MFJ-269 Instruction Manual HF/VHF/UHF SWR Analyzer
30
Lin e le n g th ?
l = 1 0 0 .0 ft
o
6.) To increase line length, press the
GATE
button. To decrease line length, press the
MODE
button. When the
desired length appears, simultaneously press and hold
GATE
and
MODE
buttons. The display will now change
to:
Lin e le n g th ?
l = 6 7 .2 . ft
o
7.) Pressing
MODE
takes the display to length in feet for the degrees programmed at Vf selected.
5.5.3.2 Line Length in Feet
This mode displays the length in feet required to obtain a certain number of electrical degrees for the velocity
factor (VF) and frequency selected. It is useful for determining the physical length required for matching
sections, phasing lines, or antennas if the velocity of propagation, electrical length required, and frequency are
known.
This mode is useful for calculating the required length in feet of matching sections and phasing lines if you know
the required variables, velocity factor and electrical degrees. The analyzer can also directly measure and display
length using the distance to fault mode (sec 5.5.1 for HF/VHF).
If this mode is entered after using distance to fault (sec 5.5.1), VF and length will be programmed automatically
using distance to fault data. The physical or electrical length of the line can also be programmed manually. If a
length is not programmed, a default length of 360 degrees is selected automatically.
1.) Simultaneously press and hold
GATE
and
MODE
buttons until “Advanced 2” appears. The display will show
the velocity factor (factory default to 0.66):
2.) Set VF to the desired value.
GATE
increases VF,
MODE
decreases VF. When the desired VF is reached
simultaneously press and hold the
GATE
and
MODE
buttons until “Distance to Fault” appears.
Note: If you know the true electrical length in degrees, set velocity factor to VF=1.0 and enter the
electrical length in degrees as indicated in step 5.
3.) Press and release the
MODE
button. The display will flash “Line Length in Degrees”.
After a moment, a display appears showing: