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Trimmer resistors in the MFJ-259B

Solution

 

I guess that the basic function for the MFJ259B, MFJ269 trimmers, could be extracted from the calibration procedures http://www.mfjenterprises.com/MFJ-259Bcalibration.php and http://www.mfjenterprises.com/man/pdf/MFJ-269_Calibration.pdf
 
Trimmer resistors for the MFJ259B:
 
-  Emitter follower amplifier bias resistor R84
 

- Vs (voltage drop in the resistor in series with the load):

            - Diode compensation circuit with R88

            - Amplifier with R73

 

- Vz ( voltage drop in the load):

            - Diode compensation circuit with R90

            - Amplifier with R72

 

- Vr ( reflected voltage):
         - Diode compensation circuit with R89
         -  Amplifier with  R53
 
- SWR needle meter adjustment R56
 
- Impedance needle meter adjustment R67
 
 
Trimmer resistors for the MFJ269:
 
-  Emitter follower amplifier bias resistor R84
 

- Vs (voltage drop in the resistor in series with the load):

            - Diode compensation circuit with R108

            - Amplifier with R73

 

- Vz ( voltage drop in the load):

            - Diode compensation circuit with R109

            - Amplifier with R72

 

- Vr ( reflected voltage):
         - Diode compensation circuit with R28
         -  Amplifier with  R53
 
- SWR needle meter adjustment R56
 
- Impedance needle meter adjustment R67
Article details
Article ID: 69
Company: MFJ
Date added: 2017-01-12 14:30:32
Views: 13

 
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