Signal power versus signal quality

andrzej

Thread Starter
Board Certified User
Supporting Founder
Feb 18, 2004
690
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Boston subs
Does anybody know how signal quality is related to signal power? Initially, I thought that increasing signal power always increases the signal quality. However, I have seen reports with higher signal power than mine but with lower signal quality. So, for a given signal power, what determines signal quality? And which one (power or quality) is more important for signal reception and PQ? Any comments?
 

owlbox

SatelliteGuys Pro
Mar 18, 2004
223
0
MA
Good question

I currently have p=67-70, s/n=12.5, and q=85

I know the dish isn't installed right. It needs to be repositioned and repointed.
Anyway, I'm surprised that with the power as low as it is that the quality is 85+ Hopefully I can get someone in here soon to finish the install and get the signal up, even if I need to go to a 24" dish.
 

andrzej

Thread Starter
Board Certified User
Supporting Founder
Feb 18, 2004
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Boston subs
owlbox,
do you have any problems with sat reception? Your numbers are on the lower side, and I am wondering if you are having dropouts or not getting some channels at all?
 

fayrich

Old Fart
Lifetime Supporter
Mar 26, 2004
1,006
138
CLEVELAND, OHIO AREA
Call me stupid or whatever, but where is signal quality to be found? Have no problem finding the signal strength, but have been unable to find quality. Have looked at the hidden options 9-8-8 and 9-7-7 but do not see that info there.
 

Sean Mota

SatelliteGuys Master
Supporting Founder
Sep 8, 2003
19,039
1,738
New York City
FAYRICH said:
Call me stupid or whatever, but where is signal quality to be found? Have no problem finding the signal strength, but have been unable to find quality. Have looked at the hidden options 9-8-8 and 9-7-7 but do not see that info there.


It's in the same screen as strength. It is not in the hidden menu.
 

owlbox

SatelliteGuys Pro
Mar 18, 2004
223
0
MA
Andrzej,
If the weather is ok I have no problems. I've seen some dropouts etc. if the weather is raining etc. I have requested that the dish be remounted so the mount point is vertical and az/el can be correctly adjusted. While I'm at it I hope to change to a 24" dish. I'll pre-assemble the dish and when they go to move the 18"er it should be a no brainer to just use the 24"er in its place. Generally reception is good as is.
 

Sean Mota

SatelliteGuys Master
Supporting Founder
Sep 8, 2003
19,039
1,738
New York City
FAYRICH said:
Not on my box. At least not under "tune satellite signal". Is there a different approach?

VOOM button ---> Green Button---> system settings---> #7 ----> scroll down till you get to system status channel.
 

fayrich

Old Fart
Lifetime Supporter
Mar 26, 2004
1,006
138
CLEVELAND, OHIO AREA
Duhh----Thanks Sean. Really sorry to see your declaration a short time ago. Hope maybe you will reconsider. Wouldn't be the same without you.
 

andrzej

Thread Starter
Board Certified User
Supporting Founder
Feb 18, 2004
690
0
Boston subs
owlbox said:
Andrzej,
If the weather is ok I have no problems. I've seen some dropouts etc. if the weather is raining etc. I have requested that the dish be remounted so the mount point is vertical and az/el can be correctly adjusted. While I'm at it I hope to change to a 24" dish. I'll pre-assemble the dish and when they go to move the 18"er it should be a no brainer to just use the 24"er in its place. Generally reception is good as is.

owlbox,
In my case, when the installer left, I discovered that my mount point is not vertical and therefore the az/el readings are not what they are supposed to be according to az/el calculator for my location. This is pain in the a**, because it makes the whole readjustment procedure more difficult. Eventually, I tuned my sat antenna with my wife watching the signal meter. Now my sat quality is around 95-96 which, I think, should be good enough. But, my power is only in the 73-75 range. I am not sure whether this is good enough to withstand heavy rain etc.

Anyway, make sure that your new 24"er is mounted perfectly vertically. It will make the az/el readings meaningful and eventual adjustments so much easier.
 

cmslick3

SatelliteGuys Family
Apr 9, 2004
98
0
Chicago area
I think I may be able to help explain the signal strength / quality.

The signal strenght is the raw RF power received by the OTA receiver not taking into account any noise or errors.

The quality is the measure of the digital modulation that occurs to the RF channel. Basiclly this indicates lost/unusable bits, the more you lose the worse the quality, when too many are lost you get video/audio problems.

You can have great SS and poor SQ and still have a good picture, and vice/versa. If you live in an extremely noisy RF area you can have great signal but your local interference can hurt you as described below.

You need to look at is the C/I measurement this indicates the difference between the intelligent data on the channel and general RF noise. If this drops your quality will take a hit and you will begin to notice more audio/video issues. So you have 3 seperate items to deal with to get good picture, SQ which is dependant on SS and C/I cooperating with each other.

What would be nice to know is the measurement units and recommendations are for each measurement. Voom CSR's won't know this, you would have to get this information from an engineer..

I hope this helps and not confuses more.

Chris.. =)
 

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