Keysight 8490D/G, 8491A/B,
8493A/B/C Coaxial Fixed
Attenuators
Keysight 11581A, 11582A,
11583C Attenuator Sets
Operating and
Service Manual
Notices
CAUTION
WARNING
Copyright Notice
© Keysight Technologies 2014 - 2019
No part of this manual may be repro-
duced in any form or by any means
(including electronic storage and
retrieval or translation into a foreign
language) without prior agreement and
written consent from Keysight Technologies as governed by United States and
international copyright laws.
Manual Part Number
08491-90077
Edition
Edition 6, June 26, 2019
Printed in:
Printed in Malaysia
Published by:
Keysight Technologies
Bayan Lepas Free Industrial Zone,
11900 Penang, Malaysia
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The hard ware and/or software
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Web. Go to http://www.keysight.com/
go/conformity. You can then search by
product number to find the latest Declaration of Conformity.
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The Software is “commercial computer
software,” as defined by Federal Acquisition Regulation (“FAR”) 2.101. Pursuant to FAR 12.212 and 27.405-3 and
Department of Defense FAR Supplement (“DFARS”) 227.7202, the U.S.
government acquires commercial computer software under the same terms
by which the software is customarily
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Keysight provides the Software to U.S.
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urnish technical informat
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r
elated to commercial computer software or commercial computer software
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ovided to the public; or (2) Relinquish
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icitly required from all providers of
expl
commercial computer software pursuant to the FAR and the DFARS and ar
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r
espect to any technical data as
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12.211 and
227.7102, the U.S.
a
cquires no greater than Limited Rights
as defined in FAR 27.401 or DF
227.7103-5 (c), as
echnical data.
t
27.404.2 and DFAR
governme
applicable in
ion
y
No
at
e
e
With
R
S
nt
AR
any
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
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TO THIS MANUAL AND ANY INFORMATION CONTAINED HEREIN, INCLUDING BUT NOT LIMITED TO THE
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Safety Information
A CAUTION notice denotes a hazard. It
calls attention to an operating procedure, practice, or the like that, if not
correctly performed or adhered to,
could result in damage to the product
or loss of important data. Do not proceed beyond a CAUTION notice until
the indicated conditions are fully
understood and met.
A WARNING notice denotes a hazard. It
calls attention to an operating procedure, practice, or the like that, if not
correctly performed or adhered to,
could result in personal injury or death.
Do not proceed beyond a WARNING
notice until the indicated conditions are
fully understood and met.
2 Keysight 849x and 1158x Operating and Service Manual
Waste Electrical and Electronic Equipment (WEEE) Directive
This instrument complies with the WEEE Directive marking requirement. This
affixed product label indicates that you must not discard this electrical or
electronic product in domestic household waste.
Product category:
With reference to the equipment types in the WEEE directive Annex 1, this
instrument is classified as a “Monitoring and Control Instrument” product.
The affixed product label is as shown below.
Do not dispose in domestic household waste.
To return this unwanted instrument, contact your nearest Keysight Service Center,
or visit http://about.keysight.com/en/companyinfo/environment/takeback.shtml
for more information.
