Bandwidth 118 vs 129

[Pepper]

Was perusing www.lyngsat.com and www.dishchannelchart.com today. I notice that on both 118 and 129 the symbol rate for the transponders carrying HD locals (HDLIL) is 21500, FEC 2/3 and MPEG-4 compression.

For some reason, on 129 they are stuffing four HDLIL channels per transponder, on 118 only two. Thus on 118 each market of four HDLILs is taking two transponders.

Is Dish wasting space on 118, or are they providing much better PQ to the 118 markets than to the 129, or am I missing something else that would cause it to make sense? Maybe they are just keeping all the transponders on 118 active and will consolidate things when more channels are ready to be uplinked?

 

[JimK2]

21500 baud (symbol rate) on 118 is QPSK and 129 is 8PSK which can through put a higher imformation rate

21500-2/3 QPSK (2 bits per symbol = 42,000 Kbps times forward error correction = 27.9 Mbps
21500-2/3 8PSK (3 bits per symbol = 63,000 Kbps times forward error correction = 41.9 Mbps

21500-2/3 8PSK Turbo can reach 54Mbps
http://www.sciatl.com/products/customers/white-papers/BCA-2002%20Ken%20Hanna.pdf

 

[alk753]

Thank you JimK2. That was a very interesting read.

 

[Pepper]

Interesting, I didn't notice one was QPSK and the other 8PSK.

 

[digiblur]

Interesting, I didn't notice one was QPSK and the other 8PSK.

It's actually considered Turbo QPSK. You'll notice a standard QPSK tuner on a FTA receiver can't "see" the signal.

 

[digiblur]

Other interesting pieces of "hmmmm..." information:

How many QPSK TP's does Dish run at 7/8 FEC? 1 119W-TP11

How many circular DBS band QPSK TP's does Dish run at 1/2 FEC? 1 - 110W TP 25 Spotbeam 08. Why? Good question....users on the fringe area?

How many QPSK TP's does BellExpressVU run at 7/8 FEC? All of them.

How many 8PSK TP's does BellExpressVU run? Zero.

 

[Smith P.]

To cold up there to keep high density modulation .

 

[alk753]

How many QPSK TP's does BellExpressVU run at 7/8 FEC? All of them.

BEV's Nimiq1 runs about half at 7/8 and half at 5/6

Nimiq2 runs all at 5/6

 

[digiblur]

BEV's Nimiq1 runs about half at 7/8 and half at 5/6

Nimiq2 runs all at 5/6

Better tell their engineers to get their DVB tables fixed then. As of 5/20, they have all of the TP's listed at 7/8.