What is the Data Rate for NASA at 119?

[jduffin]

I am testing a Wegener Unity 500 receiver that I just picked up and I am trying to receive NASA on 119W. This receiver requires that I enter in the Data Rate (DR) in Mbps rather than a Symbol Rate (SR). Can anyone tell me what a SR of 20.000 Msps translates to in terms of a Data Rate for this satellite?

Is there a formula or a reasonably easy way to translate between SR and DR?

Thanks and Merry Christmas!

 

[meinename]

Used this to figure it out. Don't know how accurate it is.
http://satelliteguys.us/thelist/fec.php

Assumed 20000 Symbol Rate and 7/8 FEC
Got 32.25 Mbps

EDIT: The title fetched was misleading...

 

[jduffin]

Thanks meinename! This has gotten me a step closer. It appears that the receiver is now locked on to the data stream -- but now I get a "NO MPEG" error.

I don't follow how you calculated the DR from the Satellite Angle application. I don't see any reference to data rates or symbol rates there.

 

[qwert1515]

The title says "Satellite Angle Calculator" because it was never meant to be released so it may not be user friendly.

Here is the DVB-S2 improved version of the calculator.
SatelliteGuys FEC Calculator 2

 

[meinename]

Thanks meinename! This has gotten me a step closer. It appears that the receiver is now locked on to the data stream -- but now I get a "NO MPEG" error.

I don't follow how you calculated the DR from the Satellite Angle application. I don't see any reference to data rates or symbol rates there.

I kinda have certain transponders memorized.

I'll refer you to lyngsat to fetch the important data or Symbol Rate and FEC for other transponders.

The FEC calculator requires a Symbol Rate and a Forward Error Correction to be selected.

NASA has a SR of 20.000 MSym per second or 20000 kSym
The FEC is 7/8
DVB-S QPSK modulation

As for the "NO MPEG", have you set the Audio and Video ID's? The PCR or such is usually the same as the Video ID as far as I know.
NASA is 4130 for the Video and 4131 for the Audio.
I don't know if they have to be in HEXidecimal for a Wegener receiver

I must defer to Qwert for the explanation on those formulas. Me too stupid (and lazy) to understand exactly how right now.

 

[qwert1515]

I must defer to Qwert for the explanation on those formulas.

The Formula is:

DataRate in Kbps = FEC * ((Symbol Rate) * (Reed Solomon Coding) * (Modulation Bits))

Example For DVB-S 20000 kSym/s 7/8 FEC:

DataRate = (7/8) * (20000 * 188/204 * 2))
DataRate = 32255 Kbps or 32.25 Mbps

 

[jduffin]

Qwert -- thanks for the formula. I have tried this on a few different linear satellites and have been successful in getting a picture using the Wegener receiver.

Meinename -- there isn't a place to enter VPIDs and APIDs on the Wegener receiver. You enter a "program number" instead. For NASA on 119W, this program number is 213. Even with entering this program number, I get the "No MPEG" error for this channel even though it is locked on to the carrier. I have been successful in receiving linear-polarized transponders on other satellites but I can't seem to get the DN FTA channels to work.

Is there anyone who has a Wegener receiver who is able to receive the DN FTA channels?

 

[meinename]

Qwert -- thanks for the formula. I have tried this on a few different linear satellites and have been successful in getting a picture using the Wegener receiver.

Meinename -- there isn't a place to enter VPIDs and APIDs on the Wegener receiver. You enter a "program number" instead. For NASA on 119W, this program number is 213. Even with entering this program number, I get the "No MPEG" error for this channel even though it is locked on to the carrier. I have been successful in receiving linear-polarized transponders on other satellites but I can't seem to get the DN FTA channels to work.

Is there anyone who has a Wegener receiver who is able to receive the DN FTA channels?

I've re-read the manual for the 500 and checked my notes. The "program ID" as Wegener calls it, is the station ID (SID) value. For NASA 213 is correct.

I'm stumped. Care to share what you set on the Carrier Select Screen?

I believe it should look like this:

                    From Table:      REQ
                    RF Feed          1
                    Carrier (MHz):   12370.75
                    Data Rate (Mbps) 32.255
                    FEC Inner Rate:  7/8
                    Tag Site:        15
                    Program #:       213
                    LNB LO (MHz)     11250
                    RF Polarization  “Vertical (14V)”

From Table means nothing to me right now.

Tag site affects the MPEG stream chosen but I don't understand how it does from reading the Unity 500 manual. Something that is set at the uplink, but North America is known for not using many things in the DVB-S standard. 15 is supposed to be special, as it says ignore the carrier name and just lock the Program number.

 

[jduffin]

Yes, my carrier setup screen has everything set the same as what you show -- and I still get the "No MPEG" error and a blank screen. I can confirm that the receiver is locked onto the downlink frequency.

One more data point -- I tried to get the History and Bio channels on 101W and got similar results. However, these channels would show briefly, pixelate and then the receiver would give the "No MPEG" error. These channels (as well as NASA on 119W) are received just fine on my Pansat 2500A receiver. On my Pansat, there are two sets of channels for Bio and History -- one with normal audio and one with AC3 encoded audio. I noticed the VPIDs are the same for each set of channels but the APID is different for the regular audio versus the AC3 audio channels. Since the Wegener doesn't allow VPIDs and APIDs to be entered, I wonder if it is getting confused with the regular audio and AC3 format of the audio. I would assume the hotels using these feeds would be using a receiver capable decrypting DCII signals. I wonder if these receivers have a program # identifier like the Wegener or if it would accept VPIDs and APIDs. I may have to do some more research on this...

The Wegener does work fine on a number of other channels that I have tried it on (ABC News feeds and BYU on 89W, 3ABN, BVN, and Sentana Sports on 101W, and the Caribbean Nets on my 1m mini-bud at 99W).

I too am stumped with this one. Maybe I need to start a new thread specifically on Wegener receivers....