Wireless Joint

OK, this may be a silly one, but I'm not understanding the answers I'm researching.

Recently purchased a chooching 21dBi gain parabolic grid antenna from netsolutions.shop (thewirelesshaven.com). There is a red arrow on the antenna stick portion (what mounts to the dish) indicating direction of polarity.

The question: Does this arrow point down (towards the Earth), point up (towards the sky), or at a 45 degree angle? While I am happy to experiment, there are several (4x) 10mm bolts to deal with which makes this a little painful.

I don't think it matters since the dish itself is round... I have mine at 45deg since my antenna is ovular.. This, at least in my head, balances the two polarities instead of one getting the full width of the dish and the other spilling over the top and bottom

Please understand the non-scientific nature of what I am about to say, as I have nothing but an hour's worth of experimentation to back it up:

• Arrow points down (towards Earth)

This appeared to give the most gain (primary and diversity antennas), as reported by the MOFI4500 (stock). Similar position and spot tests were performed with the arrow at the 45 degree (towards Earth), and the arrow at the horizontal (parallel to Earth).