Operator Tutorial
A Longer Cable
2–6
Longer cables might not fit in the display. Let's demonstrate that with a longer cable.
Obtain a known length of cable, preferably 50 . For this example, we are using a
coaxial cable approximately 455 feet long. Your cable length will probably differ,
but the following test procedure remains fundamentally correct for any cable length
up to 50,000 feet.
1. Set the 1503C front-panel controls:
CABLE
IMPEDANCE
NOISE FILTER
VERT SCALE
DIST/DIV
Vp
PULSE WIDTH
2. With these settings, we can view the entire cable. By placing the cursor at the
rise of the reflected pulse, we can see this particular cable is 456.00 ft.
ac
O
N
O
F
F
O
F
F
O
F
F
Figure 2–8: Cursor on End of Longer Cable
3. By decreasing the DIST/DIV control, the cable can be more closely inspected
at the point of the cursor. Decrease the DIST/DIV to 10 ft/div. This has expanded
the cable across the display.
4. Turn the
POSITION control counterclockwise. Note that the distance
window changes as you scroll down the cable. In reality, you are electrically
inspecting the cable, foot by foot.
available longer cable
50
1 avg
10 dB
100 ft (25 m)
appropriate setting for your cable
Auto (clockwise)
456.00 ft
auto
1503C MTDR User Manual
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