the S3's tuners.


The weird thing about the issue is that the frequencies of the cable channels that get knocked out aren't even the same frequencies that the OTA channels are on. I suppose they could have been harmonic frequencies, but it's very strange.


In any case the way I have things set up currently I have my amp turned up just high enough to get the main channels. This degrades the cable channels slightly, but not enough to cause pixelation of drop outs (unless the cable signal weakens which it sometimes does in the summer). Unfortunately with this method I can't pick up some antenna channels that are a bit farther away, but they are also on my cable system so it's not a huge loss.

[berkshires]

I'm not quite sure what you mean. Are you talking about taking two or more modulated signals, demodulating them, and then adding the outputs together?

I am thinking about a box with 3 or more ant on it that converts the signal from each ant into digital data streams, and then a processor analyzes the 3+ streams and where there is disagreement at any point in the streams, makes a decision as to what the "correct" data should have been.