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Low Symbol Rates


Ratchet1966

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Hi, new member here who has recently purchased DVBViewer Pro. I am having trouble scanning transponders with very low symbol rates (i.e. under 2Msps). My device is a TBS Q-Box S2 CI and it can handle symbol rates of 1-45Msps in both DVB-S and DVB-S2 modes. If I use the manufacturer's own blind scan software it happily finds SRs as low as 1.3Msps but whenever I try to scan with DVBViewer or Transedit (both latest levels) I get nothing. I've tried a variety of TPs on both 11.0W and 12.5W that have sub 2Msps SRs and none of them can be locked despite being found by TBS blind scan. Anyone got any advice on how to resolve this, thanks.

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Does it take longer to lock on these transponders? If yes, increasing the PAT timeout in TransEdit (see Settings -> Scanner 2) could help.

 

Or try the TransEdit Analyzer. It waits forever, if necessary.

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..try the analyzer of transedit. You also could increase the PAT Timeout in transedit (-> settings -> Scanner 2). If your card works with altdvb you can check the lock time ;)

 

/edit

oops, @Griga was faster :)

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I had previously tried Analyze in Transedit without success. Following your advice I increased the PAT timeout by a factor of 10, again without success. I can confirm that the signal strength is fine as my Technomate STB connected to the same LNB has a solid lock on these TPs.

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With TBS Blind Scan I can detect the following low SR TPs.

 

11.0W

11507 H 1240 DVB-S2 8PSK 2/3

11521 H 1817 DVB-S QPSK 7/8

11548 H 1599 DVB-S QPSK 2/3

 

12.5W

12528 V 1299 DVB-S QPSK 3/4

12682 V 1707 DVB-S2 QPSK 3/5

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My device is a TBS Q-Box S2 CI and it can handle symbol rates of 1-45Msps in both DVB-S and DVB-S2 modes. If I use the manufacturer's own blind scan software it happily finds SRs as low as 1.3Msps but whenever I try to scan with DVBViewer or Transedit (both latest levels) I get nothing.

 

Finding and locking a carrier is one thing, getting useful data is another. IMHO TBS is not telling the truth. I've purchased a 8921 because they advertised with blind scan and low SR-capabilities. Here the result for 12.5W, 12528V. The analyzer shows a broken multiplex. Though the SI tables are found, the output contains crap. With the given modulation parameters: DVB-S, 1300, 3/4 the netto data rate should be 1.8 Mbit/s, but the analyzer reads 15,5 Mbit/s. I've asked question about this in the tbs forum but got no reply. I suspect that your card shows the same poor performance. Maybe it's just a crappy driver..

 

The same transponder with another TBS card. This time the 6925 which shows an excellent performance but at a much higher price :rolleyes:

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Thanks for the info Derrick, here's hoping it's not simply poor hardware and can be fixed with a driver update from TBS. I bought it for primarily for it's Common Interface and blind scan capability - low symbol rates weren't really a factor. Having said that I don't like not being able to access advertised features. I appreciate this is not a DVBViewer issue and thanks again for your replies.

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Well done to TBS, they supplied an updated driver within 48 hours of reporting the issue. I am now able to lock signals below the advertised range of the device. See attached screen cap for a signal lock on a symbol rate of 716 !!

post-114693-0-19752400-1314810176_thumb.jpg

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