Calculation in Progress……..
The collinear dipole antenna consists of two or more 1/2 wavelength sections separated by a 1/4 wave phasing stub in the form of a coil. Unlike the coax collinear, the dipole version requires a ground-plane to operate.
Performs well and can be used for RX and TX purposes. It can be made from any
common copper household electrical wire. The thicker the wire, the wider the bandwidth of the antenna
from its center frequency.
Frequency calculations are based on radio waves traveling at the speed of light
299 792 458 meters per second.
Metric
A:
?
mm
B:
?
mm
C:
?
mm
Imperial
A:
?
"
B:
?
"
C:
?
"
Above images show a prototype collinear dipole built for 1090 MHz using this antenna calculator. Note a coax balan is recommended, this is needed to keep current from the antenna off the feed line and back to the TX unit. For receive only, no balan or current choke is needed.
This ground-plane collinear design is superior to the quarter-wave. Besides better reception (gain) it uses a bit more space than the 1/4 wave and is ideal for mast mounting.