KØHA MFJ-1026 PAGE

Having three MFJ-1026 units I was curious to the action and range of its phase adjustment control on 160 meters. A Fluke 96B Scopemeter provided the readings and a Wavetek 3000 Service Monitor served as a signal generator for a RF signal on 1830 kHz. A 160 meter bandpass filter followed the Wavetek to better clean up its output at that frequency. Adjustment of the PHASE control had a negligible effect on the amplitude of the signal whose phase was being adjusted. I didn't write down numbers since the worse change was less 0.5 dB. The reason for the test was more to observe the effects of the phase control adjustment. I wanted to have a better understanding of how the lobe center and nulls were being effected on my phased Beverages by adjustment of the phase control. I "normalized" the effect of the readings so that 0: phase shift is shown with the PHASE control at "0" with the PHASE switch in the "NORMAL" position. My wiring used did not accurately reflect the phase relationship in this position. However, the amount of phase change per control movement is accurate as well as the effect of the invert switch. Those inversion shifts probably would have been even more in agreement if they weren't made after changing the switch and readjusting the control. The figures below show the amount of phase change due to the control adjustment and the effects of the PHASE switch:

     


         PHASE        PHASE        PHASE
        CONTROL      SWITCH:      SWITCH:
        SETTING      NORMAL       INVERT

           0            0:          184:
           1            2:          187: 
           2            7:          192:
           3           12:          198:
           4           16:          202:
           5           21:          204:
           6           28:          210:
           7           39:          221:
           8           61:          243:
           9          105:          293:
          10          162:          348:

I knew that there was a reason why I rarely have the PHASE control setting between 0 and 5...

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