A.H. Systems EHA-51B User manual

A.H. Systems Model EHA-51B Active Monopole and Loop Antenna
EHA-51B Active
Monopole and Loop Antenna
Operation Manual
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A.H. Systems Model EHA-51B Active Monopole and Loop Antenna
TABLE OF CONTENTS
Introduction .....................................................................3
Specifications..................................................................5
Operating Instructions ....................................................7
Recommended Accessories .........................................1
Calculations ..................................................................11
Antenna Formulas ........................................................12
Maintenance..................................................................13
Warranty .......................................................................14
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A.H. Systems Model EHA-51B Active Monopole and Loop Antenna
INTRODUCTION
Model
Frequency
Range
Part
Number Description
EHA-51B 1 kHz – 3 MHz 2661 Active 12” Loop/Monopole Antenna
INCLUDED EQUIPMENT
•Amplifier/matching base unit
•12” shielded loop antenna
•41” telescoping rod antenna element
•battery charger
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A.H. Systems Model EHA-51B Active Monopole and Loop Antenna
INTENDED PURPOSES
This equipment is intended for general laboratory use in a wide variety of industrial
and scientific applications and designed to be used in the process of generating,
controlling and measuring high levels of electromagnetic Radio Frequency (RF)
energy. It is the responsibility of the user to assure that the device is operated in a
location which will control the radiated energy such that it will not cause injury and will
not violate regulatory levels of electromagnetic interference.
RANGE OF ENVIRONMENTAL CONDITIONS
This equipment is designed to be safe under the following environmental conditions:
Indoor use
Altitude: up to 2 km
Temperature: 5 C to 4  C
Maximum relative humidity: 8 % for temperatures up to 31 C.
Decreasing linearly to 5 % at 4  C
Pollution degree 2: Normally non-conductive with occasional
condensation.
While the equipment will not cause hazardous condition over this environmental
range, performance may vary.
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A.H. Systems Model EHA-51B Active Monopole and Loop Antenna
SPECIFICATIONS
GENERAL DESCRIPTION
The A.H. Systems EHA-51B Antenna is an active, general-purpose, receive-
only antenna that covers 1 KHz - 6 MHz. This antenna has a switchable front
end for receiving as a monopole or loop antenna.
As a monopole antenna it is ideal for instantaneous bandwidth scanning
(without tuning) of electric fields in its frequency range and can drive any
receiver with 5 -ohm input impedance.
The EHA-51B is also an active receive only loop antenna for magnetic field
testing. This loop antenna is ideal for emissions testing and has a balanced
Faraday shield to reduce the E-field response for a pure magnetic field
measurement. It is suitable for MIL-STD, VDE, and TEMPEST testing, with
reliable, repeatable measurements.
Review this manual and become familiar with all safety markings and
instructions.
ANTENNA SPECIFICATIONS
EHA-51B Monopole/Loop Antenna specifications:
Frequency Range ....................................................1 kHz – 3 MHz
Impedance ...........................................................................5 ohms
Output Connector Type ..........................................................BNC(f)
Mounting ....................................................................1/4-2 Tread(f)
Weight ...................................................................2.5 lbs. (1.13 kg)
Loop Diameter ..............................................................12" (3 .5cm)
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A.H. Systems Model EHA-51B Active Monopole and Loop Antenna
TYPICAL CORRECTION FACTOR
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A.H. Systems Model EHA-51B Active Monopole and Loop Antenna
OPERATING INSTRUCTIONS
ASSEMBLY INSTRUCTIONS
To prepare the antenna for operation, select the appropriate antenna switch
on the side of the impedance matching/amplifier base and attached the
corresponding antenna element. The telescoping rod antenna element will
require a BNC(f) to N(m) adapter.
SETUP INSTRUCTIONS
The antenna can be mounted to any tripod with a 1/4-2 attaching stud.
Connect the output BNC connector on the side of the impedance matching
amplifier base to the input of a 5  analyzer or receiver.
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A.H. Systems Model EHA-51B Active Monopole and Loop Antenna
GENERAL USE INSTRUCTIONS
The EHA-51B loop antenna is an active loop designed to perform magnetic
field and shielding effectiveness testing. The loop antenna has a balanced
Faraday shield to reduce the E-field response for a pure magnetic field
measurement.
