Keysight Technologies 85131C Service manual

Keysight Technologies
85131C/D/G NMD-3.5 mm -f-
to 3.5 mm Semi-Rigid
Test Port Return Cables
Operating and
Service Manual

85131C/D/G i

ii 85131C/D/G
Documentation Warranty
THE MATERIAL CONTAINED IN THIS DOCUMENT IS PROVIDED "AS IS," AND IS
SUBJECT TO BEING CHANGED, WITHOUT NOTICE, IN FUTURE EDITIONS. FURTHER,
TO THE MAXIMUM EXTENT PERMITTED BY APPLICABLE LAW, KEYSIGHT DISCLAIMS
ALL WARRANTIES, EITHER EXPRESS OR IMPLIED WITH REGARD TO THIS MANUAL
AND ANY INFORMATION CONTAINED HEREIN, INCLUDING BUT NOT LIMITED TO THE
IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
PURPOSE. KEYSIGHT SHALL NOT BE LIABLE FOR ERRORS OR FOR INCIDENTAL OR
CONSEQUENTIAL DAMAGES IN CONNECTION WITH THE FURNISHING, USE, OR
PERFORMANCE OF THIS DOCUMENT OR ANY INFORMATION CONTAINED HEREIN.
SHOULD KEYSIGHT AND THE USER HAVE A SEPARATE WRITTEN AGREEMENT WITH
WARRANTY TERMS COVERING THE MATERIAL IN THIS DOCUMENT THAT CONFLICT
WITH THESE TERMS, THE WARRANTY TERMS IN THE SEPARATE AGREEMENT WILL
CONTROL.
DFARS/Restricted Rights Notice
If software is for use in the performance of a U.S. Government prime contract or subcontract,
Software is delivered and licensed as “Commercial computer software” as defined in DFAR
252.227-7014 (June 1995), or as a “commercial item” as defined in FAR 2.101(a) or as
“Restricted computer software” as defined in FAR 52.227-19 (June 1987) or any equivalent
agency regulation or contract clause. Use, duplication or disclosure of Software is subject to
Keysight Technologies’ standard commercial license terms, and non-DOD Departments and
Agencies of the U.S. Government will receive no greater than Restricted Rights as defined in
FAR 52.227-19(c)(1-2) (June 1987). U.S. Government users will receive no greater than
Limited Rights as defined in FAR 52.227-14 (June 1987) or DFAR 252.227-7015 (b)(2)
(November 1995), as applicable in any technical data.

85131C/D/G iii
Printing Copies of Documentation from the Web
To print copies of documentation from the Web, download the PDF file from the Keysight web
site:
•Gotohttp://www.keysight.com.
• Enter the document’s part number (located on the title page) in the Search box.
• Click Search.
• Click on the hyperlink for the document.
• Click the printer icon located in the tool bar.

Contents
85131C/D/G iv
1. General Information
The Cable Sets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-2
85131C . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-2
85131D . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-2
85131G. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-2
Connector Designators. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-2
Clarifying the Terminology of a Connector Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-3
Incoming Inspection. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-3
Preventive Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-4
Replaceable Parts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-4
2. Specifications
Environmental Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-2
Electrical Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-2
Supplemental Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-3
Center Conductor Pin Depth . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-3
3. Use, Maintenance, and Care of the Cables
Electrostatic Discharge . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-2
Visual Inspection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-3
Look for Obvious Defects and Damage First . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-3
Inspect the Mating Plane Surfaces. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-3
Precision Slotless Connectors (3.5 mm) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-4
Cleaning Connectors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-5
Gaging Connectors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-7
Connector Gage Accuracy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-7
When to Gage Connectors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-7
Gaging Procedures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-8
Making Connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-10
How to Make a Connection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-10
How to Separate a Connection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-12
Handling and Storage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-12
Avoiding Cable Movement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-13
4. Replaceable Parts
Ordering Replaceable Parts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-2
Ordering One Cable in a Cable Set . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-2
Returning a Cable or Cable Set to Keysight . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-3
Contacting Keysight . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-3
Information About Network Analyzers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-3
A. Connector Care Quick Reference
Principles of Microwave Connector Care . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .A-2

Contents
85131C/D/G
v

1General Information

1-2 85131C/D/G
General Information
The Cable Sets
The Cable Sets
The Keysight 85131C/D/G semi-rigid cable sets are designed for use with Keysight network
analyzers that have male NMD-3.5 mm test ports.
85131C
The 85131C set contains a single cable. Use it when a DUT is connected, with the appropriate
adapter, directly to the test set test port. See Figure 1-1.
85131D
The 85131D set contains two cables. Each is shorter than the 85131C cable. Use the 85131D
cables when a DUT is connected between cable ends. See Figure 1-1.
Figure 1-1 Cable Configurations
85131G
The 85131G set contains a single cable – the -f- to -m- cable from the 85131D cable set. It is
shorter than the 85131C single cable. See Figure 1-1.
Connector Designators
NMD Connectors
NMD denotes a connector that has larger than standard coupling threads for greater stability.
NMD connectors are used on test cables, test ports, test port adapters, and test port cables.
Female NMD test port connectors are used on the test set end of adapters and cables, and
cannot be connected to standard male connectors.
Male NMD connectors are used on test sets (as test ports), and on the DUT end of adapters
and cables. Male connectors have both the larger threads (for use with test port adapters) and
standard threads (for direct coupling to a DUT).

