Mode S is 1030/1090 MHz, and L-band/S-band Primary Surveillance Radars ('real' radars) are still quite in use, especially in ground-based surveillance or Air Tr

Mode S is 1030/1090 MHz, and L-band/S-band Primary Surveillance Radars ('real' radars) are still quite in use, especially in ground-based surveillance or Air Traffic Management. In fact 4G and wimax were threatening civilian radar bands.