@ -40,7 +40,7 @@ This software is licenced under the GPL v2 and is intended for amateur and educa
MMDVM_HS boards do not need deviation calibration like MMDVM boards, but could be necessary some frequency offset calibration (ADF7021 does not have AFC for 4FSK modes).
The following options in MMDVM.ini ([Modem] setion) have not any effect for MMDVM_HS boards:
The following options in MMDVM.ini ([Modem] section) have not any effect for MMDVM_HS boards:
TXInvert
RXInvert
@ -49,7 +49,7 @@ The following options in MMDVM.ini ([Modem] setion) have not any effect for MMDV
RXDCOffset
TXDCOffset
The following options in MMDVM.ini ([Modem] setion) are very important for MMDVM_HS boards:
The following options in MMDVM.ini ([Modem] section) are very important for MMDVM_HS boards:
RXOffset: RX frequency offset (HS RX BER improvement)
TXOffset: TX frequency offset (radio RX improvement)
@ -65,7 +65,7 @@ The following options in MMDVM.ini ([Modem] setion) are very important for MMDVM
# Important notes
The ADF7021 (or RF7021SE module) must operate with a 14.7456 MHz TCXO and with at least 2 ppm of frequency stability. For 800-900 MHz frequency band you will need even a better frequency stability TCXO. You could use also 12.2880 MHz TCXO. Any other TCXO frequency is not supported. Please note that a bad quality TXCO not only affects the frequency offset, also affects clock data rate, which is not possible to fix and will cause BER issues.
The ADF7021 (or RF7021SE module) must operate with a 14.7456 MHz TCXO and with at least 2.5 ppm of frequency stability. For 800-900 MHz frequency band you will need even a better frequency stability TCXO. You could use also 12.2880 MHz TCXO. Any other TCXO frequency is not supported. Please note that a bad quality TCXO not only affects the frequency offset, also affects clock data rate, which is not possible to fix and will cause BER issues.
Please set TXLevel=50 in MMDVM.ini to configure default deviation levels for all modes. You could modify this value and other TXLevel paramenters to change deviation levels. Use [MMDVMCal](https://github.com/g4klx/MMDVMCal) to check DMR deviation level and TX frequency offset with calibrated test equipment.