Catherine C. Lewis and Robert J. Dolesh

Glenn Research Center, Cleveland, Ohio

Michael J. Garrett

Vantage Partners, LLC, Brook Park, Ohio

Space Power Facility Reverberation

Chamber Calibration Report

NASA/TM—2014-218363

November 2014
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Catherine C. Lewis and Robert J. Dolesh

Glenn Research Center, Cleveland, Ohio

Michael J. Garrett

Vantage Partners, LLC, Brook Park, Ohio

Space Power Facility Reverberation

Chamber Calibration Report

NASA/TM—2014-218363

November 2014

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Contents 

1.0 Introduction ......................................................................................................................................... 1

Background ............................................................................................................................... 1

Purpose ...................................................................................................................................... 1

Summary ................................................................................................................................... 1

Prerequisite Testing ................................................................................................................... 1

2.0 Applicable Documents ........................................................................................................................ 2

General ...................................................................................................................................... 2

Applicable Government Documents ......................................................................................... 2

Nongovernment Publications .................................................................................................... 3

Order of Precedence .................................................................................................................. 3

3.0 Test Setup ............................................................................................................................................ 3

Tolerances ................................................................................................................................. 3

SET Reverberation Chamber Setup........................................................................................... 3

3.2.1 Unloaded Chamber Calibration Probe Locations .......................................................... 6

3.2.2 Loaded Chamber Calibration Probe Locations .............................................................. 6

RF Equipment Setup ................................................................................................................. 6

4.0 Calibration Procedure .......................................................................................................................... 9

Time Estimate............................................................................................................................ 9

Roles and Responsibilities ......................................................................................................... 9

Safety ......................................................................................................................................... 9

Unloaded Calibration .............................................................................................................. 10

Loaded Calibration .................................................................................................................. 10

4.5.1 Estimate of Vehicle Loading ....................................................................................... 10

5.0 Results ............................................................................................................................................... 13

Test Summary.......................................................................................................................... 13

Chamber Uniformity, Unloaded .............................................................................................. 16

Chamber Uniformity, Loaded ................................................................................................. 16

Antenna Calibration Factor (ACF) .......................................................................................... 18

Chamber Loading .................................................................................................................... 19

Chamber Insertion Loss ........................................................................................................... 19

5.6.1 Chamber Quality Factor ............................................................................................... 21

Calculations of E-Fields Possible with 2011 Equipment ........................................................ 23

Calculated Power Required for 200 V/m E-Field ................................................................... 23

6.0 EMC-32 Data Verification and Validation ....................................................................................... 24

7.0 Conclusion ........................................................................................................................................ 26

Appendix A.—Acronyms ........................................................................................................................... 27

Appendix B.—Illustrations of E-field Probe Placement and RF Equipment Setups .................................. 29

Appendix C.—Relevant Equations For Chamber Loading Estimate .......................................................... 39

C.1 Chamber Parameters ................................................................................................................ 39

Appendix D.—Vehicle Approximated Physical Characteristics ................................................................ 41

D.1 Geometry ................................................................................................................................. 41

D.2 Theoretical Electromagnetic Properties of Vehicle ................................................................. 41

Appendix E.—Graphs of Calculated CEV Loading ................................................................................... 43

Appendix F.—Document History Log ........................................................................................................ 47

Appendix G.—Space Power Facility Reverberation Chamber Calibration Report Signature Page .......... 49

Appendix H.—Errata .................................................................................................................................. 51

NASA/TM—2014-218363 iii 
List of Tables 

Table 1.—Applicable Government Documents ............................................................................................ 2

Table 2.—Non-Government Applicable Documents .................................................................................... 3

Table 3.—Equipment Used for PBS Chamber Calibration .......................................................................... 7

Table 4.—Time estimate for Chamber Calibration....................................................................................... 9

Table 5.—Loading Material Physical Properties ........................................................................................ 12

Table 6.—Test Summary ............................................................................................................................ 14

Table 7.—X-Axis Standard Deviation Verification Calculations ............................................................... 25

Table 8.—Comparison of Calculated Values (Right) with EMC-32 Values (Left) .................................... 26

List of Figures 

Figure 1.—SET EMI Test Facility Chamber ................................................................................................ 2

Figure 2.—Polar Crane Orientation Relative to East Door ........................................................................... 4

Figure 3.—Mode Stirring Tuner, Inside the Chamber .................................................................................. 5

Figure 4.—EMC32 Hardware Setup Screenshot .......................................................................................... 7

Figure 5.—SMART80 Loading Test of Graphite and Coal ........................................................................ 11

Figure 6.—RF Absorbing Materials in Staging Area Outside the Chamber .............................................. 12

Figure 7.—Chamber Interior, Partial, Showing Graphite Ball Crates and Water Bottles .......................... 13

Figure 8.—Measurement Probe Mounted to Mast Support ........................................................................ 15

Figure 9.—Filling Process and Deployment of Measurement Probe Mounted to Helium Balloon ........... 16

Figure 10.—Chamber Uniformity in the Unloaded Configuration ............................................................. 17

Figure 11.—Chamber Uniformity in the Loaded Configuration ................................................................ 17

Figure 12.—Antenna Calibration Factor (ACF), Linear ............................................................................. 18

Figure 13.—Antenna Calibration Factor (ACF), in decibels ...................................................................... 18

Figure 14.—Chamber Loading Achieved During Chamber Calibration .................................................... 19

Figure 15.—Linear Insertion Loss for Empty and Loaded Chamber ......................................................... 20

Figure 16.—Chamber Insertion Loss Expressed in decibels ...................................................................... 20

Figure 17.—NIST Measured Insertion Loss ............................................................................................... 21

Figure 18.—Chamber Q Values Calculated from Test Data ...................................................................... 22

Figure 19.—Chamber Q: Unloaded, Loaded, and NIST (2009) ................................................................. 22

Figure 20.—Calculated E-Fields Possible with 2011 Equipment ............................................................... 23

Figure 21.—Calculated Transmit Power Required to Generate 200 V/m E-Field ..................................... 24

Figure B.1.—Generic Placement for 18 Probe Measurements Defining the Working Volume ................. 29

Figure B.2.—Probe Placement Configuration P1 ....................................................................................... 29

Figure B.3.—Probe Placement Configuration P2 ....................................................................................... 30

Figure B.4.—Probe Placement Configuration P3 ....................................................................................... 31

Figure B.5.—Probe Placement Configuration P4 ....................................................................................... 32

Figure B.6.—Probe Placement Configuration P5 ....................................................................................... 32

Figure B.7.—Probe Placement Configuration P6 ....................................................................................... 33

Figure B.8.—Loaded Chamber Probe Placement P6 .................................................................................. 34

Figure B.9.—RF Equipment Setup, 100 to 300 MHz ................................................................................. 34

Figure B.10.—RF Equipment Setup, 300 MHz to 1 GHz .......................................................................... 35

Figure B.11.—RF Equipment Setup, Unloaded Chamber, 1 to 4 GHz ...................................................... 35

Figure B.12.—RF Equipment Setup, Loaded Chamber, 1 to 4 GHz .......................................................... 36

Figure B.13.—RF Equipment Setup, 4 to 8 GHz ....................................................................................... 36

Figure B.14.—RF Equipment Setup, 8 to 18 GHz ..................................................................................... 37

Figure B.15.—RF Equipment Setup, 18 to 26 GHz ................................................................................... 37

Figure B.16.—RF Equipment Setup, 26.5 to 40 GHz ................................................................................ 38

NASA/TM—2014-218363 iv 
Figure D.1.—Geometries Used for the CEV Model ................................................................................... 42

Figure E.1.—Loss Tangent of Carbon Based Resin Composite versus Frequency .................................... 43

Figure E.2.—Theoretical Q of the CEV ..................................................................................................... 43

Figure E.3.—Theoretical Q of the Chamber Loaded With CEV ................................................................ 44

Figure E.4.—Theoretical Q of Empty Chamber, Vehicle, Loaded Chamber, and Threshold .................... 44

Figure E.5.—Comparison of Theoretical and Measured Q Values ............................................................ 45

NASA/TM—2014-218363 v 

Space Power Facility Reverberation Chamber Calibration Report 

Catherine C. Lewis and Robert J. Dolesh 

National Aeronautics and Space Administration 

Glenn Research Center 

Cleveland, Ohio 44135 

Michael J. Garrett 

Vantage Partners, LLC 

Brook Park, Ohio 44142 

1.0 Introduction 

Background 

The Space Power Facility (SPF) vacuum chamber at the NASA Glenn Research Center (GRC) Plum 

Brook Station (PBS) near Sandusky, Ohio, is being prepared for use as an electromagnetic compatibility 

(EMC) test facility. Tests and analyses of the SET Chamber have shown that the facility can be 

configured for reverberant chamber operation with a conductive paddle structure, called a tuner, for 

radiated susceptibility testing of equipment-under-test (EUT’s). 

