Frequency from    Horizontal waterfall
tuned RF          display moving left to right ----->

0Hz               ------- (Carrier)


312.6Hz   A            --
346.7Hz   B
384.6Hz   C
426.6Hz   D
473.2Hz   E
524.8Hz   F       --
582.1Hz   G            --
645.7Hz   H       --
716.1Hz   J
794.3Hz   K
881.0Hz   L
977.2Hz   M
1083.9Hz  P
1202.3Hz  Q
1333.5Hz  R
1479.1Hz  S

In this case the SELCAL code is AG-FH.