Your total beam side tilt of 10 degrees is not fatal, but still less than
otimum. Several models average about 0.1-0.2 dB loss of gain and about 1
dB loss of F-B. Impedance change is not great. However, the pattern
begins to distort, even at 10 degrees, especially with respect to the
sides--which pinch in on the high side and flatten on the low--and a
slight misdirection of the main forward lobe.
All in all, I'd say that the biggest question may be mechanical: in the
slippage, has anything been started that is going the create a road to
something much worse? Moreover, when you have a reputation for being on
the level, a little tilt can ruin one's image.
Hope (most of) this is useful.
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