85131C/D/G 1-3
General Information
Incoming Inspection
PSC Connectors
PSC denotes a precision slotless connector. Precision slotless connectors are metrology grade
connectors that have better electrical performance, better repeatability, and are more durable
than slotted connectors.
Clarifying the Terminology of a Connector Interface
In this document and in the prompts of the PNA calibration wizard, the gender of cable
connectors and adapters is referred to in terms of the center conductor. For example, a
connector or device designated as 1.85 mm –f– has a 1.85 mm female center conductor.
8510-series, 872x, and 875x ONLY: In contrast, during a measurement calibration, the
network analyzer softkey menus label a 1.85 mm calibration device with reference to the sex of
the analyzer’s test port connector—not the calibration device connector. For example, the label
SHORT(F) refers to the short that is to be connected to the female test port. This will be a male
short from the calibration kit.
A connector gage is referred to in terms of the connector that it measures. For instance, a male
connector gage has a female connector on the gage so that it can measure male devices.
Incoming Inspection
Verify that the shipment is complete by referring to Table 4-1 on page 4-4.
If the case or any device appears damaged, or if the shipment is incomplete, notify Keysight.
See “Contacting Keysight” on page 4-3. Keysight will arrange for repair or replacement of
incomplete or damaged shipments without waiting for a settlement from the transportation
company.
When you send the cable set to Keysight, include the following information:
• your company name and address
• the name of a technical contact person within your company, and the person’s complete
phone number
• the model number and serial number of the cable set
Table 1-1 Clarifying the Sex of Connectors: Examples
Terminology Meaning
Short –f– Female short (female center conductor)
Short (f) Male short (male center conductor) to be connected to female port

1-4 85131C/D/G
General Information
Preventive Maintenance
• the part number and serial number of the device
• the type of service required
•adetailed description of the problem
Preventive Maintenance
The best techniques for maintaining the integrity of the cables include:
• routine visual inspection
• cleaning
• proper gaging
• proper connection techniques
• proper storage
All of the above are described in Chapter 3. Failure to detect and remove dirt or metallic
particles on a mating plane surface can degrade repeatability and accuracy and can damage
any connector mated to it. Improper connections, resulting from center conductor values being
out of limits (see Table 2-3 on page 2-4), or from bad connections, can also damage cable
connectors.
Replaceable Parts
See Table 4-1 on page 4-4 for a complete list of cable set contents and their associated part
numbers (you can order a single cable rather than the entire cable set), and for recommended
items not included with the cable set. Refer to “Contacting Keysight” on page 4-3 for
information about communicating with Keysight.

2Specifications

2-2 85131C/D/G
Specifications
Environmental Requirements
Environmental Requirements
Electrical Specifications
Table 2-1 Environmental Requirements
Parameter Limits
Operating temperature +20 °C to +26 °C (+68 °F to +79 °F)
Storage temperature −40 °C to +75 °C (−40 °F to +167 °F)
Altitude
Operation < 4,500 meters (≈15,000 feet)
Storage < 4,500 meters (≈15,000 feet)
Relative humidity Always non-condensing
Operation Up to 80% at 30°C
Storage Up to 95% at 40°C
Table 2-2 Electrical Specifications
Cable SWR Return Loss
(dB)
Insertion Loss
(dB)a
a. f = frequency in GHz.
Frequency Range
(GHz)
85131C ≤1.38 ≥15.94 ≤0.43 √f + 0.3 DC to 26.5
85131D ≤0.30 √f + 0.2
85131G

