722K OTA Signal Strength Differences

[dougmcbride]

I've noticed on my 722K there is usually a small difference (2 - 3 points) between the two OTA tuners on the same channel (bring up PIP and tune to the same OTA channel in each window, then SWAP to get signal strength) perhaps due to the splitting of the OTA signal inside the tuner module. I've got one channel that sometimes displays 10 - 12 points difference at some times, then goes back to the small difference at other times.

I've also noticed the signal strength meter in the OTA menu used to scan and enter/delete OTA channels many times will show a different signal level (higher) than either of the two tuners when watching video.

What have other 722K folks noticed on this if you've had a look?

Thanks,

Doug

 

[girdnerg]

I think there's a bug in the software for the signal meter myself. I get different readings depending on which tuner I'm on or if in the local channels menu.

 

[MikeD-C05]

I have always gotten different signal strengths on my ota tuners on my 722k. Sometimes I get 100 on both tuners using pip on the same ota channel on both tuners. Then the next time I get 100 and 88 on the other tuner using the same channel and pip. It doesn't cause any recording problems as all my signals are above 88 on all 4 major networks.

 

[whatchel1]

Thought this was know issue due to the way that they did the split inside the module being unusual.

 

[dougmcbride]

Thought this was know issue due to the way that they did the split inside the module being unusual.

Looks its more than that.

 

[highdefjeff]

I've noticed on my 722K there is usually a small difference (2 - 3 points) between the two OTA tuners on the same channel (bring up PIP and tune to the same OTA channel in each window, then SWAP to get signal strength) perhaps due to the splitting of the OTA signal inside the tuner module. I've got one channel that sometimes displays 10 - 12 points difference at some times, then goes back to the small difference at other times.

I've also noticed the signal strength meter in the OTA menu used to scan and enter/delete OTA channels many times will show a different signal level (higher) than either of the two tuners when watching video.

What have other 722K folks noticed on this if you've had a look?

Thanks,

Doug

The digital systems we are talking about here are considered to be fixed rate systems, but the truth is that there are many different bit rate requirements, depending on what you are watching.

When a signal is encoded for transmission the information is encoded with it's "high bit rate peaks" and "low bit rate valleys" of signal. For example, an SD cartoon needs relatively few bits/time, while a fast action HDTV sport scene needs the most. HDTV itself needs 5-6 times more signal/second than an SDTV picture. So to create the "fixed rate" illusion, empty filler, or padding, is added to the low volume/quantity information to 'fill' it to the equivalent of the highest bit rate needed in the stream. After padding, the bit stream resembles a fixed rate stream instead of a variable rate stream.

What I'm saying is that you will always see differences in signal strengths, not just because of the different lengths of the cables used, or the integrity of the connections, but the decoder actually has varying needs in regards to bit rate, depending on what is on TV.

 

[whatchel1]

Say what?

The digital systems we are talking about here are considered to be fixed rate systems, but the truth is that there are many different bit rate requirements, depending on what you are watching.

When a signal is encoded for transmission the information is encoded with it's "high bit rate peaks" and "low bit rate valleys" of signal. For example, an SD cartoon needs relatively few bits/time, while a fast action HDTV sport scene needs the most. HDTV itself needs 5-6 times more signal/second than an SDTV picture. So to create the "fixed rate" illusion, empty filler, or padding, is added to the low volume/quantity information to 'fill' it to the equivalent of the highest bit rate needed in the stream. After padding, the bit stream resembles a fixed rate stream instead of a variable rate stream.

What I'm saying is that you will always see differences in signal strengths, not just because of the different lengths of the cables used, or the integrity of the connections, but the decoder actually has varying needs in regards to bit rate, depending on what is on TV.

What does the bit rates have to do with signal strengths of the 2 tuners in the the OTA module. There has even been statements the SS is different between the 2 tuners when on the same channel. So how can there be differences in such a case. It is just the way that the 2 are split inside the module that makes the SS display differently between the 2 OTA tuners.

 

[KAB]

I finally got around to swapping tuners on my 722K. There is a 1-2 point drop on ONE VHF station (still in the mid 90s), otherwise, they are the same.

 

[dougmcbride]

I finally got around to swapping tuners on my 722K. There is a 1-2 point drop on ONE VHF station (still in the mid 90s), otherwise, they are the same.

Did you have an issue with the original module that caused the swap?

Doug

 

[KAB]

Did you have an issue with the original module that caused the swap?

Doug

We're not talking "physical" swap, rather tuner 1, tuner 2.