Help ? sat sig pwr vs sig quality

[samiwax]

Thanks in advance if you can help me understand this readout on my system status menu.

Sat signal quality 97
OTA signal quality 96
Sat signal pwr/SNR 79/15.71
OTA signal pwr/SNR 68/28.56
Authorization status: SWO

Good numbers? Bad numbers? What would one expect to see here for good sys performance? Thnx Sami

 

[The Stone Man]

I'll try to explain. I have the document "Motorola DSR 550 Installation & Diagnostic Menu Guide", and in section 3.1, it has a bunch of mumbo jumbo about how the numbers are computed. It is pretty technical, and hard to understand. I can post that section if you want, but there is stuff in there that probably makes sense to engineers, but I'm baffled.

Generally speaking, your numbers are good. Keep in mind--the display that you posted correlates to ONLY the channel you were on when you went to check the system status. Signal quality is the same as signal strength. If your quality number is over 90, everything is wonderful. If it is 80-90, it's OK--but could probably be better by re-orienting the dish. If it is under 80, that's bad.

Weather can cause the signal quality to go below 80, and that will start to break up your picture. I've seen this happen, where the picture will pixelate and then freeze. It can drop the quality reading by 20 points when weather blocks the satellite signal from being received by your dish/LNB.

But rest assured, samiwax. The numbers you posted above are very good. If all channels are like that, you have great reception. And welcome to the forum!! Let me know if you want me to post the mumbo jumbo in that Motorola doc.

Here is a link to the Voom STB FAQ section of the forum. There is a lot of good info here: http://www.satelliteguys.us/showthread.php?t=13946

 

[Ricknau]

Stone Man,

I'd like to see the mumbo jumbo.

 

[The Stone Man]

OK Ricknau. Here it is. There is an explanation that the signal level number can be 0-99, with the following description:

"The signal level is a weighted average of the automatic gain control (AGC) and the signal to noise ratio (EsNo). Currently, the signal strength value is calculated as follows:

SS = (0.25 x AGC) + (0.75 x EsNo) where SS is signal strength.

AGC = (val + 50) x 2, for -70 <= val <= -20
AGC = -20, for val > -20; AGC = -70 for val < -70
val= value returned from Broadcom device's Power Meter function, truncated or rounded to nearest integer.

EsNo = 100 x (SNR - (threshold - offset)) / range where,

SNR = value returned from the Broadcom device's SNR function, truncated or rounded to the nearest 10th.
threshold = 7.3, for 1.92; 8.2, for 2.07; 8.7, for 2.11; 9.5, for 2.20; 10.2, for 2.30; 10.8, for 2.40
offset = 1.0, range = 10."

This comes from a Motorola technical document that was posted in the forum, but has since been taken away. While it was posted, I printed a copy, so I don't have an electronic copy.

 

[Ilya]

Keep in mind though, that the quoted document is almost a year old and the formulas (and the overall signal scale) have changed since then.