The RF Center Frequency for QAM Channel A. When QAM Transmission Mode is 'annexA-DVB' the range is 85,000,000 Hz to 999,000,000 Hz in 250,000 Hz steps. For 2x4/2x8 QAM Modules: When QAM Transmission Mode is 'annexB-ATSC-DCII' or 'annexC-Asia-Pacific' the range is 57,000,000 Hz to 999,000,000 Hz in 250,000 Hz steps. For 4x4 QAM Modules: When QAM Transmission Mode is 'annexB-ATSC-DCII' or 'annexC-Asia-Pacific' the range may be limited to 69,000,000 Hz to 999,000,000 Hz in 250,000 Hz steps. This limitation is dependent upon the HW version installed and number of channels enabled. The APEX will correct values not on a 250 kHz boundary so the user or management system does not need to enforce the step size. This parameter is configurable ONLY when Tuning Mode is 'frequency'. When Tuning Mode is 'channel', the value is set by the APEX using the selected Frequency Plan. @Range(step=250000)