Operator Tutorial
1502C MTDR User Manual 2–15
This control is nearly the same as HORZ SET REF except it sets the vertical
zero reference. It would be helpful to read the section of VERT SET REF in the
Operating Instructions chapter to give you some technical background.
The VERT SET REF function allows manual control of the vertical calibration
of the 1502C. This can be used to compensate for cable loss or to increase the
resolution of the millirho scale. The following example shows how to compen-
sate for cable loss.
The reflection from an open or a short at the far end of a long cable is often less
than two divisions high at 500 mr/div. This is because of the energy lost in the
cable. Here is how to correct for this loss and be able to make accurate measure-
ments at the far end of the cable.
1. Connect the test cable.
2. Create a short across the far end of the cable.
3. Turn the NOISE FILTER all the way counterclockwise to VERT SET REF.
A prompt will appear and the LCD will indicate set ref.
O
F
F
O
F
F
O
F
F
O
N
ac 0.000 ft
Figure 2–20: Display with 3-ft Cable and NOISE FILTER turned to VERT SET REF
4. Adjust the VERT SCALE control until the reflection from the short is two
divisions high.
5. Push STORE.
VERT SET REF