A.H. Systems SAS-551 User manual

A.H. Systems Model SAS-551 Passive MonopoleAntenna
©A.H. Systems inc. –REV E
1
SAS-551 Passive
Monopole Antenna
Operation Manual

A.H. Systems Model SAS-551 Passive MonopoleAntenna
©A.H. Systems inc. –REV E
2
TABLE OF CONTENTS
INTRODUCTION
3
SPECIFICATIONS
5
OPERATING INSTRUCTIONS
6
CALCULATIONS
9
CALIBRATION
10
CONVERSION FORMULAS
12
MAINTENANCE
13
WARRANTY
14

A.H. Systems Model SAS-551 Passive MonopoleAntenna
©A.H. Systems inc. –REV E
3
INTRODUCTION
Model
Frequency
Range
Part
Number
Description
SAS-551
9 kHz –40 MHz
2348
Passive Monopole Antenna

A.H. Systems Model SAS-551 Passive MonopoleAntenna
©A.H. Systems inc. –REV E
4
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 40C
Maximum relative humidity: 80% for temperatures up to 31C.
Decreasing linearly to 50% at 40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.

A.H. Systems Model SAS-551 Passive MonopoleAntenna
©A.H. Systems inc. –REV E
5
SPECIFICATIONS
GENERAL DESCRIPTION
The A.H. Systems passive monopole antenna is a general-purpose transmitting
antenna which cover the 10 KHz –40 MHz frequency range. Each unit comes
with a telescoping rod and ground plane. Review this manual and become
familiar with all safety markings and instructions.
ANTENNA SPECIFICATIONS
SAS-551 Monopole Antenna specifications:
Frequency Range ............................................................................9 kHz –40 MHz
Input Connector Type.......................................................................................BNC(f)
Mounting Base....................................................................................1/4-20 Tread(f)
Weight.............................................................................................................3.5 lbs.
Size (W x H x D) ...........................................18" x 18" x 41" (46 cm x 46 cm x 104 cm)

A.H. Systems Model SAS-551 Passive MonopoleAntenna
©A.H. Systems inc. –REV E
6
OPERATING INSTRUCTIONS
ASSEMBLY INSTRUCTIONS
To prepare the antenna for operation, attach the telescoping rod antenna
element to the top of the ground plane box.
Connect the rod antenna by pushing straight down on the female
connector on top of the amplifier. Do not apply excessive sideways force,
as this can cause the antenna center-pin to break.
SETUP INSTRUCTIONS
The ground plane can be mounted to any tripod with a 1/4-20 attaching stud.
Extend the rod antenna to 41" (104 cm) above the ground plane. Connect the
output BNC connector on the side of the antenna to the output of a 50 
generator or amplifier. Establish a ground connection to the ground plane if
required by the test specification.

A.H. Systems Model SAS-551 Passive MonopoleAntenna
©A.H. Systems inc. –REV E
7
GENERAL USE INSTRUCTIONS
The SAS-551 monopole antenna is a passive antenna designed to transmit
broadband electric fields. When used with the SAS-550-1B active monopole,
these antennas are the ideal solution for shielding effectiveness testing. This
antenna may also be used as a passive receive antenna for testing in areas
with high fields.
Each antenna is individually calibrated per ANSI C63.5 (ECSM) and comes with
a calibration certificate references the NIST traceable test equipment.
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.
Caution:
It is recommended to load the monopole input with 50 ohms or use a power
resistor (connected in parallel with the antenna) if the signal generator or power
amplifier used to drive the antenna requires a 50 ohm match. This requirement
is typical for antennas with short radiators (radiator length of λ/10 or less) and
that operate below 30 MHz.
The SAS-551 antenna by itself does not represent a 50-ohm load to the
signal source.
OPTIONAL EQUIPMENT
The following is a recommend accessory list for the SAS-551 Passive Monopole
Antenna:
ECF-10
The ECF-10 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-10 is used as a signal substitution
source when calibrating the active monopole antennas. Refer to the calibration
procedures below.
SAC-210

A.H. Systems Model SAS-551 Passive MonopoleAntenna
©A.H. Systems inc. –REV E
8
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.
Adapters
Need an Adapter? We stock those as well.

A.H. Systems Model SAS-551 Passive MonopoleAntenna
©A.H. Systems inc. –REV E
9
CALCULATIONS
EMISSIONS TESTING
Individual calibration data for the passive monopole 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V/meter.
Field Strength(dBuV/m) = SA(dBuV) + AF(dB/m) + cable loss (dB)
SA = Spectrum Analyzer or Receiver voltage reading
AF = Antenna Correction Factor
CL = Cable Loss in dB
IMMUNITY TESTING
For Immunity measurements, the generated electric field strength can be
calculated by:
FS = Approximate Field Strength in (V/m)
P = Power in watts
g = Numeric Gain
d = Distance in meters

A.H. Systems Model SAS-551 Passive MonopoleAntenna
©A.H. Systems inc. –REV E
10
CALIBRATION
Equivalent Capacitance
It is our recommendation to use a 12 pF for the ECSM fixture for an element height of 41” (1.04
meter) as per ANSI C63.5:2017 and CISPR 16-1-6:2017. Our telescoping rod with a BNC connector
that is supplied with the SAS-551 has an average radius of 2.223mm. The formula for calculating the
capacitance is (per ANSI C63.5:2017 and CISPR 16-1-6:2017):
Ca= (55.6 h) / (ln(h / a) –1) * (tan(2 πh /λ)) / (2 πh /λ)
Eq 1
where: h = actual length of the monopole element (adjusted to 1.04m), m
a = average radius of the antenna element (6.17mm), m
λ= wavelength in meters
Ca= capacitance of the dummy load
NOTE - Other fixtures with different capacitance are available as an option.
Effective Height Calculation
The correction factor for the calibration is dependent on the effective height of the monopole. The
effective height calculation is:
he = (λ/ 2π)* tan(2 πh /λ)
Eq. 2
where:
λ= wavelength in meters
h= Telescoping element height in meters
Examples:
•For a 41” (1.04 Meter) length, the effective height would be 0.52 meters (up to approximately
2 MHz) and the correction factor should be 20*Log(0.52) = -5.68 dB.
•For a 1 Meter length, the effective height would be 0.5 meters (up to approximately 2 MHz)
and the correction factor should be 20*Log(0.5) = -6.02 dB.