Sales and Technical Support
To contact Keysight for sales and technical support, refer to the support links on
the following Keysight websites:
– www.keysight.com/find/attenuators
(product-specific information and support, software and
documentation updates)
– www.keysight.com/find/assist
(worldwide contact information for repair and service)
Keysight 849x and 1158x Operating and Service Manual 3
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4 Keysight 849x and 1158x Operating and Service Manual
Table of Contents
Waste Electrical and Electronic Equipment (WEEE) Directive . . . . . . . .3
Product category: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3
Sales and Technical Support . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3
List of Figures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7
List of Tables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
General Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11
Attenuator overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11
Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .12
Optional calibration data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .12
Attenuator sets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .12
Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .13
Environmental Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .20
Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
Initial inspection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .21
Returning attenuators under warranty . . . . . . . . . . . . . . . . . . . . . . .21
Operating Instruction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .22
Operator’s check . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .22
Using oscillator and SWR meter . . . . . . . . . . . . . . . . . . . . . . . . . . . .22
Using network analyzer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .24
Making Connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .25
8490D/G . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .25
8491A/B . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .26
8493A/B . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .27
8493C . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .28
Performance Test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .29
Service Instructions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .30
Repair . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .30
Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
Keysight 849x and 1158x Operating and Service Manual 5
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6 Keysight 849x and 1158x Operating and Service Manual
List of Figures
Figure 1 Equipment setup using oscillator and SWR meter . . .22
Figure 2 Equipment setup using network analyzer . . . . . . . . . .24
Figure 3 2.4-mm/1.85mm connector diagram . . . . . . . . . . . . .25
Figure 4 Type-N connector diagram . . . . . . . . . . . . . . . . . . . . .26
Figure 5 SMA connector diagram . . . . . . . . . . . . . . . . . . . . . . .27
Figure 6 3.5-mm connector diagram . . . . . . . . . . . . . . . . . . . . .28
Keysight 849x and 1158x Operating and Service Manual 7
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8 Keysight 849x and 1158x Operating and Service Manual
List of Tables
Table 1 List of coaxial fixed attenuators . . . . . . . . . . . . . . . . . .11
Table 2 List of attenuator boxed sets . . . . . . . . . . . . . . . . . . . .12
Table 3 Specifications for 8490D coaxial fixed attenuator . . . . 13
Table 4 Specifications for 8490G coaxial fixed attenuator . . . . 14
Table 5 Specifications for 8491A and 8493A coaxial fixed
attenuators . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .15
Table 6 Specifications for 8491B and 8493B coaxial fixed
attenuators . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .16
Table 7 Specifications for 8493C coaxial fixed attenuator . . . .18
Table 8 Accuracy of insertion loss measurements (S
Table 9 Accuracy of reflection coefficient measurements (S
) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
S
22
, S12). .19
21
,
11
Table 10 849x coaxial fixed attenuator and 1158x attenuator sets
environmental specifications . . . . . . . . . . . . . . . . .20
Table 11 SWR verification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .23
Keysight 849x and 1158x Operating and Service Manual 9
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10 Keysight 849x and 1158x Operating and Service Manual
General Information
Attenuator overview
The 8490D/G, 8491A/B, and 8493A/B/C are small, light-weight, low-power,
50-ohm coaxial fixed attenuators.
The attenuators cover broad frequency ranges and choice of connector types.
Each model comes with Options to accommodate various attenuation values as
shown in Table 1.
Table 1 List of coaxial fixed attenuators
Model Option Frequency range Connector type
8490D 003, 006, 010, 020, 030, 040 DC to 50 GHz 2.4 mm (m), (f)
8490G 003, 006, 010, 020, 030, 040 DC to 67 GHz 1.85 mm (m), (f)
8491A
003, 006, 010, 020, 030, 040,
050, 060
General Information 1
DC to 12.4 GHz Type N (m), (f)
8491B
8493A 003, 006, 010, 020, 030 DC to 12.4 GHz SMA 3 mm (m), (f)
8493B 003, 006, 010, 020, 030 DC to 18 GHz SMA 3 mm (m), (f)
8493C 003, 006, 010, 020, 030, 040 DC to 26.5 GHz 3.5 mm (m), (f )
003, 006, 010, 020, 030, 040,
050, 060
DC to 18 GHz Type N (m), (f)
The Option number indicates the attenuation value. For example, Option 003
indicates 3 dB attenuation, Option 010 indicates 10 dB attenuation, and so on.
Keysight 849x and 1158x Operating and Service Manual 11
1 General Information
Features
– Ruggedness, reliability, and small size make these attenuators useful both on
the bench and in systems applications.
– Accuracy and low SWRs make the attenuators well suited for extending the
range of sensitive power meters for higher power measurements and
applications such as calibration standards and RF substitution measurements.
– Each attenuator is tested with a vector network analyzer for attenuation, and a
plot of actual attenuation values is printed on the label attached to the body of
the attenuator (except for the 8490D/G and 8493C).
Optional calibration data
Option UK6 calibration data, which is generated by a network analyzer, provides a
tabulated list of attenuations and reflection coefficients in which the number of
frequency points provided depends on the model number and frequency range.
Option UK6 calibration data is available when attenuators are first purchased and
recalibrations are available through Keysight Technologies Service Centers.
Attenuator sets
The 11581A, 11582A, and 11583C are boxed sets of four coaxial fixed attenuators
of 3, 6, 10, and 20 dB as shown in Table 2.
