(freq - Base) / Step

Base
851.00625

Step
000.00625

freq          dec    hex   note
============  =====  ====  ===========
851.16250     025    019   control
851.25000     039    0026  alternate
851.30000     047    002E  alternate
851.53750     085    0055
851.65000     103    0066
851.78750     125    007D
852.23750     197    00C4
852.53750     245    00F5
852.73750     277    0114
852.76250     281    0119
852.81250     289    0120
852.85000     295    0127
852.95000     311    0137
853.12500     339    0152
853.15000     343    0156
853.26250     361    0169
853.36250     377    0178
853.56250     409    0198
853.58750     413    019C  alternate
853.95000     471    01D7