ETS-Lindgren 3148 User manual

©EMC TEST SYSTEMS, L.P. –SEPTEMBER 2002 REV C –PN 399239
Model 3148 & 93148
Log-Periodic Dipole
Array Antenna
MANUAL

MODEL 3148 LOG-PERIODIC DIPOLE ARRAY ANTENNA
© EMC TEST SYSTEMS, L.P. –SEPTEMBER 2002
REV C –PN 399239
EMC Test Systems, L.P. reserves the right to make changes to any products herein to improve functioning,
design, or for any other reason. Nothing contained herein shall constitute EMC Test Systems, L.P.
assuming any liability whatsoever arising out of the application or use of any product or circuit described
herein. EMC Test Systems, L.P. does not convey any license under its patent rights or the rights of others.
© Copyright 2002 by EMC Test Systems, L.P. All Rights Reserved.
No part of this document may be copied by any means
without written permission from EMC Test Systems, L.P.
E-MAIL & INTERNET
[e-mail]
http://www.ets-lindgren.com
USA
1301 Arrow Point Dr., Cedar Park, TX 78613
P.O. Box 80589, Austin, TX 78708-0589
Tel [phone] Fax [phone]
FINLAND
Euroshield OY
Mekaanikontie 1
27510, Eura, Finland
Tel [phone]
Fax [phone]
SINGAPORE
Lindgren RF Enclosures Asia-Pacific
87 Beach Road
#06-02 Chye Sing Building
Singapore 189695
Tel [phone] Fax [phone]

MODEL 3148 LOG-PERIODIC DIPOLE ARRAY ANTENNA
© EMC TEST SYSTEMS, L.P. –SEPTEMBER 2002
REV C –PN 399239
Table of Contents
INTRODUCTION.................................................................................................................................. 1
STANDARD CONFIGURATION......................................................................................................... 2
OPTIONS............................................................................................................................................... 2
MOUNTING INSTRUCTIONS............................................................................................................. 3
ANTENNA SUPPORTS ............................................................................................................................. 3
EMISSIONS AND IMMUNITY............................................................................................................ 4
APPLICATION...................................................................................................................................... 5
TYPICAL DATA.................................................................................................................................... 7
SPECIFICATIONS.............................................................................................................................. 10
ELECTRICAL ....................................................................................................................................... 10
PHYSICAL ........................................................................................................................................... 10
MAINTENANCE................................................................................................................................. 10
WARRANTY........................................................................................................................................ 11

MODEL 3148 LOG-PERIODIC DIPOLE ARRAY ANTENNA
© EMC TEST SYSTEMS, L.P. –SEPTEMBER 2002
REV C –PN 399239

MODEL 3148 LOG-PERIODIC DIPOLE ARRAY ANTENNA Introduction
© EMC TEST SYSTEMS, L.P. –SEPTEMBER 2002 1
REV C –PN 399239
INTRODUCTION
The ETS-Lindgren Model 3148 Log Periodic Dipole Array is a
linearly polarized, broadband antenna designed to operate over the
frequency range of 200 MHz to 2 GHz. The choice of scaling
factors, the various diameters of each element, and the center-to
center spacing of the booms are such that excellent VSWR
characteristics are obtained throughout the operating frequency
range (See Model 3148 VSWR data in the “Typical Data” section
of this manual). The precise design of the feed and positioning of
the elements on the boom yield optimum phase relationship. This
causes the active region, at any given frequency, to propagate RF
energy towards the smaller elements leaving the elements behind it
electrically dead.
The Model 3148 antenna fully satisfies CISPR-16 cross-
polarization rejection requirement, and has better than 20 dB cross-
polarization rejection below 1000 MHz. The constant gain of the
antenna yields an antenna factor which varies linearly with
frequency as shown in the “Typical Data” section of this manual.
The variation is smooth; therefore, accurate interpolation of
performance between specified frequency points is simple.
The Model 3148 Log-Periodic antenna is constructed of
lightweight, corrosion-resistant aluminum, providing years of
trouble-free indoor and outdoor service.
The antenna is provided with an integral mount and the necessary
attachments to mount the antenna to either a tripod (with a ¼-20
threaded mount) or an ETS-Lindgren antenna mast. Individual
antenna calibration data is included with each antenna.
The Model 93148 is a non-characterized version of the Model
3148. Should calibration/characterization be desired please contact
our calibration department.

