Typical Input Resistance in Ohms Compared to Power Lost in dB
Versus Antenna Height.
by the U. S. Marine Corps and Collins Radio Co.
A full-scale antenna was erected and antenna
c u r r e n t distributions were measured at a num-
at the Panama Canal Zone in the jungle environ-
ber of frequencies. Radiation patterns and antenna
m e n t . Five test sites, varying from 10 to 300
gains are computed from these currents to pro-
m i l e s from the main transmitting site, were
v i d e full-scale performance data. Field patterns
selected. Jungle canopy varied from 50 to approxi-
are provided at a number of frequencies (figures
mately 200 feet. Comparisons were made, using
3-12 through 3-19) followed
by gain contours
the 637K Antenna and a 15-foot whip antenna.
t h e antenna plotted on a general propagation
All the tests confirmed the superior performance
of the 637K on short-range circuits.
p r o p a g a t i o n c h a r t , t h e antenna provides good
gain on short paths varying from 0 to about 300
The performance of the 637K antenna was veri-
f i e d in December 1967. Tests were conducted