Each antenna is individually calibrated per IEEE 291-1991 and comes with a
calibration certificate references the NIST traceable test equipment. Initially
the antenna comes with a 1 year calibration interval, however depending on
the type of use and standards that the antenna is being used, this interval can
be adjusted.
The calibration tables shown provide a listing of the frequency of operation
and its antenna factor in dB/m. The field strength is the receiver voltage in
dBV plus the antenna factor (refer to the antenna factor calibration) plus any
cable loss. When making a measurement, mount the antenna on an
appropriate mast or tripod with the plane of the loop antenna facing the DUT.
SHIELDING EFFECTIVNESS TESTING
Both the EHA-51B with the loop antenna element attached and the SAS-564
loop antenna can be used for shielding effectiveness testing. The EHA-51B is
used as the receive antenna and should be connect to an analyzer or
receiver, where the SAS-564 Loop antenna is a passive loop antenna used to
transmit.
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A.H. Systems Model EHA-51B Active Monopole and Loop Antenna
CHARGING THE BATTERY
Position the input voltage selector to the proper voltage (either 11 – 12 Vac,
6 Hz or 22 – 24 Vac, 5 Hz). Be sure to check the available voltage and
adjust the voltage selector as needed before use. The amplifier ON-OFF
switch must be in the OFF/CHARGE position to charge the battery. Every
hour of charge will result in two hours of operation for up to 1 hours of
charging. Charging for up to 24 hours will not damage the battery. Using the
battery charger to operate the amplifier directly is not recommended.
REPLACING THE BATTERIES
Remove the four 6-32 flat head screws from the bottom of the base unit.
Disconnect the battery lead from the PC card. Re-connect the lead from the
new battery pack assembly to the PC card. Snug the four 6-32 flat head
screws.
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A.H. Systems Model EHA-51B Active Monopole and Loop Antenna
RECOMMENDED ACCESSORIES
The following is a recommend accessory list for the EHA-51B Active
Monopole/Loop Antenna:
ECF-10
The ECF-1 is an equivalent capacitance fixture constructed per IEEE 291
and ARP 958. This is an indispensable tool used for gain adjustment and
calibration of the active monopole antennas. The ECF-1 is used as a signal
substitution source when calibrating the active monopole antennas.
SAC-461F
The SAC-461F is a cable kit required by MIL-STD 461F that contains the
appropriate ferrite bead and floor mounting bracket.
SAS-564
The SAS-564 has an input handling capability up to 5 Watts and
rugged design which makes this loop antenna excellent for immunity
and shielding effectiveness testing.
SAC-210
Standard 3 meter BNC(m) to BNC(m) RF cable made with RG-58. Optional
ferrite loading and custom lengths can be made to your specifications. Other
cable types available upon request.
Tripod
The ATU-51 wooded Tripod comes with a spring loaded 1/4-2 male thread for
mounting the SAS-563B Loop antenna.
Adapters
Need an Adapter? We stock those as well.
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A.H. Systems Model EHA-51B Active Monopole and Loop Antenna
CALCULATIONS
E ISSIONS TESTING
Individual calibration data for the active loop antenna is supplied to comply
with various emissions test requirements. For emissions measurements, add
antenna factor plus cable loss to receiver reading in dBV to convert to field
strength in dBA/meter.
