SSR/IFF 1030 & 1090 (ADS-B), DME, GNSS L1 1575.42 / L2 1227.60, Iridium, Inmarsat, LTE 1700, amateur 1240–1300, ATC radar.
Established mechanism
Pulsed L-band radar can produce the microwave auditory effect (Frey) at high peak power. Average-power heating is the ICNIRP basis.
ICNIRP note
Public S ≈ 4.8–8.5 W/m². GNSS is extremely weak at the receiver. Mid-band public whole-body ≈ 6.65 W/m².
Specific human health risks
- Microwave hearing: pulsed RF perceived as clicks or buzz when peak power density is very high (historically radar techs).
- 1030/1090 MHz ADS-B/SSR are expected and pulsed — do not treat ordinary Mode S as a weapon.
- GNSS is ~−125 dBm; if you see a strong carrier on 1575.42 it is a jammer or spoof, not GPS itself.
At harmful levels
Documented at extreme occupational radar: microwave hearing, thermal cataracts (usually higher freq), burns. Consumer SDR saturates long before ICNIRP heating is reached.
Directed-energy relevance
L-band is inside historical high-power microwave and some directed-energy research. High-PRF, high-peak pulses that are NOT 1030/1090 deserve a directed-energy watch. Havana-syndrome hypotheses in the open literature often mention pulsed microwave in roughly 0.3–3 GHz — unproven.
Evidence: occupational