MFJ-269 Instruction Manual HF/VHF/UHF SWR Analyzer
27
LOCKED FOR UHF OPERATION ONLY WHEN UHF OPERATION IS DESIRED
AND ONLY AFTER THE UNIT IS POWERED UP. FOR INFORMATION ON
UHF OPERATION, SEE SECTION 3.4
1.)
The first menu that appears is:
The
GATE
button increases the Vf, the
MODE
button decreases the Vf. Set the Vf to the known Vf of the
transmission line. This setting will affect the
physical length
of the line (in feet) displayed later. If you want to
know the
electrical length
in feet, set Vf to unity (1.00).
NOTE: Incorrect Vf settings do not cause errors in electrical measurements, such as
“Length in
Degrees”
. Incorrect Vf settings will cause an error in physical length calculations, such as
“Dist. to Fault”
.
2.)
After setting the Vf, press
GATE
and
MODE
simultaneously to lock-in the desired Vf. The display will
indicate:
and after a few seconds change to:
1 5 .8 1 4 M H z 1 st
D TF X s= 5 1
This display prompts you to find a frequency of lowest reading on the
IMPEDANCE
meter that coincides with
Xs as close to Xs=0 as possible. When you find that frequency, press the
GATE
button firmly until the flashing
“1st”
on the display stops flashing. Release the
GATE
button quickly.
3.)
The display now indicates the first frequency data point and the blinking
“1st”
will change to a blinking
“2nd”
:
2 1 .3 2 4 M H z 2 n d
D TF X s= 0
4.)
Slowly tune the analyzer higher or lower in frequency until the Impedance meter indicates the very
next
low
IMPEDANCE
meter reading, and reactance (
Xs=
) is zero or the lowest possible value near zero.
6 8 .5 1 1 M H z 2 n d
D TF X s= 1
5.)
Press the
“GATE”
button again, and the display will indicate distance in feet: