The F-35A features two data link systems: Link-16 (omnidirectional) and MADL (Multifunction Advanced Data Link, directional). Link-16 transmits signals in all directions and generates an electronic signature that can be detected by adversary sensors. The use of Link-16 increases the likelihood that otherwise stealthy F-35s can be detected and tracked [9].
MADL, by contrast, uses phased-array antennas with tightly directed signals and offers Low Probability of Intercept/Low Probability of Detection (LPI/LPD) [10]. However, MADL only enables F-35-to-F-35 communication in stealth mode [11].
Integration into Switzerland's existing air defense system (FLORAKO) requires MADL ground stations. Available sources provide no evidence that Switzerland has ordered such ground stations [12]. Likewise, there is no evidence of a SATCOM order [12].
Without MADL ground infrastructure and SATCOM, the Swiss F-35 fleet is heavily reliant on Link-16 for communication with existing systems -- with the stealth compromises described above.
A tactical gateway solution envisions one F-35 deep in the operational area relaying data via MADL to a second F-35, which then communicates via Link-16 [13]. This solution requires at least two F-35s flying simultaneously. With a reduced fleet of 30 aircraft and a Mission Capable Rate of 51.5%, only 15 mission-ready aircraft are available on average [14] -- making the gateway solution resource-intensive.
What does all of this mean in plain language? Switzerland purchased a six-billion-franc aircraft whose primary selling point is invisibility. But this invisibility only works as long as the F-35 remains silent. The moment it needs to communicate with the ground control station -- and it must, in order to transmit a situational picture -- it broadcasts an omnidirectional signal at 200 watts of power in the L-Band (960-1215 MHz) via Link-16. That is like mounting a lighthouse on a submarine.
This is precisely where the problem lies: Russian and Chinese electronic intelligence (ELINT) systems are specialized in intercepting such signals. The Russian 1L267 Moskva-1 system detects Link-16 emissions at distances of up to 400 km with 360-degree coverage and forwards position data directly to S-400 air defense batteries [15]. The 1L222 Avtobaza-M system can track up to 150 emitters simultaneously and identifies individual aircraft by their electronic signature [16]. The AI-assisted brigade command system Bylina (RB-109A) coordinates electronic warfare across an 800 km front width in a fully automated manner [17].
On the Chinese side, the passive detection system DWL-002 achieves detection ranges of 400 to 600 km for combat aircraft and can locate Link-16 signals in three dimensions [18]. Chinese research institutes have also developed algorithms that use neural networks to identify Link-16 frequency-hopping patterns with a detection probability exceeding 80%, even with extremely weak signals [19].
The F-35 in stealth mode thus becomes a lighthouse for electronic intelligence: it is not the aircraft itself that gives away its position -- but its communication. And without that communication, the F-35 cannot transmit any situational picture to Swiss air defense. Switzerland faces a choice with no good option: stealth without communication or communication without stealth. In both cases, a fundamental part of what was presented as the primary argument for the purchase is missing.
[9] Schweizer Parlament. (2019, 27. August). Medienmitteilung FK-S
[10] Bundeskanzlei. (2020). Volksabstimmung vom 27.09.2020
[11] admin.ch. (2020). Federal Decree on the Procurement of New Fighter Aircraft
[12] armasuisse. Air2030 Hauptseite
[13] Schweizer Parlament. (2022, 9. September). GPK-N Bericht zum Typenentscheid (PDF)
[14] Air & Space Forces Magazine (2024). Air Force Mission Capable Rates Reach Lowest Levels in Years
[15] Jane's International Defence Review (2019). Russia's passive electronic surveillance capabilities
[16] Military Balance (IISS). Chapter 5: Russia and Eurasia -- Electronic Warfare Order of Battle
[17] Army Recognition (2024). Ukrainian Forces Destroy Rare Russian EW Vehicle RB-109A Bylina
[18] SIPRI Yearbook. China's Defense Electronics Industry
[19] IEEE Radar Conference Proceedings. CNN-based LPI Radar Signal Detection