Just bought a 32" LCD Toshiba and have been looking at the Signal Strength menu. I'm getting SNR (signal to noise ratio?) of 27.0 to 33.7 on 7 channels received, and signal power of 36.3 - 47.9. What do these numbers mean? There seems to be no relationship between SNR and Signal Strength - a low SNR can have a high Signal Power rating. I'm very impressed as the analog stations on an old Hitachi CRT came in rather snowy at times, but on this new TV I always get a great HDTV picture.

Thanks

Just bought a 32" LCD Toshiba and have been looking at the Signal Strength menu. I'm getting SNR (signal to noise ratio?) of 27.0 to 33.7 on 7 channels received, and signal power of 36.3 - 47.9. What do these numbers mean? There seems to be no relationship between SNR and Signal Strength - a low SNR can have a high Signal Power rating. I'm very impressed as the analog stations on an old Hitachi CRT came in rather snowy at times, but on this new TV I always get a great HDTV picture.

Thanks

I'll try to answer some of this. Maybe someone else can add to it. I have a Sony instead of a Toshiba and the display for this info is a bit different. SNR is Signal-to-Noise and its units are dB. In a perfect world you can decode an error free DTV signal at an SNR of 15.2 dB. In the real OTA world you probably need 16 dB. Your numbers of 27 to almost 34 dB are very good SNRs. I wish all mine were that good.

I'm not so sure what your Signal Power numbers mean. I'm going to assume they indicate real signal strength and not signal quality which is commonly shown on DTVs and does correspond to SNR. One possible reason why they don't correspond to SNR exactly is multipath (ghosting on an analog signal). It doesn't take much mutipath to drop the SNR a bit, especially at high SNR levels. You could have a relatively weak signal with no multipath and get a high SNR or a strong signal with much multipath and get a low SNR. Multipath sort of acts like adding noise to the signal.

Your 33.7 db SNR is probably about as high as anyone ever sees. The DTV transmitter has its own SNR, which from what I've read, typically runs in the low 30's. You can't get a higher SNR than what's being transmitted. You'll likely never see SNRs of 40+ dB even if the signal is very strong.

Thanks for the response Calaveras. I guess I should consider myself lucky. I have a CM 8 bowtie antenna and am pointing at 7 transmission towers located all on the same hill about 58 miles away, but, it means going thru alot of hills too.

What amazes me is that my 12 year old, analog, Hitachi CRT TV had snow alot of the times, so I thought that perhaps digital was out of the question. I think a couple of things are working in my favor, the preamp installed on the mast and a great tuner in the Toshiba TV.

Regards,
John