Did you select antenna or OTA in set up?Also you might have to select ASTC in digital scan set up

you have the TV set up for Antenna input?

Are you sure that the TV does indeed have a ATSC tuner for receiving OTA? Just because it is an LCD TV it does not necessarily mean that it has the proper tuner. I've noticed that myself at CT especially in some of the lower priced products. If it does, then I would check the setup screen in the TV. Usually there is a spot to adjust the input signal from CATV to OTA. It seems odd that every TV you bring home would have this issue.

Many of the low end TV's do not include ATSC, and Canada doesn't really seem to care about mandating they do, unlike the US (and even if they have brought in a rule, AFAIK there isn't one against selling old stock that does not have a digital tuner).
Check the specs on manufacturer site/manual to ensure it does indeed have an ATSC tuner.

Although many low end TV don't have tuners, every TV (even the cheapest) from Futureshop that I've seen have one. They use an in-house RF feed - I believe it is ATSC actually, although I could be mistaken.

davemanson,
Did you read the operating instructions that came with the TV?
What does it say?

\/\/\/\/\/ - No point speculating when all the OP needs to do is read the owner's manual. It'll say what it's capable of as
well as explain what to do setting it up.

It's probably QAM - though QAM is almost always paired with ATSC, it may not be in all cases (haven't seen any, but who knows :p)

Thanks for all the replies!
Yup, the TV's definitely have ATSC tuners in them, I checked. They say NTSC/ATSC/QAM.
I also made sure the input was set to Antenna before scanning. The scans always reported no digital channels found and two analog channels found. It was the same for all 3 TV's I tried. I've kept the Toshiba (Toshiba 32" LCD HDTV 32C110U from Future Shop) and am using it with the set top box for now.

Hmmm! There's nothing more intriguing than a good mystery.

Sounds like possibly a cabling connector problem at the TV's input but you're not having the problem with the set-top box connection.What kind of set-top box is it?


Can you provide some antenna information?
What antenna are you using?
How high is that antenna?
Is your antenna surrounded by trees, buildings? [say,.. within 100ft?]
Is your location in a valley or on a hill or near water [river/lake] or in a densely treed area.

Do you have a preamp, a distribution amp or an amplified type of antenna?

How much cabling is there from the antenna to the TV connector?

I've had the set top box for a few years, I believe it's an RCA (not at the trailer right now to check).
The antenna is about 15 feet in the air and surrounded by trees. I'm about 50 feet from the Grand River.
There is about 30 feet of cabling. The antenna is just a regular old UHF/VHF antenna. I've had it for years.
No splitters or amplifiers are in use. It's just a straight run from the antenna to the back of the TV (or set top box).

Are the tuners in tv's different then the set top box? I find it strange it has no problem finding channels when the tv tuner finds none. It's the same cable.

Almost all tvs are set by default for cable tv .I bet the tvs are scanning for QAM not ASTC.

Did you set the channel tuning mode to digital or Auto.I beleive it comes set to standard which is for cable tv only.Dont forget to press done and enter when selecting anything

What's your TVfool report? Wondering if there is a station that's close to you, and is overloading the TV tuners? They could be more sensitive than the old tuner in your "RCA" box and more susceptible to overload.

Or maybe some other signal in the area is interfering with the TV tuners, since they are more sensitive. Someone operating a powerful HAM transmitter or something, or a cell tower?

When set to Auto, My LG TV scans in order,
"DTV" (Which is ATSC Over the air), then "TV" (which is Analog NTSC OTA),
Then "CATV" which is analog NTSC, but using the Cable Frequency Spectrum, some of which obviously overlaps analog OTA NTSC, and then lastly "CADTV", which is QAM. On mine I can interactively tell it which Mode to be scanning, Skip one or more, bail out of the scan process whenever I want, etc.

Of course all TV Manufacturers implement their SW / user interface differently, even within the same manufacturer exact steps may be quite different. But if your Convertor box is able to scan Digital OTA channels using the same coax feed as ur TV, but ur TV can't I would say the answer lies in what Make and model TV ur talking about. If we knew that much we could look online for a user manual, and possibly find an answer.

Thanks for all the help and advice!

Next time I'm at the trailer I'll give it another shot and see if I can figure it out and post back here with the results.
I'll be sure to get the exact model and specs as well.

I just bought a 2010 Vizio TV (M220VA) - fabulous, $168, 1080p, and gets a lot more stations than my $800 2007 Samsung PN42B450 (and better in almost any way that matters to a viewer, except square inches).