Each attenuator set comes with a printed calibration report that gives the actual
attenuation and reflection coefficient of each port at frequencies from 100 MHz to
12.4 GHz for 11581A, 100 MHz to 18 GHz for 11582A, and 100 MHz to 26.5 GHz
for 11583C, at increments from 100 to 500 MHz.
Tab le 2 List of attenuator boxed sets
Model Contents Frequency range
11581A 8491A (3, 6, 10, and 20 dB) DC to12.4 GHz
11582A 8491B (3, 6, 10, and 20 dB) DC to 18 GHz
11583C 8493 C (3, 6, 10, and 20 dB) DC to 26.5 GHz
12 Keysight 849x and 1158x Operating and Service Manual
Specifications
The specifications refer to the performance standards or limits against which the
coaxial fixed attenuators are tested.
Table 3 Specifications for 8490D coaxial fixed attenuator
Specifications 1
Minimum attenuation
in dB
[a]
Option
003 2.5 3.9 4.8
006 5.4 6.9 7.8
010 9.4 10.9 11.3
020 19.2 21.3 21.7
030 29.2 31.3 31.7
040 38.2 42.5 42.5
[a]
Option
003 1.15 1.25 1.45
006 1.15 1.25 1.45
010 1.15 1.25 1.45
020 1.15 1.25 1.45
030 1.15 1.25 1.45
040 1.08 1.15 1.25
Maximum input power 1 W avg, 100 W pk
Connectors (50 Ω)2.4 mm
Dimension (length)
Diameter 0.312 in. (8 mm)
DC to 50 GHz DC to 26.5 GHz 26.5 to 50 GHz
DC to 26.5 GHz 26.5 to 40 GHz 40 to 50 GHz
1.06 in. (27 mm) for Options 003, 006, 010, 020
1.14 in. (29 mm) for Options 030, 040
Maximum attenuation in dB
Maximum SWR
[a] Option numbers indicate the attenuation values. For example, Option 003 indicates 3 dB attenuation, Option 010
indicates 10 dB attenuation and so on.
Keysight 849x and 1158x Operating and Service Manual 13
1 Specifications
Tab le 4 Specifications for 8490G coaxial fixed attenuator
Option
Minimum
attenuation in dB
[a]
DC to 67 GHz DC to 26.5 GHz 26.5 to 50 GHz 50 to 67 GHz
Maximum attenuation in dB
003 2.5 3.9 4.4 4.8
006 5.4 6.9 7.4 7.8
010 9.4 10.9 11.1 11.3
020 19.2 21.3 21.5 21.7
030 29.2 31.3 31.5 31.7
040 38.0 42.5 42.5 42.5
Maximum SWR
Option
[a]
DC to 26.5 GHz 26.5 to 40 GHz 40 to 50 GHz
003 1.15 1.25 1.45
006 1.15 1.25 1.45
010 1.15 1.25 1.45
020 1.15 1.25 1.45
030 1.15 1.25 1.45
040 1.10 1.15 1.25
Maximum input
power
1 W avg, 100 W pk
Connectors (50 Ω) 1.85 mm
Dimension (length)
1.06 in. (27 mm) for Options 003, 006, 010, 020
1.10 in. (28 mm) for Options 030, 040
Diameter 0.312 in. (8 mm)
[a] Option numbers indicate the attenuation values. For example, Option 003 indicates 3 dB attenuation, Option 010
indicates 10 dB attenuation and so on.
14 Keysight 849x and 1158x Operating and Service Manual
Specifications 1
Table 5 Specifications for 8491A and 8493A coaxial fixed attenuators
Attenuation accuracy in dB
[a]
Option
003 ± 0.3
006 ± 0.3
010 ± 0.5
020 ± 0.5
030 ± 1.0
[b]
040
[b]
050
[b]
060
SWR
Option
[a]
DC to 8 GHz 8 to 12.4 GHz
003 1.25 1.35
DC to 12.4 GHz
± 1.5
± 1.5
± 2.0
006 1.2 1.3
010 1.2 1.3
020 1.2 1.3
030 1.2 1.3
040
050
060
[b]
[b]
[b]
1.2 1.3
1.2 1.3
1.2 1.3
Maximum input power 2 W avg, 100 W pk
Connectors (50 Ω)
8491A: Type N
[c]
8493A: SMA
[d]
Dimension (length) 8491A: 2-7/16 in. (67 mm) 8493A: 1-9/16 in. (40 mm)
Diameter 8491A: 13/16 in. (21 mm) 8493A: 1/2 in. (13 mm)
[a] Option numbers indicate the attenuation values. For example, Option 003 indicates 3 dB attenuation, Option 010
indicates 10 dB attenuation and so on.