Purpose

This document describes the process and results of calibrating the Space Environmental Test (SET) 

Electromagnetic Interference (EMI) Test facility (Figure 1) at PBS SPF according to the specifications of 

IEC61000-4-21 for susceptibility testing as required by the Electromagnetic Environmental Effects (E3) 

“Reverberant Chamber System Requirements Document,” GRC-SET-REQ-033 from 100 MHz to 40 

GHz. The procedures outlined in GRC-SET-PLAN-041, “Space Environmental Test (SET) Reverberation 

Chamber Calibration Test Plan,” were followed. 

Summary 

The chamber passed the field uniformity test, in both the empty and loaded conditions. However, it is 

anticipated that a crew vehicle of a similar size to the Orion Crew Exploration Vehicle (CEV) will require 

recalibration with more loading than was achieved with this test. In addition, the biggest challenge may be 

providing the power to generate a 200 V/m electric-field (E-Field). 

Prerequisite Testing 

The calibration testing was preceded by a shielding effectiveness test, a radio frequency (RF) 

emissions test, and a tuner performance test. 

The shielding effective test was performed before this calibration test to ensure the SPF chamber and 

chamber treatments provide the levels of shielding required by GRC-SET-REQ-033. The test was 

performed according to GRC-SET-PLN-042, “Electromagnetic Shielding Effectiveness of the Space 

Power Facility Test Plan.” 

After the shielding effectiveness test, an emissions test was performed to ensure that the levels 

radiated from the chamber are in compliance with limits specified by the National Telecommunications 

and Information Administration. This test was performed according to GRC-SET-PLN-043, “Radio 

Frequency Emissions of the Space Power Facility Test Plan.” 

NASA/TM—2014-218363 1 
Figure 1.—SET EMI Test Facility Chamber 

Following the shielding effectiveness test, a tuner performance test was conducted. The tuner 

performance test confirmed the design and placement of the tuner and transmitting antennas in the SPF 

chamber were suitable for reverberant testing. This test was performed according to GRC-SET-PLN-044, 

“Tuner Performance Test Plan.” 

2.0 Applicable Documents 

General 

This section lists documents cited in other sections of this plan. 

Applicable Government Documents 

The specifications, standards, and handbooks in Table 1 form a part of this document to the extent 

specified herein. 

TABLE 1.—APPLICABLE GOVERNMENT DOCUMENTS

Document Title Document Number Revision 

EMI Chamber Penetration Shields Installation and Removal PBSPF-091 Baseline 

Reverberant Chamber System Requirements Document GRC-SET-REQ-033 

Space Environmental Test (SET) Reverberation Chamber Calibration Test Plan GRC-SET-PLN-041 Baseline 

Electromagnetic Shielding Effectiveness of the Space Power Facility Test Plan GRC-SET-PLN-042 Baseline 

Radio Frequency Emissions of the Space Power Facility Test Plan GRC-SET-PLN-043 Baseline 

Tuner Performance Test Plan GRC-SET-PLN-044 

E3 hazard analysis report GRC-SET-RPT-045 Baseline 

Glenn Safety Manual GLM-QS-1800.1 

Glenn Occupational Health Programs Manual GLM-QS-1700.1 

NASA/TM—2014-218363 2 
Nongovernment Publications 

The publications in Table 2 form a part of this document to the extent specified herein. 

TABLE 2.—NON-GOVERNMENT APPLICABLE DOCUMENTS 

Document Title Document Number Revision 

Electromagnetic compatibility (EMC) –Part 4-21: Testing and measurement 

techniques –Reverberation chamber test methods 

IEC 61000-4-21 2003-08

Time-Domain Propagation Measurements of the NASA Space-Power Facility NTIA Technical Report 

TR-10-471 

Oct-2010 

An Electromagnetic Evaluation of the NASA Space Power Facility at Plum 

Brook Station 

NIST Tech Note TN1558 July 2011 

Environment Conditions and Test Procedures for Airborne Equipment RTCA/DO-160 Revision F 

December 

2007 

Order of Precedence 

In the event of a conflict between the text of this document and the references cited herein, the text of 

this document takes precedence. Nothing in this document, however, supersedes applicable laws and 

regulations unless a specific exemption has been obtained. 

3.0 Test Setup 

Tolerances 

A single E-Field probe is used for data gathering, to reduce/eliminate the errors introduced by 

different probe calibration factors. The spatial tolerance for positioning the E-Field probe throughout this 

procedure was 30 cm (1 ft). All E-Field probe positions were recorded to establish the actual boundaries 

of the working volume. The tuner and transmitting antenna positions were fixed with mounting hardware 

or permanently marked in the SPF chamber for repeatability throughout the calibration and subsequent 

EUT tests. The transmitting antenna orientations were also fixed with mounting hardware or permanently 

marked on their mounting fixtures. The tuner is removed for vacuum operations and re-installation will be 

within 1 in. of original location. 

SET Reverberation Chamber Setup 

Prior to doing any EMI testing PBSPF-091 EMI Chamber Penetration Shields Installation and 

Removal check-sheet needs to be performed. This check-sheet is very thorough and covers installation of 

the EMI Door 5 assembly, polar crane preparations, fabric covers installation, hatch flange, etc. 

It is uncertain the effect the orientation of the polar crane platform has on the E-Fields. For our testing the 

crane was clocked as shown in Figure 2. 

A single tuner was placed in the chamber, but outside of the working volume as shown in Figure B.2 

to Figure B.7. The working volume defined by this report is the vertical height between 1 m above the 

floor and 23 m (76 ft) above the chamber floor, and a horizontal area roughly 15 m (49 ft.) by 22 m 

(72 ft). The Z-fold tuner was mounted on a support structure designed for the SET chamber. 

NASA/TM—2014-218363 3 
Figure 2.—Polar Crane Orientation Relative to East Door 

The position and orientation of each transmitting antenna was meant to maximize stirring early in the 

E-Field propagation path and avoid direct illumination of the working volume. The position and direction 

of the transmitting antennas was based on the beam width of the antenna and the requirement to avoid 

direct illumination of the working volume. Transmitting antennas for frequencies above 300 MHz were 

mounted on a custom fixture near the Personnel Access door (sometimes referred to as “Door 5”) and 

interface panel to minimize cable losses, but also oriented to prevent direct illumination of the working 

volume. The biconical antenna, used for frequencies between 100 MHz (50 MHz) and 300 MHz, was 

mounted on a tripod 1 to 2 m above the chamber floor near the tuner, but not closer than 1 m to the tuner. 

Due to the dipole radiation pattern, the biconical transmitting antenna axis was oriented horizontally with 

one end pointing toward the center of the chamber. The position and polarity of each transmitting antenna 

and tuner was marked and recorded to duplicate the tuner and transmitting antenna positions per 

IEC61000-4-21. The mode stirring tuner is shown in Figure 3. 

The receiving antennas measured the power in the chamber at various arbitrary positions in the 

chamber after each tuner cycle. However, the orientation of the receiving antennas did not align with the 

transmitting antennas (they were cross-polarized to each other). Furthermore, for frequencies between 

300 MHz and 40 GHz, the receiving antenna was pointed away from the transmitting antenna to avoid 

direct illumination. For 100 to 300 MHz, the axis of the receiving biconical antenna was parallel to the 

axis of the receiving antenna to avoid direct illumination due to the omnidirectional radiation patterns of 

these antennas. The receiving antenna was mounted on a tripod 1 to 2 m above the chamber floor. 

NASA/TM—2014-218363 4 
Figure 3.—Mode Stirring Tuner, Inside the Chamber 

As mentioned earlier, the E-Field was measured with a single triaxial E-Field probe. The data taken in 

the x, y, and z axes are shown in Section 5.0. The probe was relocated to measure the E-Field in several 

pre-determined locations, and was moved to a new location after each tuner cycle. Probe positions near 

the tuner determined the sufficiency of stirring near the tuner and extended the working volume. The 

locations of the remaining probe positions were selected to define as large a rectangular floor volume as 

possible, as shown in Figure B.1. 

NASA/TM—2014-218363 5 
The three elevations of the probe were achieved using three different methods. The 1 m elevation was 

achieved by mounting the probe on a 2-in.-diam., 1 m custom Delrin (DuPont) tube mounted to an 

aluminum baseplate. To elevate the probe to 11 m the custom 1 m Delrin tube was attached to multiple 

2-in.-diam. carbon fiber segments and raised using a Will-Burt commercial mast system. For the 18 m 

elevations an 8-ft-diam. helium filled weather balloon was used. The E-Field probe was suspended 4 ft 

below this using a Delrin cross and parachute cord. A laser system was used to accurately position the 

probe, and four guy lines helped stabilize the movement of the balloon. The stillness of the air within the 

chamber kept the movement of the balloon to a minimum, and met the tolerance requirements of this test. 

3.2.1 Unloaded Chamber Calibration Probe Locations 

For the unloaded chamber calibration there were multiple variations of the number of probe locations 

(based on frequency ranges). For the 100 to 300 MHz band E-Field data was taken for 18 different probe 

positions but taken in two different sets. Seven of the 18 probe positions (see Figure B.3) were taken at 20 

paddle rotations to save time. The other 11 probe positions (Figure B.2) were sampled at 50 paddle 

rotations. Since the data set from the 11 probe positions met the IEC61000-4-21 field uniformity 

requirements the other 7 probe position’s data was not used. For the frequency band of 300 MHz to 

1 GHz, 18 E-Field probe locations were measured. Above 1 GHz where uniformity improves with 

decreasing wavelength all the frequency bands used the same ten probe locations (Figure B.8, minus 

center location). 

3.2.2 Loaded Chamber Calibration Probe Locations 

For the loaded calibration, one standard set of 11 probe positions for all the frequencies were used 

(Figure B.8). 

The elevation of the probe was achieved with a tripod at 1 m. To elevate the probe to 11 and 18 m, a 

helium filled balloon was used. The stillness of the air within the chamber kept the movement of the 

balloon to a minimum, and met the tolerance requirements of this test as verified by a laser positioning 

system. 

Between 100 MHz and 1 GHz, 18 E-Field probe locations were measured due to the unique shape of 

the SPF chamber. Because the IEC61000-4-21 field uniformity requirements were met below 1 GHz, only 

10 E-Field probe locations were required above 1 GHz where uniformity improves with decreasing 

wavelength. The 10 probe locations that were used from 1 to 40 GHz are shown in Figure B.8, minus the 

center location. 

The E-Field probe was mounted on a bracket which elevated it 35.5q above the horizontal plane 

which pointed the x-axis vertically upward. At each position on the circumference of the working volume, 

the probe axis was pointed toward the wall. For the center position, the probe axis was oriented toward 

the tuner. 

RF Equipment Setup 

The Main Computer controlled the RF equipment and tuner with the Rhode & Schwarz EMC32 

application (Figure 4). The version of EMC32 used to capture and process some of the data was 8.5 and 

version 8.53 was used to further process the data. The test was divided into frequency bands based on the 

bandwidth of the RF equipment. The frequency list, tuner steps, and RF setup for each frequency band are 

provided in Section 5.1. The RF equipment is listed in Table 3 and the configurations are provided in 

Figure B.9 to Figure B.16. 

NASA/TM—2014-218363 6 
Figure 4.—EMC32 Hardware Setup Screenshot 

TABLE 3.—EQUIPMENT USED FOR PBS CHAMBER CALIBRATION

50 to 300 

MHz 

300 to 1000 

MHz 

1 to 4 

GHz 

4 to 6 

GHz 

6 to 18 

GHz 

18 to 26 

GHz 

26 to 40 

GHz Qty. Item Mfr. Model 

number 

Calibration 

due date 

X X X X X X X 1 Signal Generator HP/Agilent E8257D 12/16/12 

X X X X X X X 1 Spectrum Analyzer Rohde & 

Schwarz FSV40 9/14/11 

X X X X X X X 1 Power Meter Agilent N1914A 3/8/12 

X X X X X X X 2 Power Sensors Agilent N8487A 10/1/11 

X X X X 2 PM 2.4-N Adapters Pasternack PE9503 

 X 2 PM 2.4-SMA 

Adapters Pasternack PE9654 

 X X 2 PM 2.4-2.9 Adapters Fairview 

Microwave SM3185 

X X X X X 1 DC Block Pasternack PE8123 

 X X 1 DC Block Fairview 

Microwave SD3779 

X X X X X 1 20 dB Attenuator Pasternack PE7017-20 

 X X 1 20 dB Attenuator Pasternack PE7046-20 

X X X X X 1 SG Adapter Fairview 

Microwave SM3085 

X X X X X 2 N-FDTHRU Adapter Pasternack PE9128 

 X X 1 SG Adapter Pasternack PE9456 

X X 1 Power Amplifier 1 AR Products 50WD1000M

2 

 X 1 Power Amplifier 2 AR Products 30S1G4M3 

 X 1 Power Amplifier 3 AR Products 15S4G8AM2 

 X 1 Power Amplifier 4 AR Products 10S6G18AM4 

 X 1 Power Amplifier 5 IFI T2618-40 

 X 1 Power Amplifier 6 CPI VZA6902J1 

 X X 1 50 /RDG Fairview 

Microwave ST4015 

NASA/TM—2014-218363 7 
TABLE 3.—EQUIPMENT USED FOR PBS CHAMBER CALIBRATION

50 to 300 

MHz 

300 to 1000 

MHz 

1 to 4 

GHz 

4 to 6 

GHz 

6 to 18 

GHz 

18 to 26 

GHz 

26 to 40 

GHz Qty. Item Mfr. Model number 

Calibration 

due date 

 X X 1 50 /RDG Fairview 

Microwave ST350PL 

 X X 1 RF Switch TBD TBD 

 X 1 Coax/Wvgd Adapter Fairview 

Microwave 42AC216 

 X 2 Coax/Wvgd Adapter Fairview 

Microwave 28AC206 

 X 1 Directional Coupler 3 AR Products DC7144A 

 X 1 Directional Coupler 4 AR Products DC7350A 

 X 1 Directional Coupler 5 AR Products DC7435A 

 X 1 Directional Coupler 6 AR Products DC7530 

 X 1 Directional Coupler 7 AR Products DC7620 

X 2 Bicon. Ant’s A & H System SAS 543FL 

 X 2 Log Periodic A & H System SAS 510-2 

 X X X 2 Horn Ant’s A & H System SAS-571 

 X X 2 Horn Ant’s A & H System SAS-574 

X X X X X 1 Cables Gore 0SQ01Q0107

8.7-T/V 

X X X X X 2 Cables Gore 0SQ01Q0111

18.0-T/V 

X X X X X 1 Cable L-Com CA6NMNM025 

X X X X X 1 Cable AH Systems SAC-18G-3 

 X X 1 Cables Gore 0K0CQ0CQ0

39.4-T/V 

 X X 2 Cables Gore 0K0CQ0CQ1

18.0-T/V

 X X 1 18 to 40 GHz 

RX Antenna Cables AH Systems SAC-40G-6 

X X X X X X X 2 Antenna Tripods AH Systems ATU-510 

X X X X X X X 1 Electric-field Monitor Amplifier 

Research FM7004 

X X X X X X X 1 Laser Interface Amplifier 

Research FI7000 

X X X X X X X 2 100 Ft Fiber Optic 

Cable Pair 

Amplifier 

Research FC 7010 

X X X X X X X 1 Electric-field Probe Amplifier 

Research FL7040 

X X X X X X X 1 Tuner Motor 

Controller Carousel AT11 

X X X X X X X 1 Tuner Turntable Carousel TBD 

X X X X X X X 1 Main Computer with 

EMC32 GRC Version 8.50 

X X X X X X X 1 Tuner Stand GRC TBD 

X X X X X X X 1 Tuner GRC TBD 

X X X X X X X 1 Ethernet Switch GRC TBD 

X X X X X X X 1 Video Computer GRC TBD 

X X X X X X X 1 ETS Lindgren 

Video Camera ETS Lindgren VC-04 

 Safety Circuit 

Assembly GRC TBD 

NASA/TM—2014-218363 8 
4.0 Calibration Procedure 

The reverberation test technique relies on the production of a statistically uniform field within one 

rotation of the stirring paddle(s). The physical features of the SPF vacuum chamber presented some 

unique challenges and many unknowns. To determine the viability of performing reverberation testing in 

the SET vacuum chamber, NASA collaborated with the National Institute of Standards and Technology 

(NIST) to test the chamber in an empty state and quantify its electromagnetic characteristics. While the 

NIST study did not intend to perform the chamber calibration, it established the chamber as a good 

reverberation environment. The end results of the NIST investigation can be read in “An Electromagnetic 

Evaluation of the NASA Space Power Facility at Plum Brook Station,” by Galen Koepke, John Ladbury, 

Dennis Camell, Jason Coder, Chriss Grosvenor, Randall Direen, and Jeff Guerriere. 

Time Estimate

The calibration of a reverberation chamber is a rigorous test. Based on recorded test time at the GRC 

Smart80 Facility, the calibration time per frequency band was estimated as shown in Table 4. This 

estimate assumes approximately 7 sec per frequency for power leveling and measurement stabilization, 20 

sec per tuner step, 15 min per probe position change, and 30 min for RF equipment setup. 

Each of the above tests must be repeated for the loaded calibration, which brings the total calibration 

time estimate to ~229 to 0 percent +20 percent hr. This estimate was used for planning purposes, and was 

very close to the actual time taken for the test. Refer to Section 5.1 for the Test Summary, which 

documents the test activities. 

Roles and Responsibilities 

The SET E3 calibration personnel were led by a Test Lead and a Test Operator. The Test Lead was 

the primary lead for safety related processes to ensure that the test was conducted in a safe manner in 

accordance with Section 4.3 of this document. 

The Test Operator was the primary lead for setting up the E3 equipment, running the test and 

collecting the required data. 

Safety

This test met the requirements of GLM-QS-1700.1, “Glenn Safety Manual,” and GLM-QS-1800.1, 

“Glenn Occupational Health Programs Manual,” which apply to all work done at Lewis Field and PBS. 

To manage the RF energy for personnel safety, a hard-wired safety circuit disabled the RF amplifiers and 

stopped the tuner motion: if an individual depressed the E-stop button in the chamber, if an individual 

depressed the E-stop button outside of the test chamber, if the Personnel Door was opened, or if the RF 

energy outside the chamber exceeded the limits specified in the E3 hazard analysis report, GRC-SETRPT-045. 

TABLE 4.—TIME ESTIMATE FOR CHAMBER CALIBRATION 

Frequency band 

(MHz) 

Tuner steps Probe positions Time to complete 

(hr) 

100 to 300 50 18 41.1 

300 to 1000 18 18 18.4 

1000 to 4000 12 18 14.6 

4000 to 8000 12 10 7

8000 to 18000 12 10 7

18000 to 26500 12 10 6.5 

26500 to 40000 12 10 6.5 

NASA/TM—2014-218363 9 
At the start of each test period, the Test Lead executed the Safety Checklist located in GRC-SETPLN-041, Appendix G, to ensure the chamber was safe for entry and the system was safe for testing. At 

the conclusion of each test period the Test Lead executed the safety checklist located in Appendix H to 

safely configure the chamber for shutdown. The safety circuit inhibits were tested every 30 days with the 

safety circuit inspection procedure located in GRC-SET-PLN-041, Appendix I. 

Unloaded Calibration 

The calibration was largely automated through the use of Rhode & Schwarz EMC32 software on a 

computer. Before testing began, calibration data for all equipment was collected and programmed into the 

EMC32 data files. The Test Operator set up the equipment according to the configurations in Figure B.9 

through Figure B.16 and the procedures in GRC-SET-PLN-041, Appendix D. The Test Lead then 

executed the safety checklist for chamber entry, and executed the calibration using EMC32 software as 

described in the following paragraphs. 

The Test Operator initiated EMC32 software which moved the tuner into position 1 and began 

sweeping the signal generator with a continuous wave from the start of the frequency band. The signal 

was amplified through the power amplifiers to a power level of 2 W. (To compensate for anticipated high 

chamber insertion loss, the level was raised to 4 W, from 18 to 26.5 GHz.) The level was maintained 

through the power meter measurements from the directional coupler at the output of the amplifier. Once 

the power was leveled, and after a stabilization time of approximately 1 sec, the E-Field was measured by 

the E-Field probe. The spectrum analyzer frequency was controlled to match the signal generator 

frequency during the scan. The software recorded the power level measured by the antenna and spectrum 

analyzer. 

After the signal measurements were recorded, the signal generator and spectrum analyzer were set to 

the next frequency and the process was repeated through the frequency band. After recording the E-Field 

and power level of the last frequency in the band, the tuner was moved to the next position and the 

frequency sweep repeated. Once the tuner stepped through each position and frequency sweep, the 

software notified the Test Operator to change the sensor position. The Test Operator moved the E-Field 

probe and receiving antenna to their next positions. The receiving antenna was moved to a random 

position in the working volume at least 1 m from the previous position and changed at least 20q in each 

axis from its previous orientation. After completion of all probe positions in a frequency band, the data 

was evaluated as described in Section 5.0, Results. 

Loaded Calibration 

From IEC-61000-4-21, section B.1.5: “In order to determine if the chamber is adversely affected by 

an EUT which “loads” the chamber, perform a one-time check of the chamber field uniformity under 

simulated loading conditions. It is suggested the “loaded” chamber calibration be carried out only once in 

the life of the chamber or after major modification to the chamber.” The chamber should be loaded to at 

least the level expected during normal testing. The IEC specification recommends a factor of 16 reduction 

in Q, or 12 dB delta in Antenna Calibration Factor (ACF) as a loading goal. The ACF represents a ratio of 

reverberant chamber power to transmitted input power. 

4.5.1 Estimate of Vehicle Loading 

In February 2010, a quick-look calculation was made to determine the potential loading that the Orion 

CEV would present to the SET vacuum chamber. Many assumptions and data interpolations were made, 

with the goal of obtaining a ballpark loading value. Appendix B shows illustrations of the E-Field 

placements and RF equipment setups, Appendix C lists the relevant equations, Appendix D contains the 

CEV approximated physical characteristics used, and Appendix E contains graphs obtained from the 

equations using the approximated vehicle characteristics. 

NASA/TM—2014-218363 10 
Once it was confirmed by completing Section 4.4 that the chamber E-Field uniformity conformed to 

the IEC61000-4-21 requirements for an unloaded chamber, the test was repeated with a simulated 

“maximum test article” load to verify that the chamber can be used with EUT while maintaining E-Field 

uniformity. 

Loading a chamber of this size was a challenge, as few publications can be found on loading 

techniques with respect to Insertion Loss versus material type and quantity. Using a study by NIST from 

2003,1

 it was determined that if we wanted an insertion loss of 12 dB, we needed a ratio of Qempty to Qloaded

of 15.8. In their study, NIST used water spheres taking up ~ 0.029 percent of the experiment chamber 

volume, and representing 0.344 percent of the chamber Surface Area (SA) to achieve this amount of Q 

reduction. In addition, tests performed in a standard sized reverberation chamber (a SMART80), showed 

promising results with 21⁄2 in. graphite balls and 50 lb bags of coal pieces, taking up 0.026 percent of the 

chamber volume and presenting 0.45 percent of the chamber SA. Figure 5 shows the loading results 

obtained in the Lewis Field SMART80 chamber. 

The graphite consumed 0.005 percent of the chamber volume. The coal consumed 0.025 percent of 

the chamber volume. The graphite inhibited direct reflection across 0.14 percent of the chamber surface. 

The coal inhibited direct reflection across an additional 0.31 percent of the chamber surface. 

An analysis was performed to determine materials and quantities for a reasonable amount of loading 

effect in the larger PBS vacuum chamber. A combination of terminated UHF and VHF antennas, crates 

filled with graphite balls, pallets of coal, and 5-gal bottles of water were used as loading materials, as 

listed in Table 5. The total cost for loading the chamber was under $2000. 

Figure 5.—SMART80 Loading Test of Graphite and Coal 

1

 Christopher L. Holloway, David A. Hill, John M. Ladbury, and Todd M. Lammers, National Institute of Standards 

and Technology (NIST), 325 Broadway, Boulder, CO. “Assessing Loaded Reverberation Chambers: Calculating 

Threshold Metrics”, Electromagnetic Compatibility, 2003 IEEE International Symposium on, 2003 

NASA/TM—2014-218363 11 
TABLE 5.—LOADING MATERIAL PHYSICAL PROPERTIES 

Material Volume, 

m3

Surface area, 

m2

Chamber 

volume, 

% 

Chamber 

surface area, 

% 

Target frequencies 

Four VHF antennas, terminated N/A N/A N/A N/A 30 to 300 MHz 

Two VHF/UHF antennas, terminated N/A N/A N/A N/A 30 MHz to 3 GHz 

400 bags of coal (did not use) 2.21 0.95 0.01 1.66 100 to 700 MHz 

Eleven crates, containing approximately 

50,000 2.5 in. diam. graphite balls 6.7 58.25 0.029 1.016 1 to 10 GHz 

500 gal of water 1.9 19.2 0.008 0.335 2.5 to 40 GHz 

Figure 6.—RF Absorbing Materials in Staging Area Outside the Chamber 

Due to the enormous size of the SPF vacuum chamber, and the cleanliness restrictions placed on the 

absorptive materials, the desired goal of 12 to 16 dB of loading was not achieved. In retrospect, the 

amount of materials placed in the chamber should have been greater. Looking at Figure E.4, the measured 

chamber loading (ז (should be below the theoretical chamber/vehicle line (྾) at all times. The actual 

loading obtained ranged between 3 dB at the lowest frequencies to 9 dB around 1 GHz, and back down to 

approximately 6 dB at the highest frequencies. Refer to Figure 14 for the graph of measured chamber 

loading versus frequency. 

In Figure 6, the crates of graphite balls are shown on the right, and the 5-gal bottles of water are 

shown on the left. 

