MFJ MFJ-269C - Advanced 3 Modes: Z Characteristic & Coax Loss; Testing and Tuning Stubs and Transmission Lines; Testing Stubs

MFJ-269C Instruction Manual LF/HF/VHF/UHF SWR Analyzer
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7. To increase line length in degrees, press Gate. To decrease it, press Mode. When the desired length
appears, simultaneously press and hold Gate and Mode to lock it in. The display will now change to:
Line length
?
l = 78
o
Pressing Mode shifts the display to the Velocity Factor adjustment in step 2.
5.6 Advanced 3 (LF/HF/VHF only)
To access this mode, press and hold Mode and Gate until Advanced-3 appears on the display.
Advanced-3 is used for setting the SWR reference impedance to values other than 50 ohms, and to
measure line loss and SWR in systems other than 50 ohms.
Advanced 3
Note
: The analog SWR Meter does not change reference impedance in this mode. It continues to display
the 50-ohm normalized value. Only the display SWR changes.
5.6.1 Z Characteristic
After entering Advanced-3, the display changes to a default setting of Zo= 75. It also prompts the
operator to enter a different value (Z Characteristic?).
1. Zo may be re-set using Gate to increase or Mode to decrease the normalized impedance value.
2. After selecting a new Zo, press both Mode and Gate simultaneously to lock it in The display will
show (sample screen):
Z Characteristic?
Z = 35
0
3. The small flashing SWR symbol on the lower left means the on-screen reading is referenced to a new
Zo (see screen below). The meter, however, continues to indicate SWR normalized to 50-ohms.
4. Pressing Gate (by itself) changes the function back to the Zo setup mode. Pressing the Mode by itself
changes the measurement mode to Coax Loss (see 5.6.2 below):