Confirmed on real hardware: setting POCSAG frequency to 155MHz makes
MMDVMHost exit immediately with "Received a NAK to the SET_FREQ
command from the modem" - the MMDVM_HS_Dual_Hat's ADF7021 chips are
tuned for UHF and can't physically retune to VHF 150-160. Since
MMDVMHost controls DMR/YSF/NXDN/P25/POCSAG through one process, this
takes the whole modem down, not just POCSAG - matches the "DMR turns
red after setting POCSAG" symptom reported.
The earlier commit (that added this range as green/valid) was wrong;
it gave false confidence for a frequency that hard-crashes the radio
service. Back to the original 144-148/220-225/420-450/842-950 ranges.
yuancheng
2c815cec02