DVB Scanning missing LCN

DeltaMikeCharlie

I have noticed that frequently, when TVH performs a DVB scan on a mux, it will not always detect LCNs even though on previous scans it may have. Also, other receivers in the house have detected the LCNs so they are known to be present.

Has anyone else noticed this too?

I have not looked into the code, but I suspect that because the DVB descriptor containing the LCN is separate to the PAT/PMT, perhaps TVH does not always wait for long enough to detect the LCN descriptor.

DaveH

Googling for the subject shows similar stories in the past using other recorder software. One possible hint is that it may be a poor signal. What antenna have you got and is there a strong signal?

DeltaMikeCharlie

DaveH What antenna have you got and is there a strong signal?

Thanks for your response, this is something that I have considered but I have other non-TVH devices on the same antenna feed and they all identify the LCN perfectly every time.

I have 5 OTA muxes in my area. Yesterday, 2 found LCNs immediately, 2 found LCNs on the second attempt and the remaining one took about a dozen tries. All 5 have EPG data and there are no breakups in the signal when viewing.

DaveH

With respect, the signal that other devices see isn't the same as your TVH, depending on how the signal is split and the cables and connectors used etc. Have you tried swapping things around? Have you measured the S/N ratio for the different muxes (TVH should show this)?

DeltaMikeCharlie

DaveH With respect, the signal that other devices see isn't the same as your TVH

My apologies, you are right, I was trapped inside my 'missing descriptor' hypothesis.

DaveH Have you measured the S/N ratio for the different muxes

S/N varies from 31.8 dB to 37 dB across my muxes.
Signal strength varies from -55 dBm to -45 dBm.

DeltaMikeCharlie

I did some more testing:

I noticed that after some time, the missing LCNs eventually turned up. I eventually realised that this occurred after the OTA EPG grabber had run.

I reset and rescanned my system and opened 2 windows, 1 watching the services and 1 watching the tuner status. As each mux was scanned for the OTA EPG, the missing LCNs appeared.

For a final test, I disabled the OTA EPG module and then reset/rescanned. The LCNs were still missing as expected and did not eventually populate. Next, I streamed 1 channel from a mux with missing LCNs and all of the LCNs for that mux suddenly appeared. This repeated as I streamed other channels from other muxes.