Standard Configuration MODEL 3148 LOG-PERIODIC DIPOLE ARRAY ANTENNA
2© EMC TEST SYSTEMS, L.P. –SEPTEMBER 2002
REV C –PN 399239
STANDARD CONFIGURATION
•Antenna
•Manual
•Individually calibrated at 1m per SAE ARP 958 and 3 and 10
m per ANSI C63.5. Actual antenna factors and a signed
Certificate of Calibration Conformance included.
OPTIONS
Support Rod: Antenna mount with insert configured to accept
EMCO or other tripodswith standard ¼ in x 20 threads.
Tripods: ETS-Lindgren offers two nonmetallic, non-reflective
tripods for use at both indoor and outdoor EMC test sites.
The Model 4-TR, constructed of linen phenolic and delrin, is
designed with an adjustable center post for precise height
adjustments. Maximum height for the 4-TR is 2.0 m (80.0 in),
while minimum height is 94 cm (37.0 in). This tripod can support
up to an 11.8 kg (26.0 lb) load.
The 7-TR tripod has several different configurations, including
options for manual or pneumatic polarization. This tripod provides
increased stability for physically large antennas. Its unique design
allows for quick assembly/disassembly and convenient storage.
Quick height adjustment and locking wheels provide ease of use
during testing. This tripod can support up to a 13.5 kg (30.0 lb)
load. For the 7-TR series, maximum height is 2.17 m (85.8 in),
with a minimum height of .8 m (31.8 in). The 7-TR is constructed
of PVC and fiberglass components.

MODEL 3148 LOG-PERIODIC DIPOLE ARRAY ANTENNA Mounting Instructions
© EMC TEST SYSTEMS, L.P. –SEPTEMBER 2002 3
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MOUNTING INSTRUCTIONS
The Model 3148 Antenna consists of the following:
1 ea. Log Periodic Dipole Array Antenna
1 ea. Log Periodic Antenna Adaptor
1 ea. Thread Insert for the Adaptor
ANTENNA SUPPORTS
The bottom side of the antenna adaptor has a 7/8 in. by 14 threaded
receptacle for mounting the adaptor on a tower or tripod, if this is
not the desired receptacle size, thread the 1/4 in. by 20 thread insert
into the adaptor. Take care not to cross thread this connection as
permanent damage to the adaptor and insert could occur.
Next attach the antenna adaptor to the tower or tripod that will be
used for testing. This can be accomplished by threading the
mounting knob or threaded connector into the adaptor.
To mount the 3148 antenna, slide the adapter between the
shoulders of the mounting bracket on the antenna. One side of the
mounting bracket is fitted with a hex nut that in conjunction with

Emissions and Immunity MODEL 3148 LOG-PERIODIC DIPOLE ARRAY ANTENNA
4© EMC TEST SYSTEMS, L.P. –SEPTEMBER 2002
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the knob provided will secure the assembly together. Thread the
knob through the mounting bracket and adapter so that the knob
threads through the hex nut last. Carefully tighten the knob to
secure the antenna in place.
EMISSIONS AND IMMUNITY
The picture and diagrams below illustrate the convenient label that
pinpoints the antenna’s centerline and tip, serving as a reminder of
where to perform measurements.

MODEL 3148 LOG-PERIODIC DIPOLE ARRAY ANTENNA Application
© EMC TEST SYSTEMS, L.P. –SEPTEMBER 2002 5
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APPLICATION
Install the Model 3148 on an ETS-Lindgren tripod or antenna mast
adapter. Connect an N-type coaxial cable from the antenna
connector to a generator (immunity) or receiver (emissions). Both
horizontal and vertical polarization are easily accomplished when
the Model 3148 is mounted on a tower or tripod. Contact with any
metallic or non-metallic structure can capacitively load the antenna
which may cause inconsistent results. Therefore, care must be
taken to ensure that no part of the dipole elements are in contact
with the tripod or tower, particularly in vertically-polarized tests.
Where possible, run the feed cable straight at least 1 meter or more
back from the Model 3148 before dropping vertically.
For emissions measurements, electric field strength in db[V/m] is
obtained from
E(dBV/m)=V(dBV)+AF(dB1/m)+α(dB),
Where Vis the receiver or spectrum analyzer voltage reading, AF
is antenna factor (see attached calibration data), and α is cable loss
in dB, if cable losses are non-negligible. For immunity testing, the
electric field strength generated at a distance dcan be
approximated by
d
pg
mVE 30 )/(=,
where dis in meters, gis the numeric gain (10 G[dB]/10, see attached
calibration data), and Pis antenna net input power in watts. An
estimate of the power required in free space condition for any field
strength Ecan be obtained from the forward power graphs in the
“Typical Data” section, which shows power required in watts to
generate 1 V/m. For any other field strength not shown, multiply
the power in watts by the desired E-field squared, or
P(E V/m) = E2P(1 V/m).

