Does anyone know the level at which a typical HDTV will lock on the signal? By that I mean about what signal strength does it require for most TVs to allow it to be "seen" by the tuner.

I have a couple of stations that, according to TVfool, are at -54dBm...and a couple at -51dBm. I can catch the -51dBm but not the -54. Seems that's the threshold...but if I put an amp in line...I hope not to over drive the tuner on the "catchable" stations.

Trying to size the amp.

Does anyone know the level at which a typical HDTV will lock on the signal?

Hi there

I would expect that the tuner and the quality of the signal to determine that number. For a specific example (-49db okay, -51db no good) see this:
http://www.avsforum.com/avs-vb/showthread.php?t=1122271

Regards

Here is the tvfool.com report for your city. It would be more accurate if you went to tvfool and entered your exact address, which wouldn't show in the results:
http://www.tvfool.com/?option=com_wrapper&Itemid=29&q=id%3d507ce32a77af52

If you are in an RF shadow from a mountain for WAFF it might be necessary to specify antenna height and use the most exact coordinates that you can. Google maps gives coordinates from the link at the top right of the map. Your signal strength might not be what tvfool says.
And other than AntennaWeb...TVfool is the only site I use for that kind of stuff. That and the FCC antenna prop website...that I can't seem to find anymore...but then again I haven't looked real hard either.
Try this:
http://www.fcc.gov/mb/engineering/maps/

Which stations do you mean?

What is your antenna and where is it located? (still CM 4Bay up 20 ft ?)

With analog signals, signal strength is all-important. With digital signals, signal strength and signal quality (BER.....bit error rate/ratio) are equally important. It is possible to have a strong but poor quality signal.

You should be able to lock on signals in the range of -51 to -54 dBm.

The NAB-NSTV Converter Box Report says that the NTIA sensitivity spec is -83.0 dBm:
http://www.nabfastroad.org/NAB-STV%20Digital%20Converter%20Box%20Evaluation/Manuals-summary-report1.html
click on Digital Converter Box Report which should bring you to:
http://www.nabfastroad.org/NAB-STV%20Digital%20Converter%20Box%20Evaluation/Converter_Box_report.doc.pdf
Go to p21 in the pdf, 4 of 36 in the attachment

I made some tests with an Apex DT502 CECB, my signal level meter, and an attenuator. I didn't see dropout until about -88 dBm, but the signal did start to fall apart before that as shown by the loss of signal quality:
http://www.avsforum.com/avs-vb/showpost.php?p=15414426&postcount=8424

The digital tuner has an error correction system (FEC) that will correct a limited number of errors in the digital stream. Once that limit is reached, you will start to see tiles, picture freeze, and dropout at the "digital cliff." Signal quality is measured by BER. The factors that increase BER and reduce signal quality are:

1. Improper signal level: A weak signal will cause a poor signal-to-noise ratio; a signal that is too strong can overload a tuner or preamp. A nearby FM transmitter can also cause overload, which would require an FM trap.
2. Reflections from multipath problems, static or dynamic. Incorrect antenna aim or trees in front of the antenna can cause a mixture of direct and reflected/diffracted/refracted signal that is difficult for the tuner to process.
3. Impulse noise in the reception area (worse on VHF).

A signal-to-noise (SNR) of at least 15.5 to 16 dB is needed to maintain lock on a digital signal.

Trying to size the amp....but if I put an amp in line...I hope not to over drive the tuner on the "catchable" stations.
A preamp like the CM7777 might bring your strongest station near the overload point. How long is your coax downlead? You shouldn't need a preamp for the top 5 stations unless your coax is very long and you are splitting for many sets.

Going to fmfool.com shows that FM station WLRH on 89.3 is very strong.

Thanks Rabbit...and no, this is not for the Huntsville, AL area. I've got that stuff locked up. Yes WAFF has an RF shadow down the mountain where I live...but I still catch them.

This is for my mother who lives in SW Louisiana. Her ABC/CBS affiliates won't come in...both are either in Beaumont TX, or Lafayette La. The ABC affiliate is likely to deny her DNS channels from Direct TV. She can get the NBC Affiliate (KPLC) and the CBS (granted over Direct TV via DNS).....but I'm trying to size an amp for an omnidirectional "pancake" style antenna. I live up here in the H'ville area...and she lives 10 hours away...if I use a rotator, train her how to use it...and then it fails...I've got no way to fix it quickly...so I'm trying to not use a directional/multi-element antenna and use and amp....but I don't want to overdrive the tuner with a pre-amp mounted on the pole...but I have to be able to pull in the "fringe" stations.

It's a catch 22 type situation.

Oh, OK, I've got it now. I hope I gave you some useful ideas for your mother's location.
I live up here in the H'ville area...and she lives 10 hours away...if I use a rotator, train her how to use it...and then it fails...I've got no way to fix it quickly...
Very true; that makes good sense.

That would explain the -51 to -54 dBm signal levels which I couldn't find on your report! Still, it would be interesting to see her tvfool report.

zip code is 70665. Antenna Ht is 30 feet.
KBMT/KPLC/KFDM/KATC/KLFY are all some of the channels. Some are in Lafayette, La and some in Beaumont TX...KPLC is North of Lake Charles, LA.

She's in the Lake Charles DMA.

Thanks for the zip code; it should look like this:
http://www.tvfool.com/?option=com_wrapper&Itemid=29&q=id%3d507c0147eee677

Ah yes, there are some in the minus 50s. To answer your original question, I don't see any reason she can't get a signal of that strength, assuming she has the right antenna and no trees in the way. The last two will be harder because they are in the minus 70s and 1-edge. Your biggest problem, as you are aware, is that they are in different directions and on UHF and VHF-hi and you don't want to use a rotator.
Trying to size the amp.....I hope not to over drive the tuner
A CM7777 might bring KVHP near the overload point. Maybe a HDP-269 wouldn't, but still make up for coax loss.

I just stumbled onto this post. I live in 70665 and recently installed an antenna. I went with a large Winegard 7698. I am pointed east and am able to pickup KPLC (NBC), KVHP (FOX), KLFY (CBS), KATC (ABC), and PBS. The Beaumont stations are difficult for me to receive due to trees and a power transmission line to the west. A friend installed a Radio Shack pancake with an amplifier and is able to pick up these stations. PM me if you need more info. Glenn