You can change the centre frequency by right-clicking on the large round arrows in the frequency bar.
If you change band or centre frequency it affects all users on that device.
SDR Device 1: RTL-SDR Blog V3. Antenna: UHF 5 ele yagi, vertically polorised, pointing West.
SDR Device 2: Airspy Mini. Antenna: UHF 5 ele yagi, vertically polorised, pointing West.
SDR Device 3: SDR Play RSP1A. Antenna: 30m (10Mhz) Inverted V dipole.
SDR Device 4: SDR Play RSP1A. Antenna: 4m (70Mhz) V Ladder line Slim Jim.