Different antenna. ADS-B is at 1090 MHz, and VHF air comms is more around 121-135 MHz. The same SDR radio can tune those two bands, but an antenna that works we

Different antenna. ADS-B is at 1090 MHz, and VHF air comms is more around 121-135 MHz. The same SDR radio can tune those two bands, but an antenna that works well for one would work poorly for the other.