Well, that spot is really small. Most people mentioning this problem are talking about losing the plane because the signal is too strong. Don’t know which problem Yates is having.
See this post: Diversity Reception - #7 by wiedehopf
Are you talking planes at >20000 ft or low flying planes?
Also see the link i posted above in regards to that blind spot.
Of course different antennas are different in regards to that spot.