Keysight 849x and 1158x Operating and Service Manual 15
1 Specifications
[b] Options 040, 050, and 060 are not available for 8493A.
[c] Mate with MIL-C-71 and MIL-C-39012 connectors.
[d] Miniature SMA type.
Tab le 6 Specifications for 8491B and 8493B coaxial fixed attenuators
Attenuation accuracy in dB
Option
[a]
DC to 12.4 GHz 12.4 to 18 GHz
003 ± 0.3 ± 0.3
006 ± 0.3 ± 0.4
010 ± 0.6 ± 0.6
020 ± 0.6 ± 1.0
030 ± 1.0 ± 1.0
040
050
060
[b]
[b]
[b]
± 1.5 ± 1.5
± 1.5 ± 1.5
± 2.0 ± 2.0
SWR
Option
[a]
DC to 8 GHz 8 to 12.4 GHz 12.4 to 18 GHz
003 1.25 1.35 1.5
006 1.2 1.3 1.5
010 1.2 1.3 1.5
020 1.2 1.3 1.5
030 1.2 1.3 1.5
040
050
060
[b]
[b]
[b]
1.2 1.3 1.5
1.2 1.3 1.5
1.2 1.3 1.5
Maximum input power 2 W avg, 100 W pk
Connectors (50 Ω)
8491B: Type N
[c]
8493B: SMA
[d]
16 Keysight 849x and 1158x Operating and Service Manual
Specifications 1
Dimension (length)
Diameter
[a] Option numbers indicate the attenuation values. For example, Option 003 indicates 3 dB attenuation, Option 010
indicates 10 dB attenuation and so on.
[b] Options 040, 050, and 060 are not available for 8493B.
[c] Mate with MIL-C-71 and MIL-C-39012 connectors.
[d] Miniature SMA type.
8491B: 2-7/16 in.
(67 mm)
8491B: 13/16 in.
(21 mm)
8493B: 1-9/16 in. (40 mm)
8493B: 1/2 in. (13 mm)
Keysight 849x and 1158x Operating and Service Manual 17
1 Specifications
Tab le 7 Specifications for 8493C coaxial fixed attenuator
Attenuation Accuracy in dB
Option
[a]
DC to 18 GHz 18 to 26.5 GHz
003 ± 0.5 ± 1.0
006 ± 0.6 ± 0.6
010 ± 0.3 ± 0.5
020 ± 0.5 ± 0.6
030 ± 0.7 ± 1.0
040 ± 1.0 ± 1.3
SWR
Option
[a]
DC to 8 GHz 8 to 12.4 GHz 12.4 to 26.5 GHz
003 1.10 1.15 1.25
006 1.10 1.15 1.27
010 1.10 1.15 1.25
020 1.10 1.15 1.25
030 1.10 1.15 1.25
040 1.10 1.15 1.25
Maximum input power 2 W avg, 100 W pk
Connectors (50 Ω)3.5 mm
Dimension (length)
1-15/16 in. (33.8 mm) for Options 003, 006, 010, 020
1-7/16 in. (36.8 mm) for Options 030, 040
Diameter 5/16 in. (8 mm)
[a] Option numbers indicate the attenuation values. For example, Option 003 indicates 3 dB attenuation, Option 010
indicates 10 dB attenuation and so on.
18 Keysight 849x and 1158x Operating and Service Manual
Specifications 1
Table 8 and Table 9 apply to the following boxed sets of four attenuators.
– The 11581A attenuator set contains a 3, 6, 10, and 20 dB 8491A.
– The 11582A attenuator set contains a 3, 6, 10, and 20 dB 8491B.
– The 11583C attenuator set contains a 3, 6, 10, and 20 dB 8493C.
