Azbox on 7/8 FEC transponders

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B.J.

B.J.

SatelliteGuys Pro
Original poster
Oct 15, 2008
2,029
1
Western Maine
If anyone runs across any transponders with 7/8 FEC, I'd be interested in whether your Azbox will lock the transponder with multiple FEC and modes.

I ran into a DVB-S QPSK feed this morning with 7/8 FEC, and it did VERY strange things with my Azbox. I found the signal via a spectrum scan, and determined it's SR via SW method, then went to the Azbox, and tried to lock it. It turns out that the Azbox will lock it in ANY FEC value in DVB-S mode, and it will lock it in AUTO, 1/2 and 4/5 when set to either DVB-S2 QPSK or DVB-S2 8PSK mode. Not only that, it will scan in the channel in either QPSK or 8PSK, DVB-S or DVB-S2.

I find this very odd, and I'm guessing that it has something to do with the fact that the Azbox DVB-S2 tuning includes the 7/8 FEC value, which is an illegal value for DVB-S2, and that when it sees a real 7/8 FEC value, that it gets all confused.

Anyway, the signal I found was only a temporary feed, and it has since gone off line, so I'm now trying to find another signal with 7/8 FEC to try, but I'm not sure where one is. So if anyone knows of a 7/8 FEC transponder, it might be interesting.
 
OK, I just found another.
G-17 3840 H / 29270 7/8 FEC

On this transponder, with DVB-S2 QPSK I can lock in AUTO mode. In DVB-S2 8PSK, I can lock in AUTO, 1/2 and 4/5 FEC. In DVB-S QPSK, it locks in ANY FEC value.

I'm curious whether other people observe the same thing.


EDIT: I scanned in the FTA channel on this mux while in 4/5 FEC DVB-S2 8PSK mode, and it scanned in and plays fine. I used MAZ-3.0 to download channel data, and verified that it is indeed in 8PSK mode, and yet this is a DVB-S QPSK transponder.
Wierd.
 
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The Patient Channel Transponder on 87.0°W AMC 3 Ku has a 7/8 FEC (11716 H 4856)
The Teleuisa Tijuana Transponder on 116.8°W SatMex 5 Ku (Receivable in Southern US and Mexico) also has a 7/8 FEC (11977 H 1562)

On the Ku band the other 7/8 FEC transponders are data transponders.
 
Thanks QWERT. My Azbox is only on C-band right now, but after my first post I found a bunch of other C-band examples. I forgot I had a searchable list.

In my 2nd post, I tried one on G17 that I just happened to be on, and it did almost the same thing. I'll try some other ones later.
 
nycrich said:
Most important..what rev are you running? I'm using 9.4890 and not having those issues either in blind scan or manual
Click to expand...

Thanks.
I'm using an Azbox Elite with 0.9.4585 firmware. Behavior with another unknown firmware version was confirmed by a poster over on the Rick's forum. Some people on Satforums have stated that this is a known bug, and happens with other transponders, not just those with 7/8 FEC. I have not noticed this before with other transponders, but I may just not have noticed the behavior.
I often find transponders using a spectrum scan that only tells me the freq, then I find the SR using the SW method, so at that point, I need to determine the modulation type and FEC, so I go into the Azbox, and create a new transponder, save it, then go back into it and step through all the FEC options for DVB-S, DVB-S2 QPSK, and DVB-S2 8PSK until I obtain a lock, and normally I will only get a lock with one FEC/modulation value, so I can be confident of the parameters.
There was one other senario before this, where the Azbox would lock on more than one parameter set, and that was in cases where the transponder was DVB-S2 QPSK. In that case, I think I could get the Azbox to lock as DVB-S2 8PSK with a FEC of 7/8 (I think this was the behavior), and later found out that the 7/8 FEC was an illegal value for DVB-S2.
Locking with the wrong FEC value is something I've also observed with my TT-3200 receiver. It will generally lock no matter what FEC value you use, and I have gotten used to that, and that is why I need to use the Azbox to determine transponder parameters, since I can't do that with the 3200. However the 3200 will at least determine whether the transponder is DVB-S or DVB-S2. With the behavior I'm seeing, I could get the receiver to lock in any of the 3 modulation modes. However I guess that from what I've seen, if it will lock in DVB-S mode, then I think it has always been QPSK, as I don't think I've seen any examples of an S2 transponder locking in DVB-S mode yet, but since the posters on Satforums say this behavior is common, perhaps I need to study more transponders, as I may have just not noticed that this was happening before.

Anyway, thanks. I guess it's good news that this apparently doesn't happen with the PLUS version (I think that's what you're using), as it would be a real negative if a blind scan came up with the wrong parameters.
 
Transponder 4008H 2480SR from G17 C-Band wouldn't lock on the AZBox Elite with FEC of 7/8. I cycled through all FEC with no luck. :(
 
Babadem said:
Transponder 4008H 2480SR from G17 C-Band wouldn't lock on the AZBox Elite with FEC of 7/8. I cycled through all FEC with no luck. :(
Click to expand...

Same result here, if I set the freq on 4007, however if I changed it to 4008, then it locked fine S/Q=99/92 . They make it so hard to change a freq by one unit though, that it's hard to experiment like that. You have to delete first then re-do the whole thing.

Anyway, it worked for me at 4008.
 
B.J. said:
Same result here, if I set the freq on 4007, however if I changed it to 4008, then it locked fine S/Q=99/92 . They make it so hard to change a freq by one unit though, that it's hard to experiment like that. You have to delete first then re-do the whole thing.

Anyway, it worked for me at 4008.
Click to expand...
I deleted and re added the transponder, but no luck. I doubt those S/Q=99/92 are from a MiniBud. :eek: Are you using a Minibud to lock this?
 
Babadem said:
I deleted and re added the transponder, but no luck. I doubt those S/Q=99/92 are from a MiniBud. :eek: Are you using a Minibud to lock this?
Click to expand...

No, it's on a 10' dish, but it's so warped and dented that it isn't much better than a mini-bud. That S/Q is about as high as I've ever gotten. Most of my channels are in the 50-80 range. I think it's generally easier to get high S/Q readings on narrow transponders.
 
putney said:
It locks with my Az on any FEC, but it takes about two seconds. Lyngsat list it as fec 3/4. Scans in as 'service 2' (univision)

Latest FW
Click to expand...
I'm also using the latest FW, but for some reason my AzBox Elite is not locking it. Azbox Elite shows zero quality, while Coolsat & DVB 2104D register a solid 66% and a fluctuating 50% respectively. What version of AZBox do you have?
 
putney said:
It locks with my Az on any FEC, but it takes about two seconds. Lyngsat list it as fec 3/4. Scans in as 'service 2' (univision)

Latest FW
Click to expand...

I forgot to mention this, despite the original topic of this thread. Yeah, the 4008 transponder locks with ANY FEC on my Azbox too, just like all the other 7/8 FEC transponders I've tried. The Azbox really seems to have issues with 7/8 FEC, and I suspect it has something to do with the fact that they seem to mix that with the DVB-S2 modes, where 7/8 FEC isn't defined. Issues with the 7/8 FEC are even weirder on the S2 transponders.
 

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