The loading material was placed arbitrarily in the working volume, near the perimeter of the chamber, 

as shown in Figure 7. Placement of the loading material outside of the working volume is allowable per 

IEC 61000-4-21. In retrospect, better loading could have been achieved with the materials placed inside 

the working volume to expose them to more wave reflections. 

NASA/TM—2014-218363 12 
Figure 7.—Chamber Interior, Partial, Showing Graphite Ball Crates and Water Bottles 

Once the loading was placed in the chamber, the calibration process in Section 4.4 was repeated and 

the data processed according to IEC61000-4-21, section B.1.5, and Section 5.0 of this report. 

5.0 Results 

Test Summary 

After performing safety and equipment checkouts, the test was executed between June 30, 2011 and 

July 28, 2011. The test instruments were operated and data were collected by the software program EMC32, developed by Rhode & Schwarz. The files were saved internally to the EMC-32 program, named 

according to Table 4 of GRC-SET-PLN-041, with the following nomenclature: 

F1M1F2M2_XC_YYMMDDz, where 

F1M1 = F1 Start Frequency, M1 Multiplier (M for Mega, G for Giga) 

F2M2 = F2 Finish Frequency, M2 Multiplier (M for Mega, G for Giga) 

XC = UC for Unloaded Chamber, LC for Loaded Chamber 

YY = 11 

MMDD = 2-digit month, 2-digit day 

z = a, b, c, etc. for test re-run attempts if necessary 

Testing began with the chamber in an unloaded configuration. It was soon realized that mounting the 

probe on a mast to achieve the highest chamber measurements was not practical. Refer to Figure 8 for a 

picture of the mast in its extended position. The support structure was redesigned to utilize a helium-filled 

NASA/TM—2014-218363 13 
balloon to raise the probe to the desired height. It was found that the air inside the chamber was still 

enough to allow for very stable positioning with guy wires. In addition, a greater height was achievable 

with this design, 23 m (76 ft) instead of 18 m (58.5 ft). See Figure 9 to see the filling process and final 

configuration for the helium balloon probe support design. 

The original test plan, presented in GRC-SET-PLN-041, Appendix A, was also altered during the test. 

This was to account for the updated chamber configuration layouts, probe locations, and paddle positions, 

as shown in Table 6. 

TABLE 6.—TEST SUMMARY 

Unloaded Chamber 

Test 

dates 

a

Frequency Calibration 

layout 

diagram 

Probe 

positions 

Tuner 

positions 

Scan time 

per probe 

position 

(min) 

Total scan 

time 

(hr) 

Setup time 

(min per 

probe 

position) 

Total 

setup time 

(hr) 

Reconfiguration time 

(hr) 

7/11 - 7/12 100 to 300 (50) P1 11 50 85 15.58 15 2.75 1 

7/11 - 7/13 100 to 300 (20) P2 7 20 45 5.25 15 1.75 0 

6/30 - 7/15 300 to 1000 P3 18 18 40 12.00 15 4.5 1 

6/30 - 7/5 300 to 1000 P4 5 18 40 3.33 15 1.25 1 

7/6 - 7/13 1000 to 4000 P5 10 12 20 3.33 15 2.5 1 

7/6 - 7/13 4000 to 8000 P5 10 12 20 3.33 15 2.5 1 

7/7 - 7/14 8000 to 18000 P5 10 12 20 3.33 15 2.5 1 

7/7 - 7/14 18 to 26 P5 10 12 20 3.33 15 2.5 1 

7/8 - 7/14 26 to 40 P5 10 12 20 3.33 15 2.5 1 

------------ ------------ -- -- -- -- 52.8333333 -- 22.75 8 

Total 7 days(12 hr days) 

Loaded Chamber 

Test 

dates 

a

Frequency Calibration 

layout 

diagram 

Probe 

positions 

Tuner 

positions 

Scan time 

per probe 

position 

(min) 

Total scan 

time 

(hr) 

Setup time 

(min per 

probe 

position) 

Total 

setup time 

(hr) 

Reconfiguration time 

(hr) 

7/26 - 7/28 100 to 300 (50) P6 11 50 85 15.58 15 2.75 1 

N/A 100 to 300 (20) P6 7 20 45 5.25 15 1.75 0 

7/22 - 7/26 300 to 1000 P6 18 18 40 12.00 15 4.5 1 

7/21 1000 to 4000 P6 10 12 20 3.33 15 2.5 1 

7/20 - 7/21 4000 to 8000 P6 10 12 20 3.33 15 2.5 1 

7/20 8000to 18000 P6 10 12 20 3.33 15 2.5 1 

7/19 18 to 26 P6 10 12 20 3.33 15 2.5 1 

7/18 - 7/19 26 to 40 P6 10 12 20 3.33 15 2.5 1 

------------ ------------ -- -- -- -- 49.5 -- 21.5 7 

Total 6.5 days (12 hr days) 

a

Frequency is in MHz through 18,000, then switches to GHz for the last two rows (18 – 26 and 26 – 40) 

 

NASA/TM—2014-218363 14 
Figure 8.—Measurement Probe Mounted to Mast Support 

NASA/TM—2014-218363 15 
Figure 9.—Filling Process and Deployment of Measurement Probe Mounted to Helium Balloon 

Chamber Uniformity, Unloaded 

At the end of testing all of the frequency bands in the unloaded configuration, the program EMC-32 

created a summary file, taking the appropriate value from each of the many files and placing it in a 

summary table in order to calculate field uniformity. Verification of the program’s methodology can be 

found in Section 6.0, EMC-32 Data Verification and Validation. Referencing Figure 10, it can be seen 

that the chamber uniformity meets the criteria specified in IEC-61000-4-21, Table B.2, for all frequencies 

between 100 MHz and 40 GHz in the unloaded configuration. 

Chamber Uniformity, Loaded 

The chamber was loaded with a combination of RF absorbing materials to obtain as much loading as 

possible while complying with the chamber’s unique cleanliness (vacuum) requirements. Terminated 

antennas, graphite balls, and water were used to cover the test frequency spectrum. For more detailed 

information about the loading calculations and material arrangement, refer to Section 5.5, Chamber 

Loading. The Chamber uniformity with the loading materials installed is shown in Figure 11. 

The graph in Figure 11 shows 3 points in the Y direction, and 3 points in the Z direction that are 

above the limit. The specification states that “a maximum of three frequencies per octave may exceed the 

allowed standard deviation by an amount not to exceed 1 dB of the required tolerance”. The over-limit 

points contain only 2 within one octave, therefore the “frequencies per octave” uniformity requirement 

was met for all individual axes plus the XYZ composite. In addition, the maximum value is 0.234 dB over 

the limit, meeting the amplitude requirement. In summary, the field uniformity requirement in 61000-4-

21, section B.1.1 was met. 

NASA/TM—2014-218363 16 
Figure 10.—Chamber Uniformity in the Unloaded Configuration 

Figure 11.—Chamber Uniformity in the Loaded Configuration 

NASA/TM—2014-218363 17 
Antenna Calibration Factor (ACF) 

The receiving ACF is determined as an intermediary step to allow the calculation of chamber loading, 

and is shown in Figure 12 and Figure 13. It is defined as the ratio of the average received power to the 

average input power, averaged over the measurement locations and paddle positions. The ACF ratio is 

calculated with linear power (Watts), and is always less than one. Hence, when converted to decibels, the 

value is always negative. Many times the ACF in decibels is graphed as an absolute value, with the 

understanding that it is a “loss”, and the negative property is understood. 

Figure 12.—Antenna Calibration Factor (ACF), Linear 

Figure 13.—Antenna Calibration Factor (ACF), in decibels 

0

0.0001

0.0002

0.0003

0.0004

0.0005

0.0006

0.0007

0.0008

0.0009

0.001

0.0011

0.0012

0.0013

0.0014

0.0015

100 1000 10000

Antenna Calibration Factor

Frequency (MHz)

Antenna Calibration Factor = Pave_rec (Watts)/Pave_in (Watts)

ACF Unloaded

ACF Loaded

NASA/TM—2014-218363 18 
Figure 14.—Chamber Loading Achieved During Chamber Calibration 

Chamber Loading 

The chamber loading is calculated in decibels. The purpose of this calculation is to show that with the 

loading achieved at a given frequency, the chamber field uniformity requirement is met. We showed that 

the uniformity was met for the loading shown in Figure 11 in Section 5.3. When a test article wishes to 

use this facility, the EUT and its support equipment are placed in the chamber. Then the average received 

power at one probe location and the required tuner steps is used to calculate the loading provided by the 

EUT and support equipment. If the loading exceeds the values shown in Figure 14, then there is the 

possibility that the chamber may be loaded to the point where field uniformity is affected. In such a case, 

the chamber uniformity measurements outlined in IEC-61000-4-21, section B.1.1 must be repeated with 

the EUT in place or with a simulated load equivalent to the EUT. 

