Comparison of ground wave ranges for various antennas using RATT in
the AN/GRC-142 (400 watts).
As a 15-foot whip approaches a quarter wave in length
(15 MHz) less power loss, longer range. As a 32-foot whip approaches
a full wave in length at 30 MHz, range decreases because radiation
pattern changes from low to straight up.
longest ground wave is 12-25 MHz for a 15-foot whip; 7-20 MHz for a