Overall view of the S-Band steerable antenna. This antenna was used to
communicate with Earth over the Manned Space Flight Network (MSFN).
As described by the Lunar
Module News Reference,
The S-band steerable antenna is a 26-inch-diameter parabolic reflector with a
point source feed that consists of a pair of cross-sleeved dipoles over a
ground plane. The prime purpose of this antenna is to provide deep-space voice
and telemetry communications and deep-space tracking and ranging. This antenna
provides 174° azimuth coverage and 330° elevation coverage.
The antenna can be operated manually or automatically. The manual mode is used
for initial positioning of the antenna to orient it within
&plusmin;12.5° (capture angle) of the line-of-sight signal received
from the MSFN station. Once the antenna is positioned within the capture
angle, it can operate in the automatic mode.
Picture 1 of 2.
Barely visible as a smudge on this web-resolution image, the horizontal portion
of the antenna leading to the steering mechanism on the LM mount bears the odd
warning "HANDS OFF".