tuners in new TVs

[John]

Is it really possible that the new HDTVs do not have tuners that are adequate? My story: I bought a Samsung LCD TV and attached it to my roof-top antenna. The set could not find a signal. With this very same antenna, I am receiving all the local stations quite well thru my converter box and analog TV. Perfect picture. A friend came over last night with a laptop that had a TV tuner device and he was able to find 42 stations by hooking to my antenna (some were not perfect, but far away). I'll admit that the antenna is old, but since I get nice reception with the converter box why does the brand new TV not work? Inquiries to Samsung, Best Buy, etc, all result in them telling me my antenna needs to be replaced or to get cable. The store that took back the set claims it was fine. I am hesitant to replace the antenna at this point - maybe a new one will not work either. Thanks.

[mtownsend]

It is possible for different receivers to have better or worse sensitivity ratings.

The two tuner specs that matter the most (if they are published at all) are its sensitivity and its noise figure. These will determine how well it deals with weak incoming signals. Unfortunately, tuner specs are rarely, if ever, published for your average consumer TV.

Did you add a splitter to test the TV? If you introduced a splitter that wasn't there before, the splitter itself will cause the signal levels to drop a bit (since the power is now being split to multiple paths). Also, some cables are more lossy than others (e.g., RG59 vs. RG6). In order to have an apples-to-apples comparison, you would need to make sure that each device is being tested against the exact same antenna feed (same cable, going back and forth between receivers) at around the same time of day.

In general, based on hands-on experience with several converter boxes and TV sets, I'd say that the converter boxes do tend to be slightly better than the built-in tuners of most TV sets, but the difference is usually small (maybe just a couple of dB). This should only affect weaker stations that are borderline receivable, so you should not observe that much difference on strong signals.



Another possible explanation for the differences you observed is multipath. Maybe your signals are strong enough, but the antenna is picking up signal reflections from somewhere (off of other buildings, hills, etc.). Some receiver chip-sets do a better job of coping with multipath than others using the "equalizer" logic in their design. Most newer chip-sets (built in the last 1-2 years) do a much better job than the ones from a few years ago.



Based on the information available, it's hard to say whether the problem was related to tuner sensitivity or its equalizer performance. If the problem is only related to the signal being too weak, this can probably be fixed by adding a pre-amp to your antenna setup (if you don't already have one).

If the problem is related to equalizer performance, then you might get very different results with a different make/model of TV that uses a different chip-set.



Generally speaking, there should not be anything seriously deficient in the design of tuners that are built-in to TV set. Maybe you got a lemon, maybe the particular make/model of TV had a bad (perhaps older) tuner design, or maybe the TV generates too much of its own interference (TV's have far more electronics internally than most converter boxes).

If you converter box and your friend's tuner dongle are able to pick up lots of channels cleanly, then I wouldn't expect that much of a difference using a TV's built-in tuner. If your antenna setup includes a pre-amp, I would expect almost no difference at all between the devices.

[John]

Thank you, Mtownsend. No splitter was in use, exactly same connection for new set and converter box. No nearby buildings or hills. Sounds like I should try another TV.

[mtownsend]

Do you have an amp on your current antenna setup?

[John]

No, but I was told by others that an amp only helps reduce line loss and could introduce noise into the system. I know my setup is not ideal (old directional antenna, old 300 amp flat wire from antenna into the house, then I connect to recently purchased good quality coax to go another 50 ft to the TV location. I can change out the old stuff, but was reluctant to consider that if it still would not make a new set work. Thanks again.

[ADTech]

I get several calls per week from folks who have a perfectly capable (newer) TV set that can't get any reception with a new antenna.

Most of the time, it is because they missed the requirement to switch the TV set from "CABLE" to "Antenna", "Air", "Broadcast", or "Off". Switching this menu item and rescanning usually gets them on the path to success.

FWIW, the tuners in new Samsung TV sets seem to perform well based on anecdotal feedback from our customers...

[Naomi]

The built-in tuner in my television (Haier) is definitely not as effective as my freestanding tuner (RCA) for anything, except viewing. The freestanding tuner can pick up more channels than my television's built-in tuner; I can check signal strength; and I can keep existing channels programmed when I do a re-scan. I cannot check signal strength, nor keep existing channels on a re-scan, with my television's built-in tuner. The television tuner does allow HD programs to show at the higher resolutions. I use the freestanding tuner to tweak my antennas for better reception, and view broadcasts through the television's built-in tuner.

Update 12-1-2010: I contacted Haier about the television set's built-in scanner. Haier's response: based on their belief that so few people do not have cable, or its like, there is little reason to have a better quality built-in tuner.

