Re: TelliCast Missed Packets False Alarms


David J Taylor GM8ARV 🏴󠁧󠁢󠁳󠁣󠁴󠁿 🇪🇺
 

David

TBH I have no idea concerning EUMETCast USB devices. AFAIK the whole TS is sent to the PC over the USB cable.
Several users seem to have acceptable even good results with the TBS5925 (same ST chip stv0900 AAC as in SR1).
What I do know is PCIe cards with ECP3 bridges. I have fixed the OS ECP3 code for missed interrupts and added a
buffer size that can be selected for up to 8 transponders with CrazyCat. All modern PCIe cards use the ECP3 bridge.

EUMETSAT has added a minimum traffic to T2 to resolve the PCIe buffer delay problem from the dissemination side.
AFAIK there is no such thing on T1 for HVS-1. That means you still cannot receive HVS-1 alone using a MODCOD
filter. You always need BASIC to keep the PCIe buffers busy. So at least for PCIe cards "time to correct" is no issue.

Cheers,
Ernst
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Thanks for those details, Ernst.

USB is strange in that it's a polling system (1 kHz rate for USB 2, IIRC), but clearly good enough to keep "CD quality" audio running without breaks. With 55 Mbps TS rate - who knows!

I do receive HVS-1 alone on an Ayecka SR1 with MODCOD selection, but of course that's with a UDP link and network devices, not PCIe. On my PC Lund (TBS6903/BDADataEx) it does take HVS-1 only, using MODCOD "All", but no TelliCast running for the BAS PIDs. Works with zero packet loss when the signal level is sufficiently high and stable.

Cheers,
David
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