This question is a little more than "how to directionally place twin antennas"

[Slo and High]

I have a question about twin antenna routing with a Tactic 625 receiver in a Radian 2 meter sailplane. I have studied dozens of suggestions but since this is a (foam) sailplane that could have a very high altitude in a good thermal, I am concerned about a vertical position of one of the 2 two antennas.

I believe I narrowed it down to 1 antenna running horizontally, and at least 3 inches away, the other antenna tip end mounted "vertically", pointing either up, or downward.
The best, and easiest routing is to the top of the fuselage in my case.

That leads me to this question: Assuming my Radian is VERY high, and the vertical tip is on the top center of the fuselage, pointing skyward, (and behind the cockpit), will that position be hard to pick up "that doughnut" of signal from the radio? Should I point the tip downward? (NOT easy to achieve in my setup).
Thanks in advance,
Slo and High (bob)

[fhhuber]

the shadowing issue won't be a factor with reasonable care about antenna orientation.

I would not point one straight up with just 2 antennae

Point them angled up maybe 30 to 45 degrees and away from each other such that the antennae are at 90 to 120 degrees to each other and separated a few inches.

Best reception is with the RX and TX antennae parallel to each other. Secondary is in parallel planes to each other. So if going high you do not want an antenna pointed straight up and down.

[doctormike]

Never thought of that... Thanks! Doc

[Slo and High]

Thanks fhhuber for that info. Glad I asked.
Slo and High bob