Trucking a Giant Feed Horn
The L-band feed horn is one of the largest feed horns used on our radio telescopes. The size of a feed horn is related to the size of the wavelength that it funnels onto its receiver. L-band wavelengths are 20 centimeters long, so the narrow end of this horn is 20 cm wide where it turns the wavelength into a voltage. If the open end were less than 20 cm across, the waves would simply see it as a mirror, and bounce away. The wider the mouth of the horn is, the more waves can enter the receiver without being lost.
Credit: NRAO/AUI/NSF
