There really isn't any -one- antenna that's always 'best' for DX. It always depends on propagation and the antenna's environment. A simple choice in polarization isn't always a deciding factor. If you've ever had both a horizontal antenna and a vertical antenna up at the same time and have been able to switch between them, you will have seen that at times either of the two may be the 'best' at specific instances. The signal coming up on one as it's fading out on the other is quite common. Simply a change in the propagation characteristics of the band of use at any particular time.
Fixating on one particular characteristic of an antenna isn't the best idea. The take-off angle is a good example of that. TOAs are variable, the lowest isn't always the 'best'. Signals can arrive at quite a few 'angles', not always the lowest. That's also a property of propagation, and limiting your self to only 'angle' means you can miss signals arriving at other angles (or they may be weaker).
If it's a matter of only being able to use one or the other, horizontal or vertically polarized, 'averaging' which of the two is most common for your particular situation is probably the thing to do, and using that type antenna. That requires some time to do that 'averaging' and having both type antennas to see which is most usable for you. I would also expect that 'best' polarized antenna to change over a longer period of time.
And then it comes down to which type would be most practical for you to put up. I think that is probably the deciding factor in a lot (most?) cases. I know that I've been in circumstances that either of those choices, horizontal or vertical, antennas has been impossible to have for some reason.
Oh well. You do what you can and don't worry about it... unless you just like to worry?
- 'Doc
