FIOS Signal Too Strong?

[nyt]

I have a new large screen plasma.  Is it possible to have too strong a signal that would cause the picture to look very grainy and show too much detail?  The TV's settings are calibrated properly.  How would you be able to tell what the optimum signal strength from the box is without having a tech meter it?

[KenAF]

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@nyt wrote:
I have a new large screen plasma.  Is it possible to have too strong a signal that would cause the picture to look very grainy and show too much detail?  The TV's settings are calibrated properly.  How would you be able to tell what the optimum signal strength from the box is without having a tech meter it?

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What plasma do you have?  And did you use settings suggested for your make/model over on the AVS Forum?

A problematic signal can cause stutter, picture breakup, and audio dropouts, but it will not affect grain or detail.

[DoctorJeff · Accepted solution]

It most certainly is possible! Mine was too strong. The problem is that Verizon just seems to assume that everyone has TVs in every rooms, with lots of splitters, so they pump a pretty strong signal out of the ONT. I have two splitters (-3.5 dB each) between the coax coming in my house and my TiVo. When I used the TiVo's signal measurement capability, it showed the signal pegged at 100%. I added a -6 dB attenuator (smarthome.com will sell you a bag of mixed values for $11), and that brought it under 100% at last (about 95%). So that's -13 dB of attentuation in total. Each 3 dB represents a doubling, so that indicates that the signal is over 16 times greater than it needs to be!

If your TV has a function to show signal strength, see if it's pegged at 100% (which probably means well over 100%). Saturating the inputs (even with AGC) like that isn't always a good thing. Get some attentuators and knock the signal down to just under 100% to make sure there's no saturation.

[nyt]

Great info, Dr. Jeff.  Thanks

[kevinb]

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@DoctorJeff wrote:

It most certainly is possible! Mine was too strong. The problem is that Verizon just seems to assume that everyone has TVs in every rooms, with lots of splitters, so they pump a pretty strong signal out of the ONT. I have two splitters (-3.5 dB each) between the coax coming in my house and my TiVo. When I used the TiVo's signal measurement capability, it showed the signal pegged at 100%. I added a -6 dB attenuator (smarthome.com will sell you a bag of mixed values for $11), and that brought it under 100% at last (about 95%). So that's -13 dB of attentuation in total. Each 3 dB represents a doubling, so that indicates that the signal is over 16 times greater than it needs to be!

If your TV has a function to show signal strength, see if it's pegged at 100% (which probably means well over 100%). Saturating the inputs (even with AGC) like that isn't always a good thing. Get some attentuators and knock the signal down to just under 100% to make sure there's no saturation.

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Unless you're using a STB at the TV, in which case the STB would be processing the RF and the TV would not see the signal strength at all. Unless it's referring to the strength of the signal between the STB and TV (HDMI signal strength?) which I don't know exists ..

[DoctorJeff]

Kevinb is absolutely correct. I don't use a STB, just the TiVo and (if both TiVo tuners are occupied and I want to watch something else) the TV's QAM tuner. So I completely forgot about the STB. If you don't have a TiVo, then you'd have to bypass the STB and run the cable into your TV (assuming it has a tuner) and then let your TV do an auto channel setup and then measure the signal. Or do the STBs have a signal strenght indicator?