Chamber Insertion Loss 

The chamber insertion loss provides information necessary for other calculations. It is defined as the 

average, over the antenna locations, of the ratio of the maximum power received to the average input 

power. The power unit used for this calculation must be in Watts. Once calculated in a linear fashion, the 

insertion loss can be converted to decibels by taking its base 10 log and multiplying by 10. Figure 14 and 

Figure 15 show the linear insertion loss, and Figure 16 shows the log based insertion loss. The data 

obtained during this chamber calibration test differs from the data taken by NIST in 2009 by a factor of 

~100 (20 dB), as shown in Figure 17. 

NASA/TM—2014-218363 19 
Figure 15.—Linear Insertion Loss for Empty and Loaded Chamber 

Figure 16.—Chamber Insertion Loss Expressed in decibels 

-0.001

1.1E-17

0.001

0.002

0.003

0.004

0.005

0.006

0.007

0.008

100 1000 10000

Chamber Linear Insertion Loss = Average over Working Volume of 

PMaxRec (Watts) / PAveIn (Watts)

Unloaded Insertion Loss

Loaded Insertion Loss

-100

-90

-80

-70

-60

-50

-40

-30

-20

100 1000 10000

Insertion Loss (dB)

Frequency (MHz)

Chamber Insertion Loss in dB = 

10log10 (PMaxRec (Watts) / PAveIn (Watts)

Unloaded IL (dB)

Loaded IL (dB)

NASA/TM—2014-218363 20 
Figure 17.—NIST Measured Insertion Loss 

5.6.1 Chamber Quality Factor 

The calculation of chamber Q performed internal to EMC-32 originally differed from the calculations 

based on the below formulas for Q and QThreshold: 

Input 3

AveRec 2

P

16 V P Q OS > @

O

S 24 3 V Q

2 3 1 3

Threshold

where 

V = Chamber Volume = 23426 m3 

Throughout the course of 2011 and 2012, it was discovered that the data reduction resident in EMC32 contained errors. Once the errors were corrected and the raw data was run through the reduction 

algorithm, the measured/calculated Q values correlated quite nicely with those obtained by NIST in 2009. 

In addition to the difference between the hand calculations and the values provided by EMC-32 for 

the Q data, there was a block of data between 300 MHz and 1 GHz that seemed to have a Q calculation 

error within the EMC-32 output. It is believed that an attenuation factor was not input correctly at the 

time of the measurements, causing the numbers to be off. The graph of the Unloaded Chamber Q in 

Figure 18 contains a correction in this frequency band, based on the shape of the Q curve of the loaded 

chamber. This was also corrected by Rhode & Schwarz. Figure 19 compares the data obtained in this test 

compared to the data obtained by NIST. 

NASA/TM—2014-218363 21 
Figure 18.—Chamber Q Values Calculated from Test Data 

Figure 19.—Chamber Q: Unloaded, Loaded, and NIST (2009) 

NASA/TM—2014-218363 22 
Figure 20.—Calculated E-Fields Possible with 2011 Equipment

Calculations of E-Fields Possible with 2011 Equipment

With the equipment described in Section 3.3, the E-Fields possible with various loads was calculated, 

as shown in Figure 20. 

Calculated Power Required for 200 V/m E-Field 

To obtain the target 200 V/m field required by NASA EMC test specifications, the required amplifier 

output is shown in Figure 21, calculated using the following formula: 

2

W * Chamber Loading Factor

m

V Probe Cal Factor 

m

V Target Field

Amplifier Output (W) =

 ̧

 ̧

 ̧

 ̧

1

·

 ̈

 ̈

 ̈

 ̈

©

§

 ̧

1

·  ̈

©

§

 ̧

1

·  ̈

©

§

NASA/TM—2014-218363 23 
Figure 21.—Calculated Transmit Power Required to Generate 200 V/m E-Field 

6.0 EMC-32 Data Verification and Validation 

To ensure that the methodology of data manipulation within EMC-32 was understood, a subsection of 

data, taken at frequencies between 8 and 18 GHz, was verified. The process involved the following steps: 

1. Open and export 120 files as Microsoft Excel (Microsoft Corporation) spreadsheets,

corresponding to the 10 probe positions and 12 paddle positions measured at this frequency band.

2. For each of the 120 files, at each of the 6 frequencies, take the X, Y, and Z measured E-Field

(V/m) sensor level and place it into a spreadsheet cell. (120 measurement columns by 6

frequencies)

3. For each probe position, find the maximum E-Field and normalize it by the square root of the

input power. (10 probe position columns by 6 frequencies)

4. Find the MEAN of the maximums from Step 3. (1 column by 6 frequencies)

5. Subtract the Mean, obtained in Step 4, from the normalized maximum obtained in Step 3, and

square the resulting value. (10 probe positions by 6 frequencies)

6. Add the 10 values per frequency, obtained in 5, together. Divide by 9, and take the square root to

obtain the normalized standard deviation, relative to the normalized mean value. Multiply this

value by 1.06, according to the directions in IEC61000-4-21. (9 represents the number of probe

positions minus 1)

7. Add the standard deviation obtained in Step 6 to the normalized mean value obtained in Step 4,

divide by the mean value from Step 4, and convert to decibels by taking the log(10) of the

resulting value and multiplying by 20. (The multiplier is 20 because the measurement units are

volts per meter.)

NASA/TM—2014-218363 24 
Steps 3 to 7 were repeated to obtain X-axis, Y-axis, Z-axis, and XYZ composite field confirmation. 

The X, Y, and Z were verified within rounding error. The XYZ composite was close but not exact. It is 

suspected that the difference lies in the author’s understanding of the vector calculation. In Table 7, the 

calculations for the X-axis are shown. Table 8 shows the calculations for X, Y, and Z axes, and the 

composite XYZ, compared to the values provided by EMC-32 software. The like-colored columns should 

be compared. The frequencies between 26.5 GHz and 40 GHz were analyzed as above for further 

verification and validation, and the results are also shown in Table 8. 

The values used in Table 7, and those obtained for the Y and Z axes, were used for all subsequent 

calculations (EMC, Chamber Loading, Insertion Loss, and Chamber Q). By verifying the software’s 

calculation of field uniformity, the other calculations were quickly verified to be accurate as well. 

TABLE 7.—X-AXIS STANDARD DEVIATION VERIFICATION CALCULATIONS 

Frequency 

(MHz) 

Probe position 

1 2 3 4 5 6 7 8 9 10 

Maximum X-component of the e-field at each probe position, normalized to the square root of the input power 

8858.670000 6.500 4.905 7.136 5.764 6.442 5.660 6.674 9.472 9.389 11.251 

10000.000000 5.615 7.014 6.419 7.039 6.929 10.058 7.653 10.131 7.394 10.341 

11288.380000 6.425 4.843 6.907 6.966 6.301 3.295 6.437 6.168 7.917 6.774 

12742.750000 6.455 6.869 6.625 6.987 6.342 3.651 4.560 6.475 7.061 6.599 

14384.500000 7.108 7.043 5.802 6.603 6.447 11.324 7.557 8.630 6.074 7.332 

16237.770000 7.146 7.134 5.996 5.306 6.952 3.587 9.898 7.738 11.513 7.926 

Normalized mean value of the max values of the x-component of the e-field 

8858.670000 7.319 

10000.000000 7.859 

11288.380000 6.203 

12742.750000 6.162 

14384.500000 7.392 

16237.770000 7.320 

Squared (normalized max minus normalized mean) 

8858.670000 0.672 5.829 0.034 2.418 0.770 2.754 0.417 4.636 4.286 15.456 

10000.000000 5.036 0.714 2.075 0.673 0.866 4.835 0.043 5.159 0.216 6.158 

11288.380000 0.049 1.851 0.496 0.581 0.009 8.459 0.055 0.001 2.936 0.325 

12742.750000 0.085 0.499 0.214 0.680 0.032 6.306 2.567 0.098 0.807 0.191 

14384.500000 0.081 0.122 2.527 0.623 0.893 15.458 0.027 1.533 1.738 0.004 

16237.770000 0.030 0.034 1.751 4.055 0.135 13.931 6.647 0.175 17.583 0.367 

Normalized standard deviation of the x-component, relative to the normalized mean value 

8858.670000 2.034991477 2.157 

10000.000000 1.692315592 1.794 

11288.380000 1.280713479 1.358 

12742.750000 1.129399861 1.197 

14384.500000 1.598838541 1.695 

16237.770000 2.228812049 2.363 

Expressed in decibels, normalized standard deviation of the C-component, relative to the normalized mean value 