Table 8 Accuracy of insertion loss measurements (S
Attenuation DC to 4 GHz 4 to 12 GHz 12 to 18 GHz
3 dB ± 0.01 dB ± 0.06 dB ± 0.11 dB
6 dB ± 0.01 dB ± 0.07 dB ± 0.11 dB
10 dB ± 0.01 dB ± 0.07 dB ± 0.12 dB
20 dB ± 0.01 dB ± 0.08 dB ± 0.13 dB
21
, S12)
Table 9 Accuracy of reflection coefficient measurements (S
Female Male
Model 4 to 12 GHz 12 to 18 GHz 4 to 12 GHz 12 to 18 GHz
11581A ± 0.006 dB - ± 0.006 dB -
11582A ± 0.006 dB ± 0.010 dB ± 0.006 dB ± 0.006 dB
11583C ± 0.007 dB ± 0.007 dB ± 0.007 dB ± 0.007 dB
11
, S22)
Keysight 849x and 1158x Operating and Service Manual 19
1 Environmental Specifications
Environmental Specifications
The 849x coaxial fixed attenuators and 1158x attenuator sets are designed to fully
comply with Keysight Technologies’ product operating environmental
specifications as shown Table 1 0.
Tab le 10 849x coaxial fixed attenuator and 1158x attenuator sets
environmental specifications
Temperature Humid ity Altitude
Operating 0 °C to +55 °C |95% relative at 40 °C |4,600 meters (15,000 feet)
Storage –55 °C to +85 °C |95% relative at 40 °C |15,300 meters (50,000 feet)
20 Keysight 849x and 1158x Operating and Service Manual
Installation
Initial inspection
Installation 1
1 Inspect the shipping container for damage. If the shipping container or
cushioning material is damaged, it should be kept until the contents of the
shipment have been checked for completeness and the instrument has been
checked both mechanically and electrically.
– Check for mechanical damage such as scratches or dents.
– Procedures for checking electrical performance are given under “Operator’s
check” on page 22 or “Performance Test” on page 29.
2 If the contents are incomplete, if there is mechanical damage or defect, or if
the instrument does not pass the electrical performance test, contact the
nearest Keysight Technologies Sales and Service office. Refer to the Service
and Support information in the front matter of this manual. Keysight
Technologies will arrange for repair or replacement of the damaged or
defective equipment. Keep the shipping materials for the carrier's inspection.
3 If you are returning the instrument under warranty or for service, repackaging
the instrument requires original shipping containers and materials or their
equivalents. Keysight Technologies can provide packaging materials identical
to the original materials. Refer to Service and Support information in the front
matter of this manual for the Keysight Technologies nearest you. Attach a tag
indicating the type of service required, return address, model number, and
serial number. Mark the container FRAGILE to insure careful handling. In any
correspondence, refer to the instrument by model number and serial number.
Returning attenuators under warranty
“Bad contacts” attenuators are returnable under warranty while “burned out”
attenuators are not. These terms are defined as follows:
– “Bad contacts”: Attenuation is within specifications at 8 GHz or higher;
attenuation is at least 3 to 5 dB higher than specification at DC and 1 kHz.
– “Burned out”: Attenuation is at least 3 to 5 dB higher than specification at DC
and entire rated frequency range.
Keysight 849x and 1158x Operating and Service Manual 21
1 Operating Instruction
NOTE
Operating Instruction
Operator’s check
The operator's check is supplied to allow the operator to make a quick check of
the attenuators prior to use or if a failure is suspected.
Using oscillator and SWR meter
Description
The attenuator is driven from a 50-ohm signal source at 1 kHz. The output level
from the attenuator is detected by a narrow-bandwidth voltmeter (that is, the
SWR meter). A reference level is set up on the detector using a through
connection in place of the attenuator. The attenuator is then inserted and the
change in the detector level is noted. This checks the low frequency accuracy of
the attenuator.
The SWR meter used in this check is calibrated for a square-law detector and
therefore the range changes and errors (read in dB) are twice that indicated by
the meter.
Quick-check procedure
1 Connect the equipment as shown in the Figure 1 except remove the attenuator
and connect the adapters directly together.
Figure 1 Equipment setup using oscillator and SWR meter
2 Set the test oscillator to 0.3 Vrms at 1 kHz.
22 Keysight 849x and 1158x Operating and Service Manual
Operating Instruction 1
3 Set the SWR meter range to 2 dB (expanded) or for the 3 dB, 6 dB, and 10 dB
(expanded) as appropriate and adjust its bandwidth to the center of the
adjustment range. Fine tune the oscillator frequency to obtain maximum meter
indication. Adjust the oscillator output to obtain the SWR meter reading in the
table below.
