Charleston, SC - The Naval Information Warfare Center (NIWC) Atlantic’s Radio Frequency Test Facility (RFTF) Poseidon Park, which tests antennas installed on military vehicles, is unique for several reasons, but most notably is that it is located outside and not inside an anechoic chamber – that is, a room that creates no echoes – like most radio testing facilities.
“Since it’s outside, we have more flexibility for testing antennas and transmitters installed on vehicles, small boats and airplanes that will be used by Sailors, Marines and pilots in the field,” said Daniel Smith, RFTF lead. “We have three turntables and a more than 30-foot-tall Gantry arm that can generate 2D and 3D patterns.”
Antenna pattern testing at the facility is conducted on either a 20-foot steel turntable capable of holding vehicles up to 55,000 pounds, composite 4-foot turntable for direction-finding and standalone antenna tests, or a 30-foot square, 18-inch-thick concrete pad to hold vehicles that weigh more than 55,000 pounds.
The Gantry arm provides a spherical representation of the antennas’ performance by taking both horizontal and vertical polarized measurements, at multiple azimuth and zenith angles, to produce a 3D representation of a particular antenna. Different probes are used for low frequency and high frequency tests. Pending weather, 3D testing runs can take up to 18 continuous hours to complete.
Radio frequencies are wireless electromagnetic signals used for telecommunications. The “frequency” refers to the rate of fluctuation of radio waves, which are a type of electromagnetic radiation. Radio waves broadcast television, internet, and cell phone signals.
Radio frequency testing is critical to the U.S. Navy and the Department of Defense (DOD) because it ensures that not only are the antennas and transmitters functioning properly in the field, but also confirms that there isn’t interference with other devices or systems. Testing at RFTF also determines safe standoff distances for ordnance, personnel and fuel.
“We start the process with voltage standing wave ratio (VSWR) testing, which is a simple test confirming everything is connected and working properly,” Smith said. “It also measures the efficiency of power transfer. A normal measurement is between 2 and 3, between 10 and 12 tells me that something isn’t working perfectly and anything higher tells me that there is a major defect.”
If the equipment passes, the test moves onto co-site and electromagnetic compatibility testing, which tests antennas and systems already installed on the same vehicle to ensure they don’t interfere with each other.
Another unique quality that the RFTF provides is the ability to write and develop custom software to complete testing on special projects.
“We strive to provide excellent customer service, so if someone has a specialized or unusual antenna, we can write software to test it,” Smith said. “We also work with the customer to find a solution if the system fails. It’s important to us that the equipment we provide to the warfighter won’t fail in the field.”
Author’s note: This is the second article in a three-part series. The first article about electromagnetic interference/electromagnetic capability can be found here:
https://dvidshub.net/r/mhxjtl. The third and final article is about Environmental Test and Evaluation Facility.
*While the Naval Information Warfare Center (NIWC) Atlantic is home to dozens of labs and testing sites, there are only two labs and one test site that ensure equipment and technology meet the necessary requirements to provide the warfighter with the safest and most advanced solutions to their challenges.