8858.670000 1.058 2.243 

10000.000000 0.973 1.786 

11288.380000 0.932 1.719 

12742.750000 0.922 1.542 

14384.500000 0.837 1.793 

16237.770000 1.128 2.430 

Not shown: E-Field Sensor Level Data, X-axis, for 12 Paddle positions and 10 Probe locations 

NASA/TM—2014-218363 25 
TABLE 8.—COMPARISON OF CALCULATED VALUES (RIGHT) WITH EMC-32 VALUES (LEFT) 

Frequency x std dev y std dev z std dev xyz std dev x STD DEV y STD DEV z STD DEV xyz STD DEV 

EMC 32 V&V 

8858.67 2.242 1.262 1.459 1.586 2.243 1.263 1.459 1.588 

10000.00 1.786 1.350 1.441 1.480 1.786 1.350 1.439 1.490 

11288.38 1.717 1.746 1.496 1.529 1.719 1.749 1.499 1.438 

12742.75 1.543 1.350 1.056 1.277 1.542 1.351 1.058 1.016 

14384.50 1.794 1.586 1.442 1.489 1.793 1.584 1.443 1.702 

16237.77 2.429 1.270 1.388 1.651 2.430 1.271 1.389 1.626

29763.51 2.344 1.250 1.250 1.696 2.342 1.3093 1.250 1.737 

33598.18 2.089 1.480 1.480 1.592 2.086 1.5409 1.480 1.173 

39000.00 2.263 2.174 2.174 1.909 2.268 1.5458 2.173 2.085

7.0 Conclusion 

The SPF E3 Chamber was calibrated, according to the specifications contained in IEC 61000-4-21. 

The data shows that the standard deviation of the field in each axis and composite XYZ meets the 

uniformity requirement. In addition, the loaded chamber meets the same uniformity requirement. The 

chamber is therefore certified for reverberation method testing, as long as the EUT loads the chamber less 

than the frequency dependent values shown in Figure 14. 

NASA/TM—2014-218363 26 
Appendix A.—Acronyms 

ACF Antenna Calibration Factor 

CEV Crew Exploration Vehicle 

CM Crew Module 

E3, E3

 Electromagnetic Environmental Effects 

EM electromagnetic 

EMC electromagnetic compatibility or control 

EMI electromagnetic interference 

EUT equipment under test 

FCC Federal Communications Commission

GRC NASA Glenn Research Center 

GSHMS Glenn Safety and Health Management System 

LAS Launch Abort System 

NASA National Aeronautics and Space Administration 

NIST National Institute of Standards and Technology 

NPR NASA Procedural Requirements 

NTIA National Telecommunications and Information Administration 

OME Outer Main Engine 

OML Outer Mold Line 

PBS Plum Brook Station 

RF radio frequency 

SE shielding effectiveness 

SET Space Environmental Test 

SM Service Module 

SPF Space Power Facility 

SRD System Requirements Document 

TBD to be determined 

V/m volts per meter, electric field strength 

PV/m microvolts per meter, electric field strength 

NASA/TM—2014-218363 27 

Appendix B.—Illustrations of E-field Probe 

Placement and RF Equipment Setups 

Figure B.1.—Generic Placement for 18 Probe Measurements Defining the Working Volume 

Figure B.2.—Probe Placement Configuration P1 

NASA/TM—2014-218363 29 
Figure B.3.—Probe Placement Configuration P2 

NASA/TM—2014-218363 30 
Figure B.4.—Probe Placement Configuration P3 

NASA/TM—2014-218363 31 
Figure B.5.—Probe Placement Configuration P4 

Figure B.6.—Probe Placement Configuration P5 

NASA/TM—2014-218363 32 
Figure B.7.—Probe Placement Configuration P6 

NASA/TM—2014-218363 33 
Figure B.8.—Loaded Chamber Probe Placement P6 

Signal Generator Direc. Coupler 

Power Meter

Agilent N1914A

& N8487A (2)

Tx Antenna

Spectrum Analyzer

Rohde & Schwarz Rx Antenna

Motor Controller 

Carousel AT11

E-Field Probe

Amplifier Research 

FL7040

SPF CHAMBER

Agilent E8257D

Fiber Optic TxRx Pair

RF Amplifier 

Amplifier Research

AR 50WD1000M2 

Gore 

0SQ01Q011180-T/V

8324498

Fairview Microwave

SM 3085 Adapter

AR DC 3010A

Fwd Rev

CH A CH B

AH Systems

SAC-18G-3

AH Systems

SAS-543FL

Pasternak

PE 9503 

Adapter (2)

Pasternak

PE9128

F.O Feedthru

Adapter

GRC Tuner

Carousel 

Turntable

DC Block

Pasternack

PE8123

Attenuator

Pasternack

PE7017-20

AH Systems

SAS-543FL

Pasternak

PE9128

Gore 0SQ01Q011180-T/V

8324499

LCom

CA-6NMNM025

Ethernet

Field Monitor

Amplifier Research

FM7004

Laser Interface

Amplifier Research

FL7000

Gore

0SQ01Q010787-T/V

8324497

F.O Feedthru

Adapters

Fiber Optic Tx Rx Pair

Fiber Optic Power

FSV40 w/ N adapter

Main Computer

EMC32 Software

GPIB/Ethernet 

Controller

GPIB

Fiber Optic Tx Rx Pair

Ethernet

Switch

Ethernet

Figure B.9.—RF Equipment Setup, 100 to 300 MHz 

NASA/TM—2014-218363 34 
Signal Generator Direc. Coupler 

Power Meter

Agilent N1914A

& N8487A (2)

Tx Antenna

Spectrum Analyzer

Rohde & Schwarz Rx Antenna

Motor Controller 

Carousel AT11

E-Field Probe

Amplifier Research 

FL7040

Agilent E8257D

RF Amplifier 

Amplifier Research

AR 50WD1000M2 

Fairview Microwave

SM3085 Adapter

AR DC 3010A

Fwd Rev

CH A CH B

AH Systems

SAC-18G-3

AH Systems

SAS-510-2

Pasternak

PE 9503

Adapter (2)

F.O Feedthru

Adapter

GRC Tuner

Carousel 

Turntable

DC Block

Pasternack

PE8123

Attenuator

Pasternack

PE7017-20

AH Systems

SAS-510-2

SPF CHAMBER

Fiber Optic TxRx Pair

Field Monitor

Amplifier Research

FM7004

Laser Interface

Amplifier Research

FL7000

Pasternak

PE9128

Pasternak

PE9128

F.O Feedthru

Adapters

Fiber Optic Tx Rx Pair

Fiber Optic Power

FSV40 w/ N adapter

Main Computer

EMC32 Software

GPIB/Ethernet 

Controller

GPIB

Gore 

0SQ01Q011180-T/V

8324498

Gore 0SQ01Q011180-T/V

8324499

LCom

CA-6NMNM025

Gore

0SQ01Q010787-T/V

8324497

Fiber Optic Tx Rx Pair

Ethernet Ethernet

Switch

Ethernet

Figure B.10.—RF Equipment Setup, 300 MHz to 1 GHz 

Signal Generator Direc. Coupler 

Power Meter

Agilent N1914A

& N8487A (2)

Tx Antenna

Spectrum Analyzer

Rohde & Schwarz

Rx Antenna

Motor Controller 

Carousel AT11

E-Field Probe

Amplifier Research 

FL7040

Agilent E8257D

RF Amplifier

Amplifier Research

30S1G4M3

Fairview Microwave 

SM3085 Adapter

AR DC 7144A

Fwd Rev

CH A CH B

AH Systems

SAS-571

Pasternak

PE 9503

Adapter (2)

F.O Feedthru

Adapter

GRC Tuner

Carousel 

Turntable

DC Block

Pasternack

PE8123

Attenuator

Pasternack

PE7017-20

AH Systems

SAS-571

SPF CHAMBER

Fiber Optic TxRx Pair

Field Monitor

Amplifier Research

FM7004

Laser Interface

Amplifier Research

FL7000

Pasternak

PE9128

Pasternak

PE9128

F.O Feedthru

Adapters

Fiber Optic Tx Rx Pair

Fiber Optic Power

FSV40 w/ N adapter

Main Computer

EMC32 Software

GPIB/Ethenet 

Controller

GPIB

Gore 

0SQ01Q011180-T/V

8324498

AH Systems

SAC-18G-3

Gore 0SQ01Q011180-T/V

8324499

LCom

CA-6NMNM025

Gore

0SQ01Q010787-T/V

8324497

Fiber Optic Tx Rx Pair

Ethernet Ethernet

Switch

Ethernet

Figure B.11.—RF Equipment Setup, Unloaded Chamber, 1 to 4 GHz 

NASA/TM—2014-218363 35 
Figure B.12.—RF Equipment Setup, Loaded Chamber, 1 to 4 GHz 

Signal Generator Direc. Coupler 

Power Meter

Agilent N1914A

& N8487A (2)

