Signal strength and quality question

[pollux]

On some FTA channels, you could have 90% signal strength and 0-10% signal quality, yet the video can be viewed flawlessly. for example, signal quality of the Ion-HD channels on AMC1 are low, but the HD can still be viewed. On the other hand, the DW channel has 90% signal strength, but when the signal quality drops below 65%, it starts to lose the image. Apparently there are other factors involved, what are they? TIA

 

[Magic Static]

On going discussion here http://www.satelliteguys.us/threads/331426-Signal-Strength-vs-Signal-Quality

 

[richyrich]

On some FTA channels, you could have 90% signal strength and 0-10% signal quality, yet the video can be viewed flawlessly. for example, signal quality of the Ion-HD channels on AMC1 are low, but the HD can still be viewed. On the other hand, the DW channel has 90% signal strength, but when the signal quality drops below 65%, it starts to lose the image. Apparently there are other factors involved, what are they? TIA

Mostly, channels being broadcast rely upon the "lobe" or bandwidth they have payed for; paying for what they really get. If they are looking for 999's there is perfect compared to others; environmental factors of any long term requirement usually hold keys to better equipment and "productions". Here, signal strengths and qualitys of each product purchased really make the cost factors soar; as does "the intended audience (language, continents, areas) shown. A basic way to say is every bit matters; and performance in all that matters is the broadcast specs; then spot on map and dish size dish install cable used receiver used meet in a final received "production"! Signal strength means lnbf dish combo in the direction it is aimed; plus cable loss (length). Quality means the numbers the receivers micro uses all at the same 60 hz needed makes a picture receivable at the end of the cable it is hooked to. If the margins in the micro mems receiver says good; it will show on the tv. Scan ok? Good! Every receiver show differences in strength and quality "numbers"; scanning what it can anyway it can; but only when the dish is correctly tuned to the satellite it wants; or has been programmed to scan. Each transponder it picks up is different in received power (strength) and an exact science in numeration (quality) also; which both depend on each being exactly perfect for each you want!

 

[danristheman]

Doesn't the FEC ratio play into effect in this question?

Dan Rose

 

[richyrich]

Yes, they are each, as a number used in the whole of things; the more errors; the more it must "correct" a very basic part of its "enumeration" which is problematic when something called noise makes errors; in the solution to the reception it makes a decision every 60th of a second: and is part of the decision a recvr finalizes every sixtyth of a second. Remember, if the dish is 20 percent off track; it adds 20 percent more noise to the signal as strength.

 

[Tron]

Basically, forward error correction (FEC) is the reason some transponders are lockable at low quality, while others require very high quality to lock. A 1/2 FEC will lock very low. A 5/6 needs decent quality to lock. A 7/8 needs very good quality and usually a large dish.

 

[pollux]

Basically, forward error correction (FEC) is the reason some transponders are lockable at low quality, while others require very high quality to lock. A 1/2 FEC will lock very low. A 5/6 needs decent quality to lock. A 7/8 needs very good quality and usually a large dish.

thanks, that make sense,
on AMC1 the ion-hd @ 4040H fec is 2/3; while DW @3740V fec is 7/8