85131C/D/G 2-3
Specifications
Supplemental Characteristics
Supplemental Characteristics
Table 2-3 lists supplemental performance characteristics. These are not specifications, but are
intended to provide additional information useful to your application. Supplemental
characteristics are typical (but not warranted) performance parameters.
Center Conductor Pin Depth
Center conductor pin depth is the distance the center conductor mating plane differs from being
flush with the outer conductor mating plane. See Figure 2-1 The pin depth of a center
conductor can be in one of two states: either protruding or recessed.
Protrusion is the condition in which the center conductor extends beyond the outer conductor
mating plane. This condition will indicate a positive value on the connector gage.
Recession is the condition in which the center conductor is set back from the outer conductor
mating plane. This condition will indicate a negative value on the connector gage.
Table 2-3 Supplemental Characteristics (1 of 3)
Cable Cable Length Approximate
Electrical
Length
Magnitude and
Phase Stability
With a 90°
Benda,b
a. (f) = frequency in GHz.
b. With a 90°, four-inch bend radius.
Magnitude
and Phase
Stability After
Three
Bending/
Straightening
Cyclesa, b
Minimum
Recommend
ed Bend
Radius
cm in m in cm in
85131C 81.0 32.0 1.150 45.264 <0.06 dB
Change
<0.16°(f) + 0.5°
<0.03 dB
Change
<0.13°(f) +
0.3°
10.2 4
85131D 53.0 21.0 0.74 29.126
85131G
Table 2-3 Supplemental Characteristics (2 of 3)
Cable Set Number
of
Cables
Test Set End
Connector Type
DUT End Connector Type
85131C 1 NMD-3.5 mm -f- PSC-3.5 mm -f-
85131D 2 NMD-3.5 mm -f- 3.5 mm -m- and
PSC-3.5 mm -f-
85134G 1 NMD-3.5 mm -f- 3.5 mm -m-

2-4 85131C/D/G
Specifications
Supplemental Characteristics
Figure 2-1 Connector Center-Conductor Pin Depth
Table 2-3 Supplemental Characteristics (3 of 3)
Center-Conductor Pin Depth
Precision
Connector Allowable Recessiona
a. Center conductor shoulder behind outer conductor mating plane.
Allowable Protrusion
mm in mm in
NMD-3.5 mm -f- -0.005 to -0.056 -0.0002 to -0.0022 0.0000 0.0000
PSC-3.5 mm -f- -0.0025 to -0.013 -0.0001 to -0.0005
3.5 mm -m-

3Use, Maintenance, and Care of the Cables

3-2 85131C/D/G
Use, Maintenance, and Care of the Cables
Electrostatic Discharge
Electrostatic Discharge
Protection against ESD (electrostatic discharge) is essential while connecting, inspecting, or
cleaning connectors attached to a static-sensitive circuit (such as those found in test sets).
Static electricity can build up on your body and can easily damage sensitive internal circuit
elements when discharged. Static discharges too small to be felt can cause permanent
damage. Devices such as calibration components and devices under test (DUTs), can also
carry an electrostatic charge. To prevent damage to the test set, components, and devices:
•always wear a grounded wrist strap having a 1 MΩresistor in series with it when handling
components and devices or when making connections to the test set.
•always use a grounded, conductive table mat while making connections.
•always wear a heel strap when working in an area with a conductive floor. If you are
uncertain about the conductivity of your floor, wear a heel strap.
•always ground yourself before you clean, inspect, or make a connection to a static-sensitive
device or test port. You can, for example, grasp the grounded outer shell of the test port or
cable connector briefly.
•always ground the center conductor of a test cable before making a connection to the
analyzer test port or other static-sensitive device. This can be done as follows:
1. Connect a short (from your calibration kit) to one end of the cable to short the center
conductor to the outer conductor.
2. While wearing a grounded wrist strap, grasp the outer shell of the cable connector.
3. Connect the other end of the cable to the test port.
4. Remove the short from the cable.
Refer to Chapter 4 for part numbers and instructions for ordering ESD protection devices.
Figure 3-1. ESD Protection Setup

85131C/D/G 3-3
Use, Maintenance, and Care of the Cables
Visual Inspection
Visual Inspection
Visual inspection and, if necessary, cleaning should be done every time a connection is made.
Metal particles from the connector threads may fall onto the mating plane surface of the
connector when it is disconnected. One connection made with a dirty or damaged connector
can damage both connectors beyond repair.
Magnification is helpful when inspecting connectors, but it is not required and may actually be
misleading. Defects and damage that cannot be seen without magnification generally have no
effect on electrical or mechanical performance. Magnification is of great use in analyzing the
nature and cause of the damage and in cleaning connectors, but it is not required for
inspection. Use the following guidelines when evaluating the integrity of a connector.
Look for Obvious Defects and Damage First
Examine the connector first for obvious defects and damage: badly worn plating on the
connector interface, deformed threads, or bent, broken, or misaligned center conductors.
Connector nuts should move smoothly and be free of burrs, loose metal particles, and rough
spots.
What Causes Connector Wear?
Connector wear is caused by connecting and disconnecting the cable. The more use a
connector gets, the faster it wears and degrades. The wear is greatly accelerated when
connectors are not kept clean, or are connected incorrectly.
Connector wear eventually degrades performance of the cable. Replace cables with worn
connectors.
The test port connectors on the network analyzer test set may have many connections each
day, and are therefore also subject to wear. It is recommended that an adapter be used as a
test port saver to minimize the wear on the test set’s test port connectors.
Inspect the Mating Plane Surfaces
Flat contact between the connectors at all points on their mating plane surfaces is required for
a good connection. Look especially for deep scratches or dents, and for dirt and metal particles
on the connector mating plane surfaces. Also look for signs of damage due to excessive or
uneven wear or misalignment.
Light burnishing of the mating plane surfaces is normal, and is evident as light scratches or
shallow circular marks distributed more or less uniformly over the mating plane surface. Other
small defects and cosmetic imperfections are also normal. None of these affect electrical or
mechanical performance.
If a connector shows deep scratches or dents, particles clinging to the mating plane surfaces,
or uneven wear, clean and inspect it again. Cables with damaged connectors should be
repaired or discarded. Determine the cause of damage before connecting a new, undamaged
connector in the same configuration.

