ETS-Lindgren 3148 User Manual Download Page 9

MODEL 3148 LOG-PERIODIC DIPOLE ARRAY ANTENNA   

Application 

© EMC TEST SYSTEMS, L.P. – SEPTEMBER 2002 

 

5

 

REV C – PN 399239 

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 

V

 is 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 

d

 can be 

approximated by  
 
 

 

d

pg

m

V

E

30

)

/

(

=

 
where 

d

 is in meters, 

g

 is the numeric gain (10 

G[dB]/10

, see attached 

calibration data), and 

P

 is antenna net input power in watts. An 

estimate of the power required in free space condition for any field 
strength 

E

 can 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) = E

2

 P(1 V/m). 

 

Summary of Contents for 3148

Page 1: ... EMC TEST SYSTEMS L P SEPTEMBER 2002 REV C PN 399239 Model 3148 93148 Log Periodic Dipole Array Antenna MANUAL ...

Page 2: ...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 Support ets lindgren com http www ets lindgren com USA 1301 Arrow Point Dr Cedar Park TX 78613 P O Box 80589 