FEC Ratio and Dish size

[chapelrun]

I have a question about FEC Ratio and Dish size - - -

In general terms - - the closer to ONE the ratio is the bigger dish you need - correct?

For example - most 3/4 FEC stations I get fine with a 75cm dish but 5/6 FEC usually have trouble.

To even go deeper - - - other than asking - - - if a KU station is ITC and 5/6 FEC but you cannot fully tune it might it be something else like 4:2:2 or DVB-S2. Is there a way to tell or best guess this?

I currently have 3 dishes all KU band and the biggest is 1 meter. Come springtime I want to get into 4:2:2 and/or DVB-S2 but don't feel like I have read enough yet. Please point me to the required reading.

 

[Smith P.]

In general, yes using bigger dish will help you increase signal LEVEL, but there are other variable affecting packets corruption with high values of FEC: LNBF parameters - noise, cross-polarization, interference from adjusted sat, etc ...

 

[Mr Tony]

I have a question about FEC Ratio and Dish size - - -

In general terms - - the closer to ONE the ratio is the bigger dish you need - correct?

yes

For example - most 3/4 FEC stations I get fine with a 75cm dish but 5/6 FEC usually have trouble.

huh....I have no issues with anything on KU as long as it puts out enough power. Even Patient & Tip TV opn AMC3 which is 7/8 FEC I get fine on a 76cm dish

To even go deeper - - - other than asking - - - if a KU station is ITC and 5/6 FEC but you cannot fully tune it might it be something else like 4:2:2 or DVB-S2. Is there a way to tell or best guess this?

depends on what you mean by "cant tune it"...DVB-S2 you would know if it is or not because DVB-S2 you cant find on a blind scan. 4:2:2 the picture has tearing in it and you cant see it. weak signal (or not enough signal for a higher FEC) would be pixeling

I currently have 3 dishes all KU band and the biggest is 1 meter. Come springtime I want to get into 4:2:2 and/or DVB-S2 but don't feel like I have read enough yet. Please point me to the required reading.

4:2:2 and 4:2:0 work the same SD wise. My Quali-TV which can get both doesnt care if its 4:2:2 or 4:2:0, as long as there is enough signal to keep it stable. Unless I scan it in on the Coolsat 5000 which cannot see 4:2:2 (only the Q can see 4:2:2 from a set top box perspective) I wouldnt know the difference.

KU doesnt have many different FEC's. Most are 3/4 but on C-Band there are more examples. Example is on G16. The Networks are at 3/4 and I can keep them stable on a 6 foot dish with a 30 quality on the Pansat 1500. But the Equity mux on G3 which is 7/8 FEC I need at LEAST a 70 quality (preferably 75) to keep them stable.

Also some receivers handle the higher FEC different. The Coolsat 8000 keeps the Equity channels more stable than the Pansat does

 

[nelson61]

Gets even more complicated. For example, the new Ciel 2 satellite uses 2/3 with 8psk for everthing except the southeast where rain fade is a concern. In the southeast, they will use 5/6 but with qpsk. The 8psk is more susceptible to downlink problems. So, you have to look at more than just the FEC ratio .

 

[Smith P.]

Nelson61, Ciel-2 did not reach the 129W yet. And we didn't get real signals from it; and Dish changing FEC pretty often ( perhaps follow weather reports ?). Don't take recent NIT changes as real facts, especially talking about future setup - all Dish receivers use AUTO FEC mode; I've seen many times discrepancies between NIT and real FEC on Dish sats/tpns.

 

[chapelrun]

A few more questions

If DVB-S2 cannot be found with a blind scan - - how do you find them?

Does LyngSat list these as DVB-S2 ?? Do folks have another strategy to find DVB-S2 ?

Some stations found with a blind scan seem to want to display but have a "tearing" or "ripping" sound but no picture as Iceberg decribes earlier. These are most like 4:2:2 - - - correct? Would a PC card be the cheapest way get into 4:2:2 ?

 

[Mr Tony]

If DVB-S2 cannot be found with a blind scan - - how do you find them?

Does LyngSat list these as DVB-S2 ?? Do folks have another strategy to find DVB-S2 ?

Lyngsat lists them as DVB-S2...see AMC3 or AMC21. Folks use spectrum analyzers to find them

Some stations found with a blind scan seem to want to display but have a "tearing" or "ripping" sound but no picture as Iceberg decribes earlier. These are most like 4:2:2 - - - correct? Would a PC card be the cheapest way get into 4:2:2 ?

yeah a PC card would be the cheapest

 

[digiblur]

Nelson61, Ciel-2 did not reach the 129W yet. And we didn't get real signals from it; and Dish changing FEC pretty often ( perhaps follow weather reports ?). Don't take recent NIT changes as real facts, especially talking about future setup - all Dish receivers use AUTO FEC mode; I've seen many times discrepancies between NIT and real FEC on Dish sats/tpns.

The filings on the spotbeams stated the FEC and modulation for those beams.

 

[nelson61]

Nelson61, Ciel-2 did not reach the 129W yet. And we didn't get real signals from it; and Dish changing FEC pretty often ( perhaps follow weather reports ?). Don't take recent NIT changes as real facts, especially talking about future setup - all Dish receivers use AUTO FEC mode; I've seen many times discrepancies between NIT and real FEC on Dish sats/tpns.

I get my information from the FCC filings which specify exactly what they will do.

 

[Smith P.]

As I saw many times - Dish changing FEC constantly. I got my own solution - use Auto mode.

 

[digiblur]

As I saw many times - Dish changing FEC constantly. I got my own solution - use Auto mode.

I haven't seen them change the FEC except when E11 slid into place. They seem pretty constant on the FEC but I could be wrong as I don't really view much on their TP's, mainly just locking on for 10-15 seconds to see a few things.