Tektronix 1503C, User Manual, Page: 27 / 128

Operating Instructions
1503C MTDR User Manual
1–11
50
W 75 W 93 W 125 W
RG-4 RG-6/U RG-7/U RG-23/U
RG-8/U RG-11/U RG-22/U RG-63/U
RG-9/U RG-12/U RG-62/U RG-79/U
RG-58/U RG-13/U RG-71/U RG-89/U
RG-62/U RG-59/U RG-111/U Flat Lead
RG-81 RG-124/U Twisted Pair Twisted Pair
RG-93 RG-140/U
RG-142B/U RG-179/U
RG-225/U 75 Video
RG-303B/U
RG-316/U
RG-393/U
Vertebrae Helix
1. Obtain a known length of cable of the exact type you wish to test. Attach the
cable to the CABLE connector on the front panel.
2. Pull POWER on.
3. Turn the DIST/DIV to an appropriate setting (e.g., if trying to find the Vp of a
three-foot cable, turn the DIST/DIV to 1 ft/div).
4. Turn the
n o
POSITION control until the distance reading is the same as the
known length of this cable.
5. Turn the Vp controls until the cursor is resting on the rising portion of the
reflected pulse. The Vp controls of the instrument are now set to the Vp of the
cable.
The following three illustrations show settings too low, too high, and correct for a
sample three-foot cable.
O
F
F
O
F
F
O
F
F
O
N
ac 3.00 ft
Figure 1–5: Vp Set at .30, Cursor Beyond Reflected Pulse (Setting Too Low)
Impedance of Various
Cable Types
Finding an Unknown Vp