This pissing contest is exactly why I stopped posting in this thread.
one person has turned his lack of knowledge into an attack on basic antenna 101 and anyone that believes it.
For the record, NVIS operations in Iraq were conducted in the 2 to 4 Mhz range at night and in the 4 to 8 Mhz range during the day.
Mobile operations used the standard (5 meter) vertical whip antenna, most fixed stations used the Shirley dipole array.
as with all NVIS propagation, the effective distance is a factor of the radiation angle,... which is a factor of the antenna height above ground.
Antennas at heights (above 1/10 to 1/4 wl) WILL direct the signal at too low an angle and it will not be reflected by the ionosphere. No NVIS propagation will be produced.
NVIS operation will fill the distance gap between GROUND WAVE propagation and F-2 propagation.
Attempting to use NVIS while within the Ground wave coverage distance WILL deteriorate the received signal due to multipath reception.
Bottom line: For NVIS operation, use a low mounted horizontal antenna, (with a reflector below it if possible), and use the correct frequency .
Compared to other lower bands, There is very little NVIS on 40 meters ( it is near the high end of the usable band) during the day, and none at night.
