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[TowerTalk] MFJ 249/259 Calibration Procedure

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Subject: [TowerTalk] MFJ 249/259 Calibration Procedure
From: "" (Edward W. Sleight)
Date: Mon, 28 Jul 1997 21:18:43 -0700
Rick's comment is surprising, since MFJ sent me the complete calibration
procedure a few months ago, but FWIW, here is the SWR and Impedence

1. Set the unit to the 1.8-4 Mhz band.

2. Make a 100 ohm dummy load (100 or 2 50 ohm in series or whatever
installed in a PL-259 with leads as short as possible. 

3. Looking at the circuit board with the tune capacitor at BOTTOM RIGHT,
IC1 is about 20% down from the top on the right side of the board.
The pot to the left of IC1 is R-17, the SWR adjustment. The pot in the
middle of the 3 below IC1 is the resistance pot. 

OK, here we go...

4. Turn the unit on 

5. Use the 100 ohm dummy load and adjust R17 until a 2:1 SWR is

6. Replace the 100 ohm dummy load with a 50 ohm dummy load.

7. Adjust R31 until 50 ohms resistance is read.

8. Repeat as necessary until SWR reads 1:1 and impedence meter reads
50. ( never could get mine exactly on 50, but close enough )

And that's it. Don't mess with R-32 ( left hand pot ) or R-18 ( right 
hand pot ( AGC ).

BTW, just in case anyone is interested, the pin numbers for IC1 are:
Pin 1. Bottom right. Pin 7 Bottom left. Pin 8 Top left. Pin 14, Top

Hope this helps.



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