If you are standing behind a normal dish with view to the satellite, the LNB has to be turned counter clock wise for all east positioned satellites. But in yor case you have an additional mirror and thus I believe your LNB has to be turned clockwise (seen from the same postion as described above).
1) Counter clock wise because it's east from my location, or clockwise with a negative angle, still meaning counter clockwise.
2) Then, inverted again: clock wise because of second mirror
3) And then again: counter clock wise because the LNB IS on the back of the dish
Conclusion: I have to turn it counter clock wise while standing behind my cassegrain dish, facing the satellite.
And indeed Remco, if you describe your position in relation to the dish when you're about to rotate the LNB, as "Facing the satellite", then it doesn't matter if you're dish has one or two mirrors.
My sanity check:
1) Two mirrors would cancel each other out, when it comes to any flipping effect no matter if it's up-side-down or left-to-right
2) So I can stand behind my dish, and just imagine how the polarisation from a satellite hanging over Africa (from the south-south-east in relation to my location) would look like:
[Blocked Image: https://pc7x.net/ccw.png]
Quote
In a linearly polarized system, a polarization misalignment of 45 degrees will degrade the signal up to 3 dB. Polarization misalignment near 90 degrees can result in signal degradation greater than 20 dB. Accurate measurements of signal strength at polarization near 0 degrees and from 80 degrees to 90 degrees require careful control of the positioner and signal strength meter.
So it should matter something like near 1dB I estimate, and something like double that, If I rotate in the wrong direction
Thanks everyone for the insight you provided.