Tektronix 1502C User Manual page 60

1502C MTDR User Manual
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.
ac
O
N
O
F
F
O
F
F
O
F
F
Figure 2–10: Ohms-at-Cursor
7. Turn the 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.
ac
O
N
O
F
F
O
F
F
O
F
F
Figure 2–11: Ohms-at-Cursor Near Beginning of Cable
8. Turn the POSITION control clockwise to set the cursor past the reflected
pulse. Note that the ohms-at-cursor reading is ≥1 kW.
Operator Tutorial
408.000 ft
Ohms-at-Cursor
59.5 W
Readout
17.880 ft
50.9 W
2–9