Tektronix 1502C User Manual

Page of 126
Operator Tutorial
1502C MTDR User Manual
2–9
50 
W impedance plus 9.5 W series resistance. You can check this by putting a
known reference on the end of the cable and measuring its impedance with
ohms-at-cursor. The difference between the actual reading and the expected
reference reading is the series resistance.
O
F
F
O
F
F
O
F
F
O
N
ac
59.5
W
408.000 ft
Ohms-at-Cursor
Readout
Figure 2–10: Ohms-at-Cursor
7. Turn the 
n
o
POSITION control to set the cursor near the beginning of the
cable. In this example, the ohms-at-cursor reading is 50.9 
W at 17.880 feet.
There is less loss at the beginning of the cable because there is less series
resistance.
O
F
F
O
F
F
O
F
F
O
N
ac
50.9
W
17.880 ft
Figure 2–11: Ohms-at-Cursor Near Beginning of Cable
8. Turn the 
n
o
POSITION control clockwise to set the cursor past the reflected
pulse. Note that the ohms-at-cursor reading is 
≥1 kW.