Solved: Lost all my HD channels, but not a signal problem

[iankb]

For the last week, all of my HD channels from the UK Freeview Hannington transmitter were intermittingly missing or corrupted. The odd thing was that no transmitter problems had been reported, the signal strength in Media Center displayed the normal 60%, and my TV had no problems.

The obvious thing was that the HD channels use MPEG4, whereas the SD channels use MPEG2. Therefore, I wondered whether my codecs had been corrupted or their priority altered.

In fact, I resolved the problem by simply installing the Matroska splitter from http://haali.su/mkv with its default settings.

This also allowed me to view all of my mkv files with other applications (including Media Center), which previously could only be viewed with VLC.

It's possible that an upgrade to Quicktime, or some other piece of software, may have caused the problem, and I have no idea why installing the Haali Splitter resolved it, but this information may help if unexpected 'signal' problems occur for anybody else with the HD channels.

By the way, the reason why I installed the Haali Splitter was because it was recommended as a prerequisite for the excellent AirServer application that allows my to mirror my iPad using AirPlay, without having to buy an AppleTV.

[morph]

I have been experiencing the same thing, but unfortunately for me installing the Matroska splitter has not solved the problem. After installing the splitter the HD channels were picked up briefly during a scan but were not accessible. Unfortunately at this point i thought the matter had been resolved and restarted the PC and scanned again - this time they were not detected at all.

I can see the channels using a TV with in-built Freeview HD so it is definitely not a signal problem.

Does anybody have any other ideas? I would be very grateful for any help.

[iankb]

Unfortunately, my problems came back after a couple of days. Coincidentally, the original problem started around the middle of December when they added extra HD channels to the Hannington transmitter. I think they may have made other changes to signal strength, and created more problems with crosstalk.

However, when I checked the signal for that multiplex on my LG TV, it displayed an (amplified) strength of 99%, and a signal quality of 100%, with no picture problems. Windows Media Center displayed the signal strength as the usual 60%, but with a frequent break-up or loss of picture.

I believe that I may have solved the problem for the moment, having taken the following actions ...

• I swapped over the aerial leads from my splitter/amplifier to my Blackgold quad tuner and my TBS dual tuner. I thought that maybe my 4-way splitter wasn't outputting the same strength on each output.
• More importantly, I checked the correct frequencies were ticked for each HD channel. I have up to 6 frequencies listed for each tuner, because there is a weaker relay from Crystal Palace in the direction of the Hannington transmitter. There was a rather odd situation where Media Center had decided to add the weak frequencies to BBC 1 HD as a priority, although not to other HD channels where the problem was most obvious. I wondered whether the tuners were selecting the frequencies from the first channel in the multiplex, and not as selected for each channel.
• I checked that I had the latest Blackgold and TBS drivers, that I had the latest graphics drivers, and that I had the latest full Shark007 codec package, which includes the Matroska splitter. Previously, I had uninstalled the separate Haali splitter.

I hope that this has resolved the problem. However, when I see the low power that some of these new HD multiplexes are being added with, and the issues with 4G masts that are being added, I don't trust that HD will always be a long-term option. Given that HD broadcast quality has been reduced significantly over the years, and the loss of my once-perfect 20-20 vision, I am resigned to having to use SD if that is the only reliable solution.