An F/A-18 is suspended in the Benefield
Anechoic Facility at Edwards AFB for the
purpose of testing antenna radiation patterns.
Photo: USAF / Sr. Airman Julius Delos
3/11/2009 - EDWARDS AIR FORCE BASE, Calif. -- The
772nd Test Squadron teamed up with Naval Air Weapons
Station China Lake in a joint effort to complete
antenna pattern testing on a Navy F/A-18C Hornet at
the Benefield Anechoic Facility at Edwards on Jan. 22.
The purpose of the antenna test is to evaluate how
the entire F/A-18C system affects the antenna's
pattern and what parts of the aircraft can
significantly change the pattern.
"We are trying to discover the areas at which the
radar is working properly," said 1st Lt. Christopher
Stilson, 772nd TS test engineer. "When building an
antenna, it is designed as a standalone system. Once
installed on an aircraft a lot of the structure of the
aircraft will affect how the antenna operates."
For this test, the team evaluated the installed
antenna pattern by having the F/A-18C Hornet in the
anechoic chamber and measuring the performance of the
radar while it was installed on the aircraft.
"This would be the most accurate that the testers
can get, more accurate than measuring the antenna
itself," said Lt. Col. Taylor Selden, 772nd TS
commander. "It represents what the pilot would really
encounter for performance when flying operationally."
To test this system, the test team disconnected the
aircraft radar from the power source, transmitted
energy in from an outside source and measured the
power received on the back end of the antenna.
"For that we needed a very quiet, isolated
environment, and that was what the chamber provided,"
Colonel Selden said. "It allowed us an opportunity to
get more accurate measurement."
The Benefield Anechoic Facility's size, the largest
in the Department of Defense, allowed the testers to
evaluate all the aircraft's radar at various distances
and angles. This enabled them to capture 384
individual test points.
"We were able to perform the full antenna pattern
test with greater distance between our transmit
antenna and the aircraft," Lieutenant Stilson said.
"The team also set up four different antenna
transmitters to give us different locations and angles
to the aircraft."
The antenna pattern measurement data will enable the
Navy to design a software model of the F/A-18C's
antenna pattern, Colonel Selden said. As a result of
this testing, the Navy will be able to simulate what
the F/A-18C's radar performance will be for a given
scenario prior to flight.
Colonel Selden said this is the first time the U.S.
Navy tested tested in the BAF. Hopefully, it will be
the first of many opportunities with other services
and really make this a "full Department of Defense
"The working environment is really great," the
colonel said. "It was a small cohesive team and they
were able to quickly go from start to finish for this
project. We have a really good outcome. We are happy
to help out the Navy to provide them the data they
needed so they can better understand what their
Source: USAF Press Release by Senior Airman
Julius Delos Reyes