Ok... now I want to be sure I understand:
ADF_FREQUENCY, // |
ADF_500_HZ_TUNABLE, // | ADF frequency
ADF_EXTENDED_FREQUENCY, // |
As we know from the FAA and other resources, the ADF receiver can tune:
190.0 kHz - 1799.0 kHz
This allows pilots to tune:
NDBs: 190.0 kHz - 535.0 kHz (in CONUS)
AM: 535.0 kHz - 1799.0 kHz (Used by AM radio stations)
Finally, outside of CONUS some countries use 500 Hz increments (ie. 0.5 kHz steps).
So, I know that:
ADF_FREQUENCY
is returned as a BCD value in an UINT32 with that being in whole kHz (ie no 0.5 for outside CONUS).
Hence, at some point I'm guessing MS added:
ADF_500_HZ_TUNABLE
which is a boolean that when true means:
ADF_EXTENDED_FREQUENCY
is defined. This is also a BCD value but I am unsure of the coding, but suspect it encodes the 0.5 kHz digit.
Can someone clarify this one?
Patrick
ADF_FREQUENCY, // |
ADF_500_HZ_TUNABLE, // | ADF frequency
ADF_EXTENDED_FREQUENCY, // |
As we know from the FAA and other resources, the ADF receiver can tune:
190.0 kHz - 1799.0 kHz
This allows pilots to tune:
NDBs: 190.0 kHz - 535.0 kHz (in CONUS)
AM: 535.0 kHz - 1799.0 kHz (Used by AM radio stations)
Finally, outside of CONUS some countries use 500 Hz increments (ie. 0.5 kHz steps).
So, I know that:
ADF_FREQUENCY
is returned as a BCD value in an UINT32 with that being in whole kHz (ie no 0.5 for outside CONUS).
Code:
32 0
X X X X X X X X X X X X X X X X
1000s 100s 10s 1s
Hence, at some point I'm guessing MS added:
ADF_500_HZ_TUNABLE
which is a boolean that when true means:
ADF_EXTENDED_FREQUENCY
is defined. This is also a BCD value but I am unsure of the coding, but suspect it encodes the 0.5 kHz digit.
Can someone clarify this one?
Patrick
Last edited: