Quote:
Originally Posted by terry j  I think we are (again???!!) mixing terms? I mean by rotating 180 the wells go 1234567 to 7654321, rather than 'turn it over' or upside down. |
Ah, there lies the confusion.
Because the panels are basically symetrical, your "flipped" panel would give the same diffusion pattern - no use as the alternate panel in a Barker sequence.
I think the more general usage of the term "flipped" is as I referred to above.
Whatever term is used to describe using the back of the panel, it's worth presenting the following drawing. It shows why the panel needs to be the full design depth to be used in this fashion. "Design depth" is the full half-wavelength of the design frequency. It's the depth of a standard inverse panel.
The first row shows that the back of a normal panel will have fins that are too short to allow it's use as an inverse.
In reality, the well bottoms have thickness that would require the panel to be deeper than the design depth by this amount.