[TowerTalk] 20m stack switching question

[Bill Tippett]

10m is not 20m but I suspect the same effect applies:

"Using only the 45 degree azimuth, below is a plot of my takeoff angles for
all 3 antennas (   ), the bottom two (   ) and the bottom only (   ).  I
often find that all 3 are best for early openings (11-14 UTC), then the
bottom two take over and occasionally, very late in the day, the bottom
antenna alone is best.  Note that VOACAP propagation statistics (   )
indicate that 16 degrees is the maximum TOA to EU for my location."

http://users.vnet.net/btippett/terrain_&_toas.htm

Note that HFTA includes the VOACAP takeoff angle statistics mentioned
above.  A little modeling will answer your question far better than
anecdotes.  I discovered my statement above after many DX contests on 10m,
and HFTA confirms my experience.

73,  Bill  W4ZV