Reduce Aircraft Transponder RF Leakage and Interference Using the ATC Transponder Faraday Shield Part # MDFF-ATC-SHIELD

The PROBLEM with only using an aircraft antenna coupler to reduce RF transmissions:

Today, there is an inherent issue with ground testing of an aircraft fitted with an ADS-B transponder. Since an ADS-B transponder automatically reports its position, this presents a problem for TCAS or ADS-B In equipped aircraft when testing above field elevation, especially around congested airspace. As a result, the FAA issued SAFO 17002 in 2017 to follow proper procedures and use antenna shielding to prevent test signals propagation.

Although antenna couplers are used to reduce the strength of aircraft transmissions, their attenuation capabilities are limited and may not be adequate to prevent your test event from being picked up by ATC and rebroadcast. Antenna couplers typically only provide around 25dB+ signal attenuation, which was once adequate to eliminate interference with TCAS equipped aircraft, but now ADS-B ground stations are positioned all over the globe and have a much greater level of sensitivity (around -84dBm)—which can pick up RF leakage from your test event if not properly shielded and rebroadcast your test aircrafts position causing interference with TCAS and ADS-B In equipped aircraft.

Test image and corresponding details can be found in the Reducing RF Leakage Using VIAVI Solutions Antenna Couplers report link below.

The figure demonstrates the problem with inadvertent RF transmissions. The potential of creating a False Intruder is based on the antenna coupler RF Leakage, isolation from the hangar, and the relative distance of the Ground Station to the Testing Location. In order to minimize the chance of creating a False Intruder, a Transponder Cover should be used to increase RF shielding effectiveness in test environments. This greatly reduces the likelihood of getting reprimanded by FAA for inadvertent transmissions.

The SOLUTION to increase aircraft transponder shielding effectiveness:

The Mission Darkness™ ATC Transponder Faraday Shield is the best solution for maximizing the attenuation level in order to prevent unwanted aircraft transponder transmissions/interference. The shielding effectiveness (attenuation level) drastically increases when the ATC Transponder Faraday Shield is placed over the antenna coupler affixed to the aircraft fuselage. It is sized specifically to cover antenna couplers, and has a 4-inch border of TitanRF™ Faraday Tape on all sides, so it can be adhered directly to the aircraft simply and effectively. Using the ATC Transponder Faraday Shield, alongside the coupler, eliminates RF interference that may otherwise get picked up by nearby aircraft, or ADS-B ground station and rebroadcast as a false intruder.

The cover is built with three layers of high-shielding TitanRF™ Faraday Fabric, which uses a copper and nickel composition to block radio signals from low MHz to 40GHz. The material has been tested and certified by Keystone Compliance Laboratory to military standards MIL STD 188-125, as well as IEEE 299-2006. The lab certifications provides concrete proof to the shielding ability and effectiveness of the product.

The ATC Transponder Faraday Shield has been tested by VIAVI and numerous airlines. It is the recommended product to use alongside antenna couplers, like the VIAVI UC-584s, for blocking signal transmissions, thus preventing the propagation of test signals.

The ATC Transponder Faraday Shield gets affixed directly to the aircraft fuselage, over the antenna coupler. It can be easily removed without damaging the aircraft surface.