Important Points for Diagnosis
Which DVBViewer-version do you use? Go to About/Info to find out. Is it the latest release? Have a look the the revision history.
What is the signal strength displayed in the status bar of the DVBViewer? Values below 40% may indicate a problem with the positioning of your dish or the LNB.
Do you use DiSEqC devices (e.g. a multiswitch) for receiving more than one satellite position (e.g. Astra/Eutelsat)? Are the DiSEqC settings in the channel list window adjusted correctly?
Are the distortions permanent or only temporary? They may be caused by strong rain or snow. A sleeping pigeon on the LNB? (this had been actually reported in the DVBViewer-forum)
Are all channels or only some of them affected by the problem? If it's the latter: Which channels are compromised? Do they have something in common (the same transponder for example)?
Do other TV-software work?
Tune a channel with the DVBViewer. Then start the TechniSat program Setup4PC. Click on the button status: What is displayed for the following values?
Signal quality in %: the more, the better
SNR (Signal to Noise Ratio, relation between signal and influences of noise) in db: the higher, the better (a good value is 12)
BER (bit error rate, only available with SkyStar2 revisions <2.6b): Should be 0. A small value (for instance E -6) should be OK, too. But it could indicate a bad signal quality (which is not the same as signal strength for digital reception)
ncorrect packets: Should be = 0. Otherwise, the reception is at least temporarily so bad that the automatic error correction (FEC) can't cope with it.
Check your wiring and connections. Coax-cables must not be bent or twisted. Check for a short-circuit or interruption in an antenna plug (a very frequent cause for problems)
Does another digital device connected to the same line also show problems?
Have or had you installed software for your DVB card other than that from TechniSat? There are known issues with EON. Did you buy a second hand card with unknown past?
Since when do the distortions occur? Have you installed new hard- or software? Did you make any changes to your system or the DVBViewer? Also have a look at the options described in chapter 7.