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Discussion Starter · #1 ·
I am in the process of shopping for a Zenith SAT-520 or Sony HD-200 to replace my current Sony HD-100 because I am tired of the fan noise.


Threads that I have read on the SAT-520 seem to indicate that the unit has the capability to display the signal strength for OTA transmissions. However, I was in a store playing with the unit for about half an hour, and I could not find this feature in the sub-menus. However, I was able to locate the DirecTV signal strength meter.


If somebody out there could answer this silly question of how to get into the OTA signal strength meter for the Zenith or the Sony HD-200, that would be greatly appreciated.


Thanks,


Wayne
 

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Quote:
If somebody out there could answer this silly question of how to get into the OTA signal strength meter for the Zenith or the Sony HD-200, that would be greatly appreciated.
Just hit the "Signal" button on the remote of the HD200. You'll see the strength bar.
 

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I've been looking for a definitive answer about this and have yet to find anything discussing it, however I believe the signal strength meter for OTA digital broadcasts is actually created by displaying the amount of forward error correction that isn't being used. It's not that it's really a signal strength in the signal level sense.
 

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Thanks for the hint about the remote control. I went back to the store and it (obviously) worked. The reason that I was fixated on looking in the sub-menus is that's where it is with the Sony HD100.


Doug...you bring up an interesting point that you suspect it's not a true signal strength meter. My prime use for it is to help with rough pointing of my rooftop antenna. Hopefully it's good for at least that!



Wayne
 

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I'm not sure how they are calculating the signal strength for digital OTA, but it does work fine for pointing your antenna.


I had the wife watch the strength meter and flip between local digital OTA channels while I was on the roof and it worked like a charm. Got most of my signals from the 40-50% range up to 80-90% range by moving the antenna just 10 degrees or so.


Kevin
 

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I have the 420 and find the signal strength meter appears to produce similar results to the numeric calculation used by the DTC-100.


I don't believe it's discussing whether FEC is being used, instead I believe it has to do with the rate of errors. That's digital TV's proxy method for telling you how good or strong your signal is and explains why a better antenna direction yields a higher "signal strength."


Mark
 

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Originally posted by rogo
I have the 420 and find the signal strength meter appears to produce similar results to the numeric calculation used by the DTC-100.


I don't believe it's discussing whether FEC is being used, instead I believe it has to do with the rate of errors. That's digital TV's proxy method for telling you how good or strong your signal is and explains why a better antenna direction yields a higher "signal strength."


Mark
Mark, I'm not terribly well versed (yet :D) in the whole methodology of transmission of digital signals, but isn't that to some extent the same kind of thing? There's some sort of additional information transmitted that is used to correct errors. Redundant data, I guess, much like ECC information in RAM of some motherboards can be used to recover from single bit errors in a byte of RAM, though probably more complex than that. And as the decoder has to make use of that information to reconstruct the signal, it would be aware of doing so. I'd think that's about the only way it could determine any sort of "signal strength" display. At some point it can't reconstruct the signal because there's too many errors.


I'd also bet the "signal strength" is something calculated over some time domain which is why it slowly jumps around instead of being rather "instantaneous," which would account for times when the image is cutting out but the signal strength doesn't seem to match up; the errors being intermittent and causing problems, but since it recovers often enough it isn't fully reflected in the displayed signal strength.
 

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It sounded like the same thing to me, too.


On the other hand, a technician at Sonora Design said that in early Sony receivers, there is an internal analog potentiometer that can be screwdriver adjusted that will move the signal strength value up and down, so for that product, the signal strength number at least appear to be a weighted average of errors and actual strength.
 
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