Application MODEL 3148 LOG-PERIODIC DIPOLE ARRAY ANTENNA
6© EMC TEST SYSTEMS, L.P. –SEPTEMBER 2002
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Actual transmitted field strength should be verified using an
ETS-Lindgren Model HI-6005 Electric Field Probe or equivalent.
For IEC/EN 31000-4-3 type testing, the antenna tip can be placed
at any distance between 1 and 3 meters from the EUT as long as
the front face plane is illuminated according to the –0, +6 dB
uniform field specifications. It is usually necessary to place RF
absorbing material between the EUT and antenna to suppress
ground plane reflection to ensure the field uniformly, or conduct
the immunity test in a fully-lined anechoic room. In general, closer
distances require less power to create a given field strength.

MODEL 3148 LOG-PERIODIC DIPOLE ARRAY ANTENNA Typical Data
© EMC TEST SYSTEMS, L.P. –SEPTEMBER 2002 7
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TYPICAL DATA

Typical Data MODEL 3148 LOG-PERIODIC DIPOLE ARRAY ANTENNA
8© EMC TEST SYSTEMS, L.P. –SEPTEMBER 2002
REV C –PN 399239

MODEL 3148 LOG-PERIODIC DIPOLE ARRAY ANTENNA Typical Data
© EMC TEST SYSTEMS, L.P. –SEPTEMBER 2002 9
REV C –PN 399239

Specifications MODEL 3148 LOG-PERIODIC DIPOLE ARRAY ANTENNA
10 © EMC TEST SYSTEMS, L.P. –SEPTEMBER 2002
REV C –PN 399239
SPECIFICATIONS
ELECTRICAL
Frequency Range 200 MHz –2 GHz
VSWR Ratio 1.2:1 average
2.0:1 maximum
Maximum Continuous Power 1 kW
Peak Power 1.3 kW
Input Impedance (Nominal) 50 ohms
Symmetry +/-0.5 dB
Cross-Polarization rejection Better than 20 dB below 1000
MHz
Connector Type N female
PHYSICAL
Height 6.4 cm (2.5 in )
Width 85.6 cm (33.7 in)
Depth (length) 73.7 cm (29.0 in)
Weight 2.0 kg (4.5 lb)
MAINTENANCE
To ensure reliable and repeatable long-term performance, annual
recalibration of your antennas by ETS-Lindgren’s experienced
technicians is recommended. Our staff can recalibrate almost any
type or brand of antenna. Please call to receive a service order
number prior to sending an antenna to us for calibration.
For more information about our calibration services or to place an
order for antenna calibration visit our calibration website at
http://www.antennacalibration.com/.

MODEL 3148 LOG-PERIODIC DIPOLE ARRAY ANTENNA Warranty
© EMC TEST SYSTEMS, L.P. –SEPTEMBER 2002 11
REV C –PN 399239
WARRANTY
EMC Test Systems, L.P., hereinafter referred to as the Seller, warrants that standard EMCO
products are free from defect in materials and workmanship for a period of two (2) years from
date of shipment. Standard EMCO Products include the following:
vAntennas, Loops, Horns
vGTEM cells, TEM cells, Helmholtz Coils
vLISNs, PLISNs, Rejection cavities & Networks
vTowers, Turntables, Tripods & Controllers
vField Probes, Current Probes, Injection Probes
If the Buyer notifies the Seller of a defect within the warranty period, the Seller will, at the Seller’s
option, either repair and/or replace those products that prove to be defective.
There will be no charge for warranty services performed at the location the Seller designates.
The Buyer must, however, prepay inbound shipping costs and any duties or taxes. The Seller will
pay outbound shipping cost for a carrier of the Seller’s choice, exclusive of any duties or taxes. If
the Seller determines that warranty service can only be performed at the Buyer’s location, the
Buyer will not be charged for the Seller’s travel related costs.
This warranty does not apply to:
vNormal wear and tear of materials
vConsumable items such as fuses, batteries, etc.
vProducts that have been improperly installed, maintained or used
vProducts which have been operated outside the specifications
vProducts which have been modified without authorization
vCalibration of products, unless necessitated by defects
THIS WARRANTY IS EXCLUSIVE. NO OTHER WARRANTY, WRITTEN OR ORAL, IS
EXPRESSED OR IMPLIED, INCLUDING BUT NOT LMITED TO, THE IMPLIED WARRANTIES
OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. THE REMEDIES
PROVIDED BY THIS WARRANTY ARE THE BUYER’S SOLE AND EXCLUSIVE REMEDIES.
IN NO EVENT IS THE SELLER LIABLE FOR ANY DAMAGES WHATSOEVER, INCLUDING
BUT NOT LIMITED TO, DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL
DAMAGES, WHETHER BASED ON CONTRACT, TORT, OR ANY OTHER LEGAL THEORY.
Note: Please contact the Seller’s sales department for a Return Materials Authorization (RMA)
number before shipping equipment to us.