4 Connect the attenuator into the system, adjust the SWR meter range switch as
listed in Table 1 1, and verify that the SWR meter indicates within the limits as
shown Table 1 1.
Table 11 SWR verification
Attenuation (dB)
0 (system cal)
3 10 1.35 1.65
6 12 0.85 1.15
10 14 0.75 1.25
20 12 0.25 0.75
30 16 1.00 2.00
40 22 –0.25 1.25
50 26 0.75 2.25
60 32 –0.50 1.50
[a] Set SWR meter range to 10 dB and power level to 0.0 dB for 3 dB, 6 dB, and 10 dB attenuators only.
SWR meter range
(dB)
[a]
2 (or 10)
Minimum Actual Maximum
Meter indication (dB)
Set to 0.5 (or 0.0)
[a]
Keysight 849x and 1158x Operating and Service Manual 23
1 Operating Instruction
Using network analyzer
Description
All four s-parameters of the attenuator are measured using a network analyzer
that is already calibrated with the necessary settings.
Quick-check procedure
Use correct cables and adapters on the test ports of the network analyzer. This
depends on the type of the attenuator being checked. The equipment setup is as
illustrated in Figure 2.
1 Calibrate the network analyzer with appropriate settings and setup necessary.
2 Measure the S21 or/and S12 of the attenuator. Compare with the specification
to verify its electrical performance.
3 Measure the S11 and S22 of the attenuator. Compare with the specification to
verify its electrical performance.
Figure 2 Equipment setup using network analyzer
24 Keysight 849x and 1158x Operating and Service Manual
Making Connections
The attenuators should not bear any force or weight contributed by other devices
connected to them. The attenuators are bidirectional, that is, the signal may be
inserted from either end.
8490D/G
The 8490D 2.4-mm connectors mate with other 2.4-mm connectors of the
opposite sex.
The 8490G 1.85-mm connectors mate with other 1.85-mm connectors of the
opposite sex.
Making Connections 1
Figure 3 2.4-mm/1.85mm connector diagram
Keysight 849x and 1158x Operating and Service Manual 25
1 Making Connections
NOTE
8491A/B
The 8491A/B type-N connectors mate with all type-N connectors whose
dimensions conform to IEE STD 287.
Do not mate with 0.071 inch diameter pin male connector. Damage will result.
Figure 4 Type-N connector diagram
26 Keysight 849x and 1158x Operating and Service Manual
8493A/B
The 8493A/B has a male SMA jack on one end and a female SMA on the other.
These connectors mate with the opposite sex SMA connectors
Making Connections 1
Figure 5 SMA connector diagram
Keysight 849x and 1158x Operating and Service Manual 27
1 Making Connections
NOTE
8493C
The 8493C has a male 3.5-mm connector on one end and a female 3.5-mm
connector on the other side. These connectors mate with the opposite sex
3.5-mm or SMA connectors.
Continued mating with SMA connectors could degrade the 3.5-mm connector.
Figure 6 3.5-mm connector diagram
28 Keysight 849x and 1158x Operating and Service Manual
Performance Test
The attenuators can be tested to the accuracy of the specifications with a network
analyzer or equivalent equipment of suitable accuracy. If a network analyzer is
available, test the instrument using the procedure in the analyzer’s operating
manual.
Performance Test 1
Keysight 849x and 1158x Operating and Service Manual 29
1 Service Instructions
Service Instructions
Repair
The 8490D/G, 8491A/B the 8493A/B/C attenuators are not recommended for
repair since the cards must be mounted in cartridges to test and testing costs
more than a replacement attenuator.
Maintenance
The connectors, particularly the connector faces, must be kept clean. This is
especially true of the 8493A/B/C.
For instruction on connecting and care of your connectors, refer to the Microwave
Connector Care Quick Reference Card (08510-90360).
30 Keysight 849x and 1158x Operating and Service Manual
This information is subject to change
without notice. Always refer to the
English version at the Keysight
website for the latest revision.
© Keysight Technologies 2014 2019
Edition 6, June 26, 2019
Printed in Malaysia
*08491-90077*
08491-90077
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