Pseudo-Franklins have been employed below 1400 kHz, however, to good effect, but no where near as good as a true Franklin; which has an efficiency of about 510 mV/m/kW at 1 km.
Pseudo-Franklins have been employed below 1400 kHz, however, to good effect, but no where near as good as a true Franklin. A true Franklin (180 over 180 degrees; 360 degrees, total) has an efficiency of about 510 mV/m/kW at 1 km. 