A.H. Systems Model SAS-551 Passive MonopoleAntenna
©A.H. Systems inc. –REV E
11
Active Monopole Calibration
The antenna factor for the rod antenna shall be determined by measuring the signal transfer
characteristics with the matching device and assuming that the antenna is a short monopole with an
infinite ground plane. Set up the monopole to be calibrated and the test equipment per Figure 3.
Allow all equipment to warm up for 30 minutes.
* Also referred to as a Dummy Antenna.
Figure 1
1) With the equipment connected as shown in Figure 1, measure the drive signal voltage VDin
dBV at the T-connector (A).
* Also referred to as a Dummy Antenna.
Figure 2
2) Leaving the RF output of the signal generator unchanged, transfer the 50 termination to
the T-connector (A) and transfer the receiver input cable to the signal output port (B).
Measure the output signal voltage VLin dBV.
3) The antenna factor (in dB) is calculated by the following equation.
AF(dB) = VD–VL–(20*Log(he))
Eq.3
NOTES –If the VSWR of the receiver or signal generator is low, pads (attenuators) may not be
needed or reduced to 6dB or 3dB. The signal generator does not need to be calibrated, but it shall
be stable per manufacturers recommendations. The 50 termination and attenuators shall have
low VSWR. The spectrum analyzer shall be calibrated and have low VSWR.

A.H. Systems Model SAS-551 Passive MonopoleAntenna
©A.H. Systems inc. –REV E
12
TYPICAL CONVERSION FORMULAS
LOG -> LINEAR VOLTAGE
FIELD STRENGTH & POWER DENSITY
dBV to Volts
V = 10 ((dBV –120) / 20)
dBV/m to V/m
V/m = 10 (((dBV/m) -120) / 20)
Volts to dBV
dBV = 20 log(V) + 120
V/m to dBV/m
dBV/m = 20 log(V/m) + 120
dBV to Volts
V = 10 (dBV / 20)
dBV/m to dBmW/m2
dBmW/m2= dBV/m –115.8
Volts to dBV
dBV = 20log(V)
dBmW/m2to dBV/m
dBV/m = dBmW/m2+ 115.8
dBV to dBV
dBV = dBV +120
dBV/m to dBA/m
dBA/m = dBV/m –51.5
dBV to dBV
dBV = dBV - 120
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 = 10 (dBA / 20)
dBpT to dBA/m
dBA/m = dBpT –2
A to dBA
dBA = 20 log(A)
W/m2to V/m
V/m = SQRT(W/m2* 377)
dBA to A
A = 10 (dBA / 20)
V/m to W/m2
W/m2= (V/m)2/ 377
A to dBA
dBA = 20log(A)
T to A/m
A/m = T / 1.25
dBA to dBA
dBA = dBA + 120
A/m to T
T = 1.25 * A/m
dBA to dBA
dBA = dBA -120
E-FIELD ANTENNAS
LOG -> LINEAR POWER
Correction Factor
dBV/m = dBV + AF
dBm to Watts
W = 10((dBm –30)/10)
Field Strength
V/m = 30 * watts * Gain numeric
meters
Watts to dBm
dBm = 10log(W) + 30
Required Power
Watts = (V/m * meters)2
30 * Gain numeric
dBW to Watts
W = 10(dBW / 10)
LOOP ANTENNAS
Watts to dBW
dBW = 10log(W)
Correction Factors
dBA/m = dBV + AF
dBW to dBm
dBm = dBW + 30
Assumed E-field for
shielded loops
dBV/m = dBA/m + 51.5
dBm to dBW
dBW = dBm - 30
dBpT = dBV + dBpT/V
TERM CONVERSIONS
dBm to dBV
dBV = dBm + 107 (50)
dB  V = dBm + 10log(Z) + 90
CURRENT PROBES
dBV to dBm
dBm = dBV –107 (50)
dBm = dB  V –10log(Z) –90
Correction Factor
dBA = dBV –dB(ohm)
dBm to dBA
dBA = dBm –73 (50)
dB  A = dBm –10log(Z) + 90
Power needed for injection probe given voltage(V) into
50load and Probe Insertion Loss (IL)
dBA to dBm
dBm = dBA + 73 (50)
dBm = dB  A + 10log(Z) –90
Watts = 10 ((IL+ 10log(V2/50))/10)
dBA to dBV
dBV = dBA + 34 (50)
dB  V = dB  A + 20log(Z)
dBV to dBA
dBA = dBV –34 (50)
dB  A = dB  V –20log(Z)

A.H. Systems Model SAS-551 Passive MonopoleAntenna
©A.H. Systems inc. –REV E
13
MAINTENANCE
To ensure reliable and repeatable long-term performance, annual re-
calibration of your active monopole preamplifier by A.H. Systems’
experienced technicians is recommended. Our staff can recalibrate almost
any type or brand of antenna. For more information about our calibration
services or to place an order for antenna calibration, visit our website at
www.AHSystems.com or call [phone].

A.H. Systems Model SAS-551 Passive MonopoleAntenna
©A.H. Systems inc. –REV E
14
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.