[Vanr]

I am very interested in this topic, My big problem is I have both weak & strong OTA signals, if I amp the weak ones my tuners overloads on the strong ones (unlike the analog days). I believe this should be a #1 priority in new designs of DTV tuners.

FYI...
I came across this article regarding the development and prediction of the future of the TV tuner industry.


http://www.edn.com/article/510511-Si...game_is_on.php

[Jason l]

So I'm Very interested in the same topic as I was geting channels on an old digital JVC tv that I couldn't get on a newer flatt screen generic brand.so when I bought my newest tv I questioned the salesman wich tv had the best ota tuner, he didn't have a clue, so I had him poll up info on the lgs and samsung. Samsung Had more intergraded recevers. Or somthing like that. I got a samsung and it is a little better than the generic one I replaced. However it does not have a channel guide like the free government recevers to convert digital to anolog tv. So I am going to bring a small bow tie antenna with me next time I buy a tv. To see wich is overall best for strength and channel guide. Samsung does have a channel guide with 2 showings now and after. Generic only has what is playing now. So any body have a tv with a good channel guide for ota ?

[Vanr]

1st I believe that OTA viewers are such a minority that the ability to tune in both weak & strong signals AND a have a nice user interface are not important to the TV manufacturer because it is very seldom used. Today most TV tuners are built with a chip (search google for “TV Tuner Chip Set”), these chips dictate the ability to bring in weaker signals and not be overloaded with strong signals, but as I mentioned I believe TV manufacturers are not interested in offering the best TV tuner on the market because almost no one cares.

I also recently purchased a Samsung smart TV, I found the guide to be as good as most of the DTV converter boxes, I believe (?) the TV matches channels in the guide to the channels that the tuner was capable of tuning in, in some of my DTV boxes the user can manually add channels if they know what frequency they are being transmitted on.
My problem with Samsung’s implementation of the guide is that my Samsung TV has to re-download the guide every ≈1.5 hours instead of downloading it only one time each day like all of my DTV converter boxes. If I’m watching a show and want to see what’s on next during the last few minutes of the current show I should be able to view the guide, but when I do this the current TV shows is frozen for 20 to 30 seconds while the guide is downloaded again, this results in missing something important at the end of the show I am watching.

I expect and welcome the day when TVs do not have a tuner built into them, this will result in a new market for tuner components (like a DTV converter box), maybe then the quality and feature set of the tuner will get better. Actually there are a few OTA tuner boxes on the market today, many of them allow you to record specific channels to a hard drive, some of them require a monthly subscription to get the guide.

[Jason l]

No more fees please. Lol Yess I agree most every one I know does not use there tv for OTA Chanel's. However it is the clearest picture compared to cable / dish / cheap receiverThat I have seen. Samsung does have a manual Chanel search.I can scan any frequency any time without changing what is already programmed. Witch is a lot of fun if you are a DYI 'er. It also pics up low and high signal good;as good as my old JVC digital tv and better than my genaric Emerson

[Stereocraig]

I wish they'd publish tuner specs, the way they do w/ quality audio components.

[Jason l]

Originally Posted by Jason l

No more fees please. Lol Yess I agree most every one I know does not use there tv for OTA Chanel's. However it is the clearest picture compared to cable / dish / cheap receiverThat I have seen. Samsung does have a manual Chanel search.I can scan any frequency any time without changing what is already programmed. Witch is a lot of fun if you are a DYI 'er. It also pics up low and high signal good;as good as my old JVC digital tv and better than my genaric Emerson

My mistake I have a toshiba not a samsung. any ony have a favorite tv for OTA signals?

[Jason l]

Originally Posted by Jason l

No more fees please. Lol Yess I agree most every one I know does not use there tv for OTA Chanel's. However it is the clearest picture compared to cable / dish / cheap receiverThat I have seen. Samsung does have a manual Chanel search.I can scan any frequency any time without changing what is already programmed. Witch is a lot of fun if you are a DYI 'er. It also pics up low and high signal good;as good as my old JVC digital tv and better than my genaric Emerson

My mistake I have a toshiba not a samsung. Anyone have a tv that works better for OTA signal? JVC and toshiba have done best for me.

[rabbit73]

The problem is, the tuners in TVs and boxes can vary a lot in sensitivity, and ability to handle multipath problems, from model to model. What I do, is to compare two tuners side-by-side by using a variable attenuator and a splitter to find out which tuner drops out last as I reduce the signal.

                                  tuner #1
                                 /
antenna > attenuator > splitter >
                                 \
                                  tuner #2

With my equipment, my SONY KDL22L5000 has about the same sensitivity as my Apex DT502 and Centronics ZAT502HD boxes. My later SONY KDL22BX320 is about 2 dB more sensitive.

