MFJ-269C Instruction Manual LF/HF/VHF/UHF SWR Analyzer
27
VELOCITY FACTOR?
VF= 0.70
Note:
If you know the true electrical length in feet, set
Vf
to VF=1.0 and enter the
Electrical Length
in
feet.
3.
Press
Mode,
and a display showing
Length in Feet
and
Length in Degrees
will appear.
14.315 MHz
L=100.0 ft= 73
o
4.
The display now shows the
Electrical Degrees
for the entered line length (default is 100 feet) at the
Vf
you entered in step 1. By adjusting the
Frequency
and
Tune
controls, the analyzer will recalculate the
results for any frequency you wish (see sample screens below):
5.
Pressing
Mode
again takes the display to section 5.5.3.2. Pressing
Gate
takes the display to a
Line
Length
adjustment function.
Line length ?
l = 100.0 ft
6.
To
increase
line length, press the
Gate
. To
decrease
line length, 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 = 67.2. ft
7.
Pressing
Mode
switches the display to
Length in Feet
for the degrees programmed in at the selected
Vf
.
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 (see section 5.5.1 for HF/VHF).