Brand-new Rafale F4 undergoing trials at the DGA...
The transmitters are mounted on a wall, but there is cladding on all sides (and removable cladding can be placed on the floor).
The Rafale can be tilted by 15° in all axes, and different wavelengths are tested, from 140 MHz to 40 GHz, by rotating the aircraft through 360° (the suspension cables are made of fabric, not metal).
This is obviously used to qualify the RCS of the aircraft itself (in unarmed and armed configurations), but it also allows real-world measurements to be correlated with computer simulations, in order to validate the accuracy of the latter.
For this campaign, there was one measurement in armed configuration (I do not have the details of the configuration), and one in unarmed configuration.
To test all the other reinforced configurations, we use extrapolation: we measure the SER of the reinforcements and pylons in a smaller test rig, and then numerically combine all this data to determine the SER from all angles, in every possible and imaginable configuration.
Some say that we are also testing the effectiveness of SPECTRA
We can see a Rafale suspended in an anechoic chamber, likely for highly detailed electromagnetic measurements: radar signature, effects of the pylons, weapon load configurations, validation of numerical models, and also the qualification of certain SPECTRA behaviours.
The key point is that this type of test debunks the simplistic notion that the Rafale is merely a ‘non-stealth’ aircraft to which a good jammer has been added. The reality is much more subtle: Dassault and the DGA are measuring the aircraft’s actual signature under controlled conditions, across a very broad spectrum, and then correlating these measurements with numerical models. This then makes it possible to predict the SER according to angles, frequencies, external loads, pylons, fuel tanks, missiles and operational configurations.
Testing from 140 MHz to 40 GHz is particularly interesting. This covers everything from low-frequency detection bands to the higher bands used for fire control or radar imaging. In other words, the focus is not merely on the “marketing” RCS in the X-band at the front, but on how the aircraft behaves electromagnetically across the entire real-world radar environment.
And if SPECTRA is being tested in this context, it would make sense. A chamber of this type allows us to measure not only the passive echo, but also how an on-board system might respond to controlled emissions: reception, characterisation, transmission of countermeasures, jamming, active cancellation or related techniques. Obviously, the details remain classified, but the test bench is perfectly suited to this type of validation.
When a Rafale takes off with its payload, its SER depends on the configuration: missiles, fuel tanks, pylons, air-to-ground weapons, and any asymmetric charges. But as soon as a payload is fired or dropped, the electromagnetic geometry changes. A missile launched, a fuel tank dropped, a bomb fired, an empty pylon – all of these alter the radar echo and the radiation patterns.
If SPECTRA knows the initial configuration and receives information from the weapons system — shot fired, station cleared, missile launched, munition dropped — it can logically adapt its parameters: signature libraries, jamming tactics, transmission modes, threat management, vulnerability assessment based on angle and frequency. This transforms electronic warfare into a living system, linked to the aircraft’s actual status.
And this underscores the value of tests in an anechoic chamber. We are not simply measuring the “bare Rafale”. We are building a database of electromagnetic behaviour: the unarmed aircraft, the armed aircraft, pylons, weaponry, configurations, and intermediate states. The system can then utilise this data during operations.
SPECTRA does not protect an abstract Rafale; it protects the Rafale as it is at that moment, with its actual configuration and its firing history.