[Stereocraig]

Originally Posted by rabbit73

The problem is, the tuners in TVs and boxes can vary a lot in sensitivity, and ability to handle multipath problems, from model to model. What I do, is to compare two tuners side-by-side by using a variable attenuator and a splitter to find out which tuner drops out last as I reduce the signal.

                                  tuner #1
                                 /
antenna > attenuator > splitter >
                                 \
                                  tuner #2

With my equipment, my SONY KDL22L5000 has about the same sensitivity as my Apex DT502 and Centronics ZAT502HD boxes. My later SONY KDL22BX320 is about 2 dB more sensitive.

My point, exactly!

Why should I shell out dough, to compare a TV's performance?

[tripelo]

Originally Posted by rabbit73

The problem is, the tuners in TVs and boxes can vary a lot in sensitivity, and ability to handle multipath problems

If using a preamplifier, the sensitivity of the tuner is not very critical. Sensitivity is mainly determined by the noise figure of the tuner. In most cases when using a typical preamp, the noise figure of the system approaches the noise figure of the preamplifier alone. Thus, the preamplifier is the main determinant of sensitivity.

One could take a poor sensitivity tuner and add a good preamplifier and probably exceed the sensitivity of the best available tuner alone.

Multipath is a serious concern, and not all tuners handle multipath equally. Better noise figure and S/N ratios can help multipath reception but only in a very incremental way.

The multipath capabilities of a tuner are determined by the demodulator chip (usually a system on a chip). In the 2009 generation of set top boxes there was appreciable variation in capability to handle multipath.

Presumably, the very latest generation demodulators have improved multipath capability. There is some evidence that suggests LG’s recent generation LGDT-3305 is improved with respect to multipath mitigation.

A way to compare receivers for multipath reception is to use a configuration similar to rabbit73’s, except to test:

- With a good preamp in line.
(To minimize effects of differing noise figures in the units under test)
- Against channels with known multipath problems.

As you know, there are several other factors that are important for a good tuner:

- Resistance to overload
- Selectivity
(ability to reject signals that are not specifically related to channel-of-interest)
- Others

Most critical factors were fairly standardized (probably due to NTIA set top box requirements). Noise figure and multipath capability are usually critical for fringe reception, with noise figure essentially controlled via the choice of preamplifier.

Originally Posted by Stereocraig

Why should I shell out dough, to compare a TV's performance?

You do have a point. But, having so far not seen much evidence of such tests:

It appears that manufacturers' do not have interest in publishing such helpful data. It also seems unlikely the current situation with technical specifications will improve.

With ATSC 3.0 well on the way, and almost certain to displace current ATSC (8VSB) with some form of OFDM, one might guess that R&D in the current ATSC will soon dry up.

If one wants the data/info, then someone has to pay the price and do the work.

.

[Stereocraig]

Agreed, Tripelo.

That's just not going to happen w/ common consumer grade products, like TVs.

The only thing most people care about, is screen size.

[ghz24]

I have two RCA converter boxes same model one is junk (10 channels missing 2 locals ) the other is a champ @ 24 channels ~9 dB better noise margin.
The silicon dust tuner I have seems really sensitive (didn't test at the same time as the two RCAs)

If using a preamplifier, the sensitivity of the tuner is not very critical. Sensitivity is mainly determined by the noise figure of the tuner. In most cases when using a typical preamp, the noise figure of the system approaches the noise figure of the preamplifier alone. Thus, the preamplifier is the main determinant of sensitivity.

One could take a poor sensitivity tuner and add a good preamplifier and probably exceed the sensitivity of the best available tuner alone.

I'm less than a mile from a transmitter and < 5 miles from 4 more.
I bought a very low noise floor quality pre-amp (it's on my shelf).
I intend on experimenting with it hooked to a very high gain antenna pointed away from the local towers.
I've been lead the believe the pre-amp will likely not be helpful with weak signals due to high signals from the locals.

I guess we should all get an indoor antenna, splitter and variable attenuator as rabbit73 suggests and haul it down to the store and insist on testing before the purchase.

[cindydale]

>>So I'm Very interested in the same topic as I was geting channels on an old digital JVC tv that I couldn't get on a newer flatt screen generic brand.so when I bought my newest tv I questioned the salesman wich tv had the best ota tuner, he didn't have a clue, so I had him poll up info on the lgs and samsung. Samsung Had more intergraded recevers. Or somthing like that. I got a samsung and it is a little better than the generic one I replaced.<<

I recently bought a Samsung Smart TV, and I'm not happy with the built-in OTA tuner. Does anyone have any recommendations either for technology to supplement the Samsung or a new TV?

Thank you!