CT Spectrum Management Association
Connecticut's Amateur Radio Operator's frequency coordination group
GE Mastr II Crystal Calculators

Select the Mastr II Combination number that matches your unit.  Type in the frequency you wish to use for transmit or receive in the appropriate field, then click outside the box.  The xtal frequency will appear!  If you have a xtal and want to see the frequency where it can be used, enter the xtal frequency in the appropriate field, then click outside the box.  Always double check the math before ordering crystals.  Get General Electric Mastr II Icom details at Hall Electronics.

General Electric Mastr II ICOM Oscillator Frequency Calculation
Transmitter
Model Combination No.
Freq Range Digits
Freq Band Formula Crystal Range (MHz)   Tx Freq Fo Xtal Freq Fx
12 25-30 Fo /3 8.33-10
13 29.7-36 Fo /3 9.9-12
23 36-42 Fo /3 12-14
33 42-50 Fo /3 14-16.67
33 Extended 50-54 Fo /3 16.66-18.00
44,45 66-88 Fo /6 11-14.67
56 138-155 Fo /12 11.5-12.92
66 Extended 144-148 Fo /12 12.00-12.33
66 150.8-174 Fo /12 12.56-14.5
56, 66 Modified 222-225 Fo /18 12.33-12.5
77 406-420 Fo /36 11.27-11.66
78 420-450 Fo /36 11.66-12.55
88 Extended 440-450 Fo /36 12.22-12.55
88 450-470 Fo /36 12.5-13.05
89 470-494 Fo /36 13.05-13.72
91 494-512 Fo /36 13.72-14.222
General Electric Mastr II ICOM Oscillator Frequency Calculation
Receiver
Model Combination No.
Freq Range Digits
Freq Band Formula Crystal Range (MHz)   Rx Freq Fo Xtal Freq Fx
12 25-30 (Fo+11.2) /3 12.06-13.73
13 29.7-36 (Fo+9.4) /3 13.03-15.13
23 36-42 (Fo+11.2) /3 15.73-17.73
33 42-50 (Fo+9.4) /3 17.13-19.8
33 Extended 50-54 (Fo+9.4) /3 19.8-21.13
44, 45 66-88 (Fo-11.2) /6 12.86-16.54
56 138-155 (Fo-11.2) /9 14.08-15.98
66 Extended Low Inj 144-148 (Fo-11.2) /9 14.75-15.2
66 Low Inj 150.8-174 (Fo-11.2) /9 15.51-18.08
66 High Inj 138-174 (Fo+11.2) /9 16.57-20.57
56, 66 Modified Low Inj 222-225 (Fo-11.2) /12 17.56-17.82
77 406-420 (Fo-11.2) /27 14.62-15.14
77 Extended 420-430 (Fo-11.2) /27 15.14-15.51
78 420-450 (Fo-11.2) /27 15.14-16.25
88 Extended 440-450 (Fo-11.2) /27 15.88-16.25
88 450-470 (Fo-11.2) /27 16.25-16.99
89 470-494 (Fo-11.2) /27 16.99-17.88
91 494-512 (Fo-11.2) /27 17.88-18.54
  450-512 (Fo+11.2) /27 17.08-19.38
92 806-820 (Fo-45) /48 15.85-16.25

W1AN Copyright 1992, 2023