[SOLVED] TBS DVB-T2 signal issues

[loddonlily]

I've been using a TBS 6280 dual DVB-T2 card more or less successfully for some time. Recently I decided to rearrange my kit and wanted to move the backend to a different machine - both the old and new machines were Ubuntu 20.04 with Myth 0.31, current TBS open source drivers. I can't say it was painless but I got it mostly working in the end!

But I am now having huge problems with signal loss (blocky, pixellating) which I wasn't having before. A picture (UK Freeview HD) will be fine for a little while but then start losing it either in little glitches or bigtime. TVs using the same aerial feeds are fine (I have a large loft aerial and distribution amplifier),

In an attempt to give myself a baseline when playing with aerials and amplifiers I've been experimenting with "femon -H" which supposedly is telling me something about signal quality - but unfortunately I never ran it "before" so I'm not altogether sure what normal looks like. What I've read online indicates that the numbers shown are not comparable across drivers, so I'm really looking for some other TBS users to give me some references.

Here is some typical output (one line per second or so):

Code: Select all

status SCVYL | signal  82% | snr  46% | ber 453434 | unc 0 | FE_HAS_LOCK
status SCVYL | signal  82% | snr  47% | ber 454980 | unc 0 | FE_HAS_LOCK

Then it might switch to this:

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status SCVY  | signal  83% | snr  11% | ber 532480 | unc 0 | 
status       | signal   0% | snr   0% | ber 0 | unc 0 | 
status SCVY  | signal  83% | snr   8% | ber 532480 | unc 0 | 
status       | signal   0% | snr   0% | ber 0 | unc 0 | 

... while it's doing this the picture seems to be ok, but it never lasts long.

Can any TBS users give me a reference point? Are there better tools I could be using?

I've already taken a flyer on my problem being the amplifier and got myself a new one - no change. I've also tried using different aerial outlets, hopefully eliminating a cable issue. I COULD get a new tuner but they're not cheap and I'd really like to do some sensible troubleshooting...

[loddonlily]

Continuing to play with this: I moved the TBS card back to the previous server in case there were something subtly different about the driver, say, but got similar results. For a while it looked like one tuner was working and the other wasn't ... so I disabled the "faulty" one by removing its adapter from the Backend and ran without glitches for several minutes ... and then it started cracking up again. So I'm still looking for help with TBS diagnostics...

[kmdewaal]

My first guess would be a cable/connector issue. Try to put the cable/connector that you put in the TBS card in a real TV and check if it that is OK.

[loddonlily]

My first guess would be a cable/connector issue. Try to put the cable/connector that you put in the TBS card in a real TV and check if it that is OK.

Fair guess, but no. I've tried the server in two different locations, each of which has a separate feed from the amplifier, and in each case I've also tested the cable with a real TV. I've also replaced the amplifier.

I'm facing up to the possibility that the tuner card may be at fault, I'd just like to know from another TBS user what their numbers look like...

[loddonlily]

I'll mark this as "solved" not because I have exactly but more because I'm giving up! As always, there seem to have been several things going on at once. My aerial was not ideally pointed - I've tweaked that for a small improvement. I think my TBS tuner is partly broken - I've bought a Hauppauge WinTV Dual USB and it is working, although it seems not to be as sensitive as the TBS was. Oh, and just for good measure, there is some transmitter maintenance going on today! The end result is that I can receive the HD channels reliably, which is all I really care about - the SD ones for some reason are not so good but that might be connected to maintenance - I'll find out over the next few days.

One good thing about using "femon" ... I was able to use it (in my loft, on a laptop, TeamViewing back to my server) to monitor output while tweaking the aerial (though this only seemed to work if the adapter was actually in use at the time).