3-4 85131C/D/G
Use, Maintenance, and Care of the Cables
Precision Slotless Connectors (3.5 mm)
Precision Slotless Connectors (3.5 mm)
The female 3.5 mm connectors in the cable sets are metrology-grade, precision slotless
connectors (PSC). Precision slotless connectors are used to improve accuracy. A characteristic
of metrology-grade connectors is directly traceability to national measurement standards
through their well-defined mechanical dimensions. With PSCs on test ports and standards, the
accuracy achieved when measuring at 50 dB return loss levels is comparable to using
conventional slotted connectors measuring devices having only 30 dB return loss. This
represents an accuracy improvement of about 10 times.
Conventional female center conductors are slotted and, when mated, are flared by the male
pin. Because physical dimensions determine connector impedance, this change in physical
dimension affects electrical performance, making it very difficult to perform precision
measurements with conventional slotted connectors.
The precision slotless connector was developed to eliminate this problem. The PSC has a
center conductor with a solid cylindrical shell, the outside diameter of which does not change
when mated. Instead, the center conductor has an internal contact that flexes to accept the
male pin.

85131C/D/G 3-5
Use, Maintenance, and Care of the Cables
Cleaning Connectors
Cleaning Connectors
Clean connectors are essential for ensuring the integrity of RF and microwave coaxial
connections.
1. Use Compressed Air or Nitrogen
WARNING Always use protective eyewear when using compressed air or nitrogen.
Use compressed air (or nitrogen) to loosen particles on the connector mating plane
surfaces.
You can use any source of clean, dry, low-pressure compressed air or nitrogen that has an
effective oil-vapor filter and liquid condensation trap placed just before the outlet hose.
Ground the hose nozzle to prevent electrostatic discharge, and set the air pressure to less
than 414 kPa (60 psi) to control the velocity of the air stream. High-velocity streams of
compressed air can cause electrostatic effects when directed into a connector. These
electrostatic effects can damage the device. Refer to “Electrostatic Discharge” earlier in this
chapter for additional information.
2. Clean the Connector Threads
WARNING Keep isopropyl alcohol away from heat, sparks, and flame. Store in a tightly
closed container. It is extremely flammable. In case of fire, use alcohol
foam, dry chemical, or carbon dioxide; water may be ineffective.
Use isopropyl alcohol with adequate ventilation and avoid contact with eyes, skin, and
clothing. It causes skin irritation, may cause eye damage, and is harmful if swallowed or
inhaled. It may be harmful if absorbed through the skin. Wash thoroughly after handling.
In case of spill, soak up with sand or earth. Flush spill area with water.
Dispose of isopropyl alcohol in accordance with all applicable federal, state, and local
environmental regulations.
Use a lint-free swab or cleaning cloth moistened with isopropyl alcohol to remove any dirt or
stubborn contaminants on a connector that cannot be removed with compressed air or
nitrogen. Refer to Table 4-1 on page 4-4 for part numbers for isopropyl alcohol and cleaning
swabs.
a. Apply a small amount of isopropyl alcohol to a lint-free cleaning swab.
b. Clean the connector threads.
c. Let the alcohol evaporate, then blow the threads dry with a gentle stream of clean,
low-pressure compressed air or nitrogen. Always completely dry a connector before you
reassemble or use it.

3-6 85131C/D/G
Use, Maintenance, and Care of the Cables
Cleaning Connectors
3. Clean the Mating Plane Surfaces
a. Apply a small amount of isopropyl alcohol to a lint-free cleaning swab.
b. Clean the center and outer conductor mating plane surfaces. Refer to Figure 2-1 on
page 2-4. When cleaning a female connector, avoid snagging the swab on the center
conductor contact fingers by using short strokes.
c. Let the alcohol evaporate, then blow the connector dry with a gentle stream of clean,
low-pressure compressed air or nitrogen. Always completely dry a connector before you
reassemble or use it.
4. Reinspect
Inspect the connector again to make sure that no particles or residue are present.