Tx Antenna

Spectrum Analyzer

Rohde & Schwarz Rx Antenna

Motor Controller 

Carousel AT11

E-Field Probe

Amplifier Research 

FL7040

Agilent E8257D

RF Amplifier

Amplifier Research

15S4G8AM2

Fairview Microwave

SM3085 Adapter

AR DC 7350A

Fwd Rev

CH A CH B

AH Systems

SAS-571

Pasternak

PE 9503 

Adapter (2)

F.O Feedthru

Adapter

GRC Tuner

Carousel 

Turntable

DC Block

Pasternack

PE8123

Attenuator

Pasternack

PE7017-20

AH Systems

SAS-571

SPF CHAMBER

Fiber Optic TxRx Pair

Field Monitor

Amplifier Research

FM7004

Laser Interface

Amplifier Research

FL7000

Pasternak

PE9128

Pasternak

PE9128

F.O Feedthru

Adapters

Fiber Optic Tx Rx Pair

Fiber Optic Power

FSV40 w/ N adapter

Main Computer

EMC32 Software

GPIB/Ethernet 

Controller

GPIB

Gore 

0SQ01Q011180-T/V

8324498

AH Systems

SAC-18G-3

Gore 0SQ01Q011180-T/V

8324499

LCom

CA-6NMNM025

Gore

0SQ01Q010787-T/V

8324497

Fiber Optic Tx Rx Pair

Ethernet Ethernet

Switch

Ethernet

Figure B.13.—RF Equipment Setup, 4 to 8 GHz

NASA/TM—2014-218363 36 
Signal Generator Direc. Coupler 

Power Meter

Agilent N1914A

& N8487A (2)

Tx Antenna

Spectrum Analyzer

Rohde & Schwarz Rx Antenna

Motor Controller 

Carousel AT11

E-Field Probe

Amplifier Research 

FL7040

Agilent E8257D

RF Amplifier

Amplifier Research

AR 10S6G18AM4

Fairview Microwave 

SM3085 Adapter

AR DC 7435A Fwd Rev

CH A CH B

AH Systems

SAS-571

Pasternak

PE9654 

Adapter (2)

F.O Feedthru

Adapter

GRC Tuner

Carousel 

Turntable

DC Block

Pasternack

PE8123

Attenuator

Pasternack

PE7017-20

AH Systems

SAS-571

SPF CHAMBER

Fiber Optic TxRx Pair

Field Monitor

Amplifier Research

FM7004

Laser Interface

Amplifier Research

FL7000

Pasternak

PE9128

Pasternak

PE9128

F.O Feedthru

Adapters

Fiber Optic Tx Rx Pair

Fiber Optic Power

FSV40 w/ N adapter

Main Computer

EMC32 Software

GPIB/Ethernet 

Controller

GPIB

Gore 

0SQ01Q011180-T/V

8324498

AH Systems

SAC-18G-3

Gore 0SQ01Q011180-T/V

8324499

LCom

CA-6NMNM025

Gore

0SQ01Q010787-T/V

8324497

Fiber Optic Tx Rx Pair

Ethernet Ethernet

Switch

Ethernet

Figure B.14.—RF Equipment Setup, 8 to 18 GHz 

Figure B.15.—RF Equipment Setup, 18 to 26 GHz 

NASA/TM—2014-218363 37 
Figure B.16.—RF Equipment Setup, 26.5 to 40 GHz 

NASA/TM—2014-218363 38 
Appendix C.—Relevant Equations For Chamber Loading Estimate 

C.1 Chamber Parameters 

V = Volume = 23,315 m3

S = Surface Area = 5,735 m2

Material = Aluminum Alloy 3003 

Aluminum 3003 Resistivity = 3.49u10-8 :-m 

V = Aluminum 3003 Conductivity = 2.865u107

 Mho/m 

P = Aluminum 3003 Permeability = 1.256665u10-6

Pr = Aluminum 3003 Relative Permeability = 1.000022 

Power required = 200 V/m = 106 W/m2

Calculation of Theoretical Chamber Q: 

Q = (3 * V ) / (2 * S * G * Pr) 

G = [ 2 / (2Sf * Po * Pr * V ]1/2

Calculation of Theoretical Required Transmit Power to Yield 200 V/m 

Pt = Transmit Power 

¢Sr2 = Scalar mean power density in the chamber = ( O * Q * Pt ) / ( 2 * S * V ) = 106 W/m2

Theoretical Chamber Reverberation Threshold 

Qthr = [( 4 * S ) / 3 ]2/3 * [ V1/3 / (2 * O )] 

NASA/TM—2014-218363 39 

Appendix D.—Vehicle Approximated Physical Characteristics 

D.1 Geometry 

The Orion CEV is comprised of an Outer Main Engine (OME), a Service Module (SM), a Crew 

Module (CM), and a Launch Abort System (LAS). The geometries were simplified for expediency, into 

the components shown in Figure D.1. As a result, the following parameters were calculated: 

Solid Vehicle, based on the dimensions of the Outer Mold Line (OML): 

Vveh_solid = 7.30 + 35.41 – 5.84 + 33.79 + 1.23 = 71.89 m3

Weight of the vehicle = 18,447 Kg (source: http://www.nasa.gov/pdf/402684main_M2140_orion_fs_rev2.pdf) 

Density of carbon fiber composite = 1600 Kg/m3

The worst case absorption would be if the vehicle were assumed to be 100 percent composite. In this 

case, the volume of composite material would equal the weight of the vehicle divided by the density of 

the composite 

Vvehicle = 18447 / 1600 = 11.53 m3

As a sanity check for this calculation, the ratio of composite to empty space is: 

11.53/71.89 to 1 – 11.53/71.89 = 16 : 84, which seems within reasonable bounds. 

Surface Area of the vehicle is: 

Sveh = 35 + 46.69 – 13.64 + 20.54 + 4.82 = 93.41 m2

CSave = Ave Cross Sectional Area # Volume / Height = 11.53 / (13.357+3.3+4.78+1.42) = 0.504 m2

D.2 Theoretical Electromagnetic Properties of Vehicle 

Loss Tangent = tan G = 1/Q = V / (ZH) 

Some assumptions were made about the relationships between vehicle properties and the loading 

factor Qvehicle. 

A value for loss tangent was found to be 0.06 at 2.45 GHz. The source for this value is 

http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=1711286. Backing out the dependency on 

frequency will allow calculation of the loss tangent across the frequency spectrum of interest: 

0.06 2 2.45 10 9.236 108 9 V H 
 
S
 u u . 

To calculate the loading of the chamber by the presence of the vehicle, the following relationship 

between vehicle volume and cross-sectional area to the overall chamber volume was assumed. 

Qvehicle D Vchamber   Vvehicle 
CSave

Qvehicle #    1 tan G > @ Vchamber Vvehicle 
CSave

NASA/TM—2014-218363 41 
Figure D.1.—Geometries Used for the CEV Model 

NASA/TM—2014-218363 42 
Appendix E.—Graphs of Calculated CEV Loading 

Figure E.1.—Loss Tangent of Carbon Based Resin Composite versus Frequency 

Figure E.2.—Theoretical Q of the CEV 

chamber vehicle

loaded 1 Q 1 Q

1 Q

 

NASA/TM—2014-218363 43 
Figure E.3.—Theoretical Q of the Chamber Loaded With CEV 

Figure E.4.—Theoretical Q of Empty Chamber, Vehicle, Loaded Chamber, and Threshold 

NASA/TM—2014-218363 44 
Figure E.5.—Comparison of Theoretical and Measured Q Values 

NASA/TM—2014-218363 45 

Appendix F.—Document History Log 

Status 

(Baseline/ 

Revision/ 

Canceled) 

Document 

Revision 

Effective 

Date 

Description 

Baseline - June 30, 2014 Late Baseline, for forward work with MPCV 

NASA/TM—2014-218363 47 

Appendix G.—Space Power Facility Reverberation 

Chamber Calibration Report 

Signature Page 

NASA/TM—2014-218363 49 

Appendix H.—Errata 

x After the calibration procedure was performed, the Spectrum Analyzer, Rhode & Schwarz

FSV40, Serial Number 100918, was sent to GRC Metrology for calibration. It was found that one

or more of the measured values were outside the data sheet specifications, specifically the DC

coupled RF attenuation near 40 GHz, and the Phase Noise with a 96 kHz carrier offset.

ż The RF attenuation at 10, 20, 30, and 40 dB all measured approximately –3 dB, and the limit

is –2.5 dB. The impact of this out-of-range attenuation would have to be analyzed.

ż The phase noise was over the limit of 115 dBc (1 Hz) by only 0.07 dBc (1 Hz). (The

measured value was 114.93 dBc (1 Hz).) It is doubtful that this out of range parameter had a

measureable impact on the chamber calibration.

NASA/TM—2014-218363 51