Eckard,
I see your point, but consider; The waves know nothing of the approaching medium so their speed in the background is relative c plus v in the medium frame.
Lambda then changes in the new medium (which may be a lens or any detector) inversely to frequency. (That is the part often ignored and which it seems Pentcho cannot see the consequences of).
Once the moving medium is traversed (at c in the medium frame) that moving medium ecomes an emitter. Still in that frame, the waves will then be emitted at, and travel at c (in the near field). The speed is then c not c+v, and the wavelength is thus altered.
The really cool bit about Peters model is that he finds (for the far field) how and why the waves then revert to what you propose (not shown in my fig), which is identical to the approaching waves, so relative c plus v again!
The magnetohydrodynamic coupling mechanism is shown in my next diagram (which Peter refers to as equivalent to a fluid dynamic torque converter (as an auto gearbox, but linear) i.e. the particles all emit at c locally, but are in different states of motion, so mechanistically evolving c to c'.
There is classical observed 'Relativity' direct from a quantum mechnism, which is what Einstein was searching for, and probably the biggest breakthrough in physics for over 100 years. It's sad and surprising that nobody seems to have yet noticed or understood. Perhaps it's that most minds only work mathematically not logically?
Rich
PS. No Judy is not related to me