Can you check Signal Quality (not just strength)?

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jaybeedee

64 posts

Master Geek
+1 received by user: 4

#119159 22-May-2013 18:38

We have a problem on TV3 and TV4 only. They occasionally suddenly break up and start pixellating badly.

It happens on both the 570 and 562MHz. Signal strength is 100% on one of them, 97+ on the other.

Is there anyway on Tivo to check signal quality?

It doesn't seem to be weather related or tied to any appliances being turned on or off.

I wondered about posting this in the freeview or Tivo forum. the problem was first noticed sometime after we reinstalled sky and moved the Tivo to the bedroom. so there has been a combination of changes in the cabling (including the sky techs combining our Aerial and Dish feeds then splitting them again at one of the outlets) and of course the cables I terminated could be dodgy but it seems to only be on TV3/TV4.

Spyware

3818 posts

Uber Geek
+1 received by user: 1366

Lifetime subscriber

#823711 22-May-2013 19:04

Describe the antenna setup, where they point, polarity etc.

Spark Max Fibre using Mikrotik CCR1009-8G-1S-1S+, CRS125-24G-1S, Unifi UAP, U6-Pro, UAP-AC-M-Pro, Apple TV 4K (2022), Apple TV 4K (2017), iPad Air 1st gen, iPad Air 4th gen, iPhone 13, SkyNZ3151 (the white box). If it doesn't move then it's data cabled.

Skolink

1081 posts

Uber Geek
+1 received by user: 32

#823851 22-May-2013 22:49

Yes. Messages & Settings>Account & System Information>Media Device Diagnostics.
MER should be 300+
Pre-Viterbi Errors: not sure, 8000 and counting on ours. Assume should ideally be 0
Post-Viterbi Errors: 0
Packet Errors: 0

jaybeedee

64 posts

Master Geek
+1 received by user: 4

#824406 23-May-2013 20:43

Thanks for that, So I went and looked up pre-viterbi and found this interesting article on

http://help.telecom.co.nz/app/answers/detail/a_id/5113/~/pixelated-or-scrambled-tivo-picture

To View the Media Device Diagnostics

Go to TiVo Central (select the TiVo button on your remote)
Select Messages & Settings
Select Account & System Information
Select Media Device Diagnostics

The Media Device Diagnostics will be displayed for one channel at a time. On the first screen that is displayed you will see what channel’s diagnostics you are viewing. To change the channel’s diagnostics you are viewing you have to return to Live TV, select the desired channel you want to know the diagnostics for then repeat Steps 1-5 listed above.
You can confirm again by the ‘Channel’ value to be sure what channel’s diagnostics you are viewing.

The fields we are interested in are MER, Pre-Viterbi errors and Post-Viterbi errors.

If the MER value is above 250 and that there are no Post-Viterbi errors this would indicate the picture issue is not being caused by the signal.
Generally speaking, an MER of 350 indicates fantastic signal, 300 is good signal, 250 is acceptable signal, and anything less than 250 is considered to be poor reception.
The presence of Post-Viterbi errors indicates that the number of signal errors was so great that the unit was not able to correct them all, and therefore there are errors left over after the Viterbi correction process.

If you do come across a customer with an MER value below 250 / showing Post-Viterbi errors, it would pay to check their coverage (http://www.mytivo.co.nz/whatistivo/tivoisfreeview/coveragechecker/) if not checked earlier. If their coverage is ok it is possible this could be due to an issue with the aerial.