HP 85106D, Manual

Page: 79 / 244

2-34 HP 85106D mm-Wave System
Operation
Common Problems and Their Solutions
Common Problems and Their Solutions
While preparing for mm-wave measurements you may encounter some of
the following problems. Some recommended points to check are listed
below:
Problem
CAUTION: NO IF FOUND
displayed (or very low detected signal levels)
Possible Causes and Solutions
If a microwave test set is connected as well, verify that the test set ACTIVE
LED is off. If it is on, then toggle the test set address.
1. Press [
SYSTEM
] {
HP-IB ADDRESS
} {
TEST SET
}.
2. Enter [
20
] [
x1
]
3. Enter [
21
] [
x1
]
If an RF Switch is also used, the SWITCH 0 LED should be on during
mm-wave operation and off during microwave operation.
Problem
Data is grossly incorrect after calibration.
Possible Causes and Solutions
{
FACTORY PRESET
} was pressed and the {
SET Z0
} function (under the CAL
menu) was reset to 50 ohms during a waveguide calibration. RECALL the
correct mm-wave instrument state (Z
o
=1), then calibrate again.