Diagnosing lip sync causes

KKlare

SatelliteGuys Pro
Nov 18, 2003
2,397
14
Los Alamos, NM
The rule is a nanosecond/foot in open air. The dielectric constant of the cable will make it slower by that factor. A foam coax typically has less high frequency attenuation than one with solid dielectric and it may have a lower DC attenuation because the center conductor will be relatively larger. All that can be negated by any small coax and you may do better with twisted pairs and baluns (balanced-unbalanced transformers) for very long runs.
-Ken
 

xterra

SatelliteGuys Pro
Jan 27, 2008
263
9
iceland
I think it's a dish Network problem. If it was your tv all the channels would be screwed up, but that's not the case For me, it only seems to happen when I'm watching FoxHD.
 

wetz73

SatelliteGuys Pro
Dec 7, 2007
605
0
Eureka, IL
The rule is a nanosecond/foot in open air. The dielectric constant of the cable will make it slower by that factor. A foam coax typically has less high frequency attenuation than one with solid dielectric and it may have a lower DC attenuation because the center conductor will be relatively larger. All that can be negated by any small coax and you may do better with twisted pairs and baluns (balanced-unbalanced transformers) for very long runs.
-Ken

You aren't going to run into too many wires with widely-varying dielectic constants. Let's say they have a value around 8, so that means you lose 8 nanoseconds per foot as opposed to in a vaccum. Still not enough to make you notice a lip sync issue. You'd probably need a dielectric constant around a million to notice it.
 

KKlare

SatelliteGuys Pro
Nov 18, 2003
2,397
14
Los Alamos, NM
You aren't going to run into too many wires with widely-varying dielectic constants. Let's say they have a value around 8, so that means you lose 8 nanoseconds per foot as opposed to in a vaccum. Still not enough to make you notice a lip sync issue. You'd probably need a dielectric constant around a million to notice it.
Yes, and dielectric constants (epsilon) are more than 1 and generally less than 2, except maybe diamond, or effectively much higher in an electrolytic capacitor. (I forget, but I think you may use the square root, too.) Also with spiral fill or foam the effective epsilon is lower--closer to 1. Too much on that, sorry.
-Ken
 

CubsWin

SatelliteGuys Pro
Lifetime Supporter
Dec 17, 2005
1,028
244
Bourbonnais, IL
Here's another idea:

Your sat receiver is probably set for 1080i output for your Hitachi. The Sharp is probably 720p native (right?). So, the Hitachi doesn't have to do any processing to the incoming signal, but the Sharp does.

Try setting the sat receiver's output to 720p and see if that makes any difference.

Brad
I tried changing to 720p and it didn't seem to make any difference. My Sharp Aquos is 1080p by the way, so it accepts the 1080i signal.
 

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