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Old 18-May-2016, 12:13 AM   #1
user name
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Do _DIGITAL_ tv's have a problem with channel 2?

Watching over-the-air tv. Can pick-up channel 2(which broadcasts on channel 2) using large antenna and digital-to-analog converter and analog tv. Channel 2 is a strong(green) signal. When I attached the antenna to a new DIGITAL tv then scan, can not get channel 2 using new tv. What is wrong with the DIGITAL TV?
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Old 18-May-2016, 5:26 PM   #2
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Is the TV set in the off air mode, or perhaps it is in the cable mode instead. (Off air and cable modulation is not the same.)
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Old 20-May-2016, 12:07 AM   #3
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In the Phila., pa. area,

Channel 6 broadcasts at the end of the FM band
Channel 2 and 12 on the VHF band
The other channels on the UHF band

After scanning, channels 2 and 12 were _NOT_ detected!
Channel 6 was detected!

I did a second scan.
Channel 2 was not detected but channel 12 was.
But channel 12 is too weak to watch.

Channel 12 is a green channel and weaker than 2 according to the tvfool TV Signal Analysis.

Last edited by user name; 20-May-2016 at 4:57 PM.
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Old 20-May-2016, 12:57 PM   #4
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Sounds like the tuner in the new TV is not as good as the one in the A to D box.

TV's today are made for cable and sat, OTA tuning is not a priority for the manufactures anymore.
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Old 20-May-2016, 1:40 PM   #5
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TV's today are made for cable and sat, OTA tuning is not a priority for the manufactures anymore.
This has reached the point where Vizio, for example, has an extensive lineup of "Theater Display" models which don't even have antenna/cable tuners installed in them.
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Old 20-May-2016, 3:50 PM   #6
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Originally Posted by ADTech View Post
This has reached the point where Vizio, for example, has an extensive lineup of "Theater Display" models which don't even have antenna/cable tuners installed in them.
It seems like only yesterday, (Early 80s) that it was difficult finding a "Monitor only" for HT.
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Old 20-May-2016, 5:35 PM   #7
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Originally Posted by rickbb View Post
Sounds like the tuner in the new TV is not as good as the one in the A to D box.

TV's today are made for cable and sat, OTA tuning is not a priority for the manufactures anymore.
The DIGITAL tv is a Roku 5120x, TCL model 32S3750

The UHF channels were detected.
What percent of digital tv's have a weak vhf tuner?
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Old 20-May-2016, 6:53 PM   #8
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What percent of digital tv's have a weak vhf tuner?
Impossible to know, even if such a statement were actually true (which is doubtful). I've never seen anyone make such a claim before yours.

I have, however, heard of tuners so poorly made that they interfered with their own reception, particularly on VHF. I've also run across several customers who experienced interference from poorly made HDMI cables/ports and even one customer whose Google ChromeCast caused VHF interference.
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Old 20-May-2016, 10:15 PM   #9
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I heard that about 5% of the us population watches over the air tv.

Do tv tuners have a seperate vhf component?
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Old 20-May-2016, 10:54 PM   #10
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Quote:
Originally Posted by user name View Post
In the Phila., pa. area,

Channel 6 broadcasts at the end of the FM band
Channel 2 and 12 on the VHF band
The other channels on the UHF band

After scanning, channels 2 and 12 were _NOT_ detected!
Channel 6 was detected!

I did a second scan.
Channel 2 was not detected but channel 12 was.
But channel 12 is too weak to watch.

Channel 12 is a green channel and weaker than 2 according to the tvfool TV Signal Analysis.
You have made 16 posts and we still haven't seen your tvfool report. At least you finally told us Philadelphia PA so that we have a rough idea of what you are talking about.

The noise level on VHF-Low, real channels 2-6, is higher than on VHF-High. A much stronger signal is needed on 2 than on 12 to overcome the noise. The tvfool report does not take that into consideration. Channel 2 CBS in Chicago was such a problem they had to move up to channel 12.

It is not just how strong it is, but how strong it is in comparison to the noise level, which is mostly from electrical interference. The signal must be at least 15 dB stronger than the noise. This is calld SNR, or Signal to Noise Ratio.

Quote:
I heard that about 5% of the us population watches over the air tv.
I heard that it is more than twice that.
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Last edited by rabbit73; 20-May-2016 at 10:59 PM.
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Old 28-May-2016, 10:07 AM   #11
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attached is the channel file.

Attached is the channel file.
Attached Images
File Type: png digital channels only.png (74.5 KB, 229 views)
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Old 29-May-2016, 1:16 AM   #12
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Thanks for the image of your tvfool report. KJWP on real channel 2 seems very strong, and you are only 12.2 miles away.

Your tvfool report says Wallimhgord, PA; is that really Wallingford PA near the Nether Providence Township Police?

What is the model of the converter box?

What antenna are you using? Where is it located and how high is it?

How long is the coax line from the antenna to the TV?

Are you using a preamp?

Are there any trees or other buildings in the path of the signals from 48 degrees magnetic?

It does sound like the tuner in the TV isn't very good for VHF. It if really is that bad I would consider it defective. Can you return it for a refund or an exchange? Where did you buy it, Walmart?
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Last edited by rabbit73; 29-May-2016 at 2:43 AM.
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