Reg Edwards wrote:
In daylight, with vertical LF and MF antennas, all radiation at an
angle above 0 dgrees and that reflected from the ground, whuch is most
of it, is wasted and generally unwanted.

Only the groundwave is useful.

At night a virtue is sometimes made out of a vice.

While the above is generally true for broadcasting...

I, like hundreds of others, can work 1000 miles or more during mid-day
in winter on 160 meters. I, like many others, can work thousands of
miles in mid morning or late afternoon. It isn't unusual to hear and
work west coast stations that are 2000 miles away at 10 or 11 AM local
time, and that sure isn't zero degree takeoff stuff.

By the way the vast majority of AM BC stations use tower somewhere
around 1/4 wl tall. There is nothing to be gained by going taller
compared to the extra installation and upkeep expenses. AM BC stations
used to use 5/8th wave verticals in early years of broadcasting, but
they quickly learned that was actually a disadvantage because the earth
around the antenna wasn't good enough to allow the full gain. All the
extra height did was increase fading at modest distances.

73 Tom