I'm having trouble to lock on tp 4020V/34286/DVB-S2/QPSK, using a 10' mesh dish.
It's just a blinking signal with no channels from scan.
Any suggestions ?
Since it only effects 4020V, it sounds like you're getting in-frequency interference from somewhere, like 5G, Microwave or perhaps a WiFi signal. This happens if you're near a 5G source, a neighbor's WiFi, or even your own, a military base or even an air port. If that's the case, you may have to relocate the dish using a building as a shield, if you figure out where it's coming from, or use what's called an "RF Fence."
Titanium Satellite makes an LNBF with WiFi & 5G filtering, but it will not filter out in-frequency interference. This kind of interference invades the incoming signal and happens between the 3.7-4.2Ghz frequencies and the only option would be blocking the source of the incoming interference. You can build an RF Fence that goes around the outer edge of your dish, but it's time consuming and a little weird looking.
It's kind of like building a fence around your yard. You might also check to see if the dish you're using is compatible with 2 degree spacing. If not, you could be experiencing side-lobe interference from an adjacent satellite with an active transponder on 4020V. If that's the case, everything has to be perfect with your dish, such as focal point, offset angle, making sure the feed is perfectly centered on the dish, F/D ratio and making sure the dish isn't warped slightly, and of course, properly aligned.
The most likely of these is side-lobe interference. You can follow this link to see how close the satellites are on either side of the satellite you're having trouble with.
https://www.tvrosat.com/cgi-bin/portal_charts.cgi
Hope this helps.