Can anything be done to heat-up the reception of the Samsung so it can get more/better those Buffalo stations the Vizio gets? Is the Samsung limited by S/N or by signal strength?

Thanks.
Ben

ATSC Tuners can have different performance due to several different factors:

1) Sensitivity - The older Samsung could be a couple or a few dB less sensitive.
NAB did a test on 6th Gen CECB's (so all same generation, many with the same parts)
showing only small differences, but older DTVs are probably less sensitive. Note that
loss of sensitivity did NOT correlate very well to the number of OTA stations missed:
http://www.nabfastroad.org/NABSTVDigitalConverterBoxEvaluation/DigitalConverter.asp

2) Multipath Tolerance - The older Samsung probably has difficulty handling
severe Multipath situations, which many times will require a higher S/N to overcome.

The Field Ensemble Test in ATSC A/74 specifically addresses this issue:
http://www.ntia.doc.gov/dtvcoupon/dtvmanufacturers.pdf
http://www.atsc.org/cms/index.php/standards/recommended-practices/180-a74-receiver-performance-guidelines?format=pdf

3) [B]Adjacent, Next-Adjacent & "Taboo" Channel Susceptibility - 6th Gen Tuners have
improved the ability to operate in the presence of stronger signals on nearby channels.
The FCC's OET group tested numerous 2005/2006 DTVs + STBs, finding significant
performance differences. We have NOT seen any recent retests, but WOULD expect to
still see differences among 6th Gen and later Tuners:
http://transition.fcc.gov/oet/info/documents/

4) Resistance to "Overload" - When you have multiple strong signals going into
a Tuner, InterModulation noise Distortion (IMD) WILL be generated...and sometimes
they will fall on top of weak signals. Different Tuners will behave differently.....

Which is why it is tricky to find the "optimum" balance of Antenna Gain, Downlead loss,
Distribution Gain and final Coax Feed loss which will allow operation with a
maximized Spurious Free Dynamic Range (Search: "SFDR"):
http://www.arl.army.mil/arlreports/2007/ARL-TR-4235.pdf [See Fig 3]
http://www.fiber-span.com/Application_Note_Spurious%20Free%20Dynamic%20Range.pdf
http://www.odyseus.nildram.co.uk/Systems_And_Devices_Files/Linearity.pdf

How can you improve the Samsung's reception (other than replacing it as you have done)???
You could try readjusting the SFDR "balance"....again....perhaps by inserting a variable RF
attenuator on it's input (only a few dB is needed, since each 1 dB causes 3 dB drop in IMD).
Feeding it with a separate antenna (no splitters) for sure will be an improvement.....

OK guy's, I finally had a chance to get back up to the trailer.
I was looking at the converter box and the TV trying to figure out what was different between the two and why one could find a bunch of channels and the other found none.
That's when I noticed something so obvious I had to smack my forehead!
The converter box has a little amp on the back that passes the signal from the antenna to the converter box. All this time I was taking the cable out of the amp and putting it into the TV then searching for channels, finding none of course.
This time I took the cable from the back of the converter box, leaving the little amp in place, hooked it up to the TV, did a scan and presto!! All kinds of channels start pouring in!
Such a simple mistake but easy to overlook I guess.
Thanks for all the help a suggestions guys!! Hopefully I can return the favor someday.

Sometimes those are actually coax power inserters for amplified antennas, whereas the actual amp is outside inside the antenna's case. If this was your case, you'd be disabling your antenna completely by not using it...

After trying several digital to analogue converters, i was convinced my small LG HDTV (2009) tv was the best performing in terms of reception sensitivity on my 2 nd edge channels, but recently i tested a Zinwell ZAT-970A converter, and it destroyed my LG on all the 2nd edge channels.

The Zinwell outperformed the LG, where the LG was not receiving channels, where weak channels were flaking out, and where channels were dropping out in bad weather. Some distant 2nd edge channels were locking at 3-20% signal quality on the Zinwell, where the LG didnt even register a "sniff". Im not sure if the LG tuner isnt as sensitive, or not as effective with multipath issues, or whatever.

So now I dont know what to do about the LG TV, should i be looking at a better HDTV, from what i had previously learned, the LG has one of the latest tuner designs, but obviously not effective enough given my situation.

The other option is keep using the Zinwell, or other comparable, and feed it to my LG HDTV (seems a waste of potential HD PQ though) ?