# DVB-S2X / DVB-S2 Minimum C/N Lock Calculator

#### cyberham

##### SatelliteGuys Master
Original poster
When I read on Rick's that ABC has started changing their modulation and coding formats, I was wondering how big a dish is needed to receive a DVB-S2X, a DVB-S2 or a DVB-S signal. These calculators will help figure that out by showing minimum C/N lock values required for many types of satellite signals you may receive. The short answer is a BIG dish is required.

DVB-S2X calculator: Click
DVB-S2 or DVB-S calculator: Click

For example, for a DVB-S2X, 16APSK, FEC 25/36, SR 34286 signal, minimum C/N lock value is just under 11 dB. These are the new specs for ABC.

When does that go into effect? I'm still picking up the feeds on 99W C-band with no problem. I'm getting 13.42 dB C/N on my osmio on a 12 footer (which needs to be repeaked when I stop being lazy).

FTA4PA
Sunday @ midnight ET. Your signal is plenty strong now to lock it.

comfortably_numb
When I read on Rick's that ABC has started changing their modulation and coding formats, I was wondering how big a dish is needed to receive a DVB-S2X, a DVB-S2 or a DVB-S signal. These calculators will help figure that out by showing minimum C/N lock values required for many types of satellite signals you may receive. The short answer is a BIG dish is required.

DVB-S2X calculator: Click
DVB-S2 or DVB-S calculator: Click

For example, for a DVB-S2X, 16APSK, FEC 25/36, SR 34286 signal, minimum C/N lock value is just under 11 dB. These are the new specs for ABC.
Since I'm not a math genius, can you clarify a bit what you mean by "a BIG dish"? Assuming I am in the continental US, would an 8 foot dish be big enough? 10 foot? 12 foot? Or some gargantuan dish that only a TV station or cable company would have?

It looks like they switched the feed on the 97°W satellite today; if that is actually the case and anyone is receiving the new modulation and getting a good signal can I ask what size dish you have and what equipment you are using?

Since I'm not a math genius, can you clarify a bit what you mean by "a BIG dish"? Assuming I am in the continental US, would an 8 foot dish be big enough? 10 foot? 12 foot? Or some gargantuan dish that only a TV station or cable company would have?

It looks like they switched the feed on the 97°W satellite today; if that is actually the case and anyone is receiving the new modulation and getting a good signal can I ask what size dish you have and what equipment you are using?
I just re-scanned 97W C-band and the ABC stations are gone. TVROSAT and Lyngesat doesn't show them. The 99W feeds are still present.

...Assuming I am in the continental US, would an 8 foot dish be big enough? 10 foot? 12 foot? Or some gargantuan dish that only a TV station or cable company would have?...
There's no single answer to your question. It depends. It depends on the parameters of the signal you are trying to receive. As the calculator shows, factors that affect your received signal include the DVB standard, type of modulation, the FEC value and the symbol rate. You need a big enough dish to receive at least the S/N specified by the calculator.

If doing a new install, and sourcing a new dish, I'd go for a 10-foot prime focus dish for C-band. For Ku-band, I'd personally install a 4-foot offset dish.

The ABC feeds are back on 97W but I can't seem to lock them. The osmio is suppose to receive H.265 does it not?

I've always wondered, how does one know what C/N they are seeing?
_
Neil

I just tried a rescan of 97W and now the ABC feeds are gone. They must be having problems?

I've always wondered, how does one know what C/N they are seeing?
You need a receiver that measures and reports signal quality in dB such as the Edision series. Many receivers report signal quality only using a % value.

The ABC feeds are back on 97W but I can't seem to lock them. The osmio is suppose to receive H.265 does it not?
I've read that the ABC feeds use 4.2.2 chroma subsampling. No consumer satellite receiver can receive this. Using an Edision, you need to feed the signal using its web interface into something like PotPlayer or VLC running on your PC. Then you can watch the video on your PC.

I rescanned 97W on my wifes dish and got all the ABC feeds at 14 dB. Hers is a 12 footer also. Apparently, the 12 footer that I use is way out of alignment.

I just used the DVB-S2 calculator to check out a current Ku signal on 99W. Parameters are:
DVB standard / modulation: DVB-S2 16APSK
FEC: 3/4
Symbol rate: 5000

Minimum C/N lock calculates as 10.2 dB. I am receiving 11.1 dB yet the received video is unstable and unwatchable. Normally an 11.1 dB signal would have been more than enough to receive good video. But not with 16APSK in this case.