Field Strength(dBuA/m) = SA(dBuV) + AF(dB/m) + cable loss (dB)
SA = Spectrum Analyzer or Receiver voltage reading
MAF = Magnetic Antenna Correction Factor
CL = Cable Loss in dB
Fictitious electric field strength can be calculated by the following:
dBV/m = dBA/m + 51.5
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A.H. Systems Model EHA-51B Active Monopole and Loop Antenna
TYPICAL ANTENNA FORMULAS
LOG -> LINEAR VOLTAGE FIELD STRENGTH & POWER DENSITY
dBV to Volts V = 1 ((dBV – 12 ) / 2 ) dBV/m to V/m V/m = 1 (((dBV/m) -12 ) / 2 )
Volts to dBV dBV = 2 log(V) + 12 V/m to dBV/m dBV/m = 2 log(V/m) + 12
dBV to Volts V = 1 (dBV / 2 ) dBV/m to dBmW/m2dBmW/m2 = dBV/m – 115.8
Volts to dBV dBV = 2 log(V) dBmW/m2 to dBV/m dBV/m = dBmW/m2 + 115.8
dBV to dBV dBV = dBV +12 dBV/m to dBA/m dBA/m = dBV/m – 51.5
dBV to dBV dBV = dBV - 12 dBA/m to dBV/m dBV/m = dBA + 51.5
LOG -> LINEAR CURRENT dBA/m to dBpT DBpT = dBA/m + 2
dBA to uA A = 1 (dBA / 2 ) dBpT to dBA/m dBA/m = dBpT – 2
A to dBA dBA = 2 log(A) W/m2 to V/m V/m = SQRT(W/m2 * 377)
dBA to A A = 1 (dBA / 2 ) V/m to W/m2W/m2 = (V/m)2 / 377
A to dBA dBA = 2 log(A) T to A/m A/m = T / 1.25
dBA to dBA dBA = dBA + 12 A/m to TT = 1.25 * A/m
dBA to dBA dBA = dBA -12 E-FIELD ANTENNAS
LOG -> LINEAR POWER Correction Factor dBV/m = dBV + AF
dBm to Watts W = 1 ((dBm – 3 )/1 ) Field Strength V/m = 3 * watts * Gain numeric
meters
Watts to dBm dBm = 1 log(W) + 3 Required Power Watts = (V/m * meters)2
3 * Gain numeric
dBW to Watts W = 1 (dBW / 1 ) LOOP ANTENNAS
Watts to dBW dBW = 1 log(W) Correction Factors dBA/m = dBV + AF
dBW to dBm dBm = dBW + 3 Assumed E-field for
shielded loops
dBV/m = dBA/m + 51.5
dBm to dBW dBW = dBm - 3 dBpT = dBV + dBpT/V
TER CONVERSIONS
dBm to dBVdBV = dBm + 1 7 (5 )
dB  V = dBm + 10log(Z) + 90
CURRENT PROBES
dBV to dBm dBm = dBV – 1 7 (5 )
dBm = dB  V – 10log(Z) – 90
Correction Factor dBA = dBV – dB(ohm)
dBm to dBA dBA = dBm – 73 (5 )
dB  A = dBm – 10log(Z) + 90
Power needed for injection probe given voltage(V) into
5  load and Probe Insertion Loss (IL)
dBA to dBm dBm = dBA + 73 (5 )
dBm = dB  A + 10log(Z) – 90
Watts = 1 ((IL + 1 log(V2/5 ))/1 )
dBA to dBV dBV = dBA + 34 (5 )
dB  V = dB  A + 20log(Z)
dBV to dBA dBA = dBV – 34 (5 )
dB  A = dB  V – 20log(Z)
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A.H. Systems Model EHA-51B Active Monopole and Loop Antenna
MAINTENANCE
To ensure reliable and repeatable long-term performance,
annual re-calibration of your active loop preamplifier by A.H.
Systems’ experienced technicians is recommended. Our staff
can recalibrate almost any type or brand of antenna.
Repair maintenance is not recommended in the field. The
antenna should be returned to A.H. Systems.
For more information about our calibration services or to place
an order for antenna calibration, visit our website at
www.AHSystems.com or call (818) 998- 223.
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A.H. Systems Model EHA-51B Active Monopole and Loop Antenna
WARRANTY INFORMATION
A.H. Systems Inc., warrants that our Antennas, Sensors and Probes will be free from
defects in materials and workmanship for a period of three (3) years. All other
products delivered under contract will be warranted for a period of two (2) years.
Damage caused by excessive signals at the product's input is not covered under the
warranty. A.H. Systems' obligation under this warranty shall be limited to repairing or
replacing, F.O.B. Chatsworth, California, each part of the product which is defective,
provided that the buyer gives A.H. Systems notice of such defect within the warranty
period commencing with the delivery of the product by A.H. Systems.
The remedy set forth herein shall be the only remedy available to the buyer, and in no
event shall A.H. Systems be liable for direct, indirect, incidental or consequential
damages.
This warranty shall not apply to any part of the product which, without fault of A.H.
Systems has been subject to alteration, failure caused by a part not supplied by A.H.
Systems, accident, fire or other casualty, negligence, misuse or normal wear of
materials.
Except for the warranty set forth above, there are no other warranties, expressed or
implied, with respect to the condition of the product or it's suitability for the use
intended for them by the buyer.
For prompt service, please contact our service department for a Return Material
Authorization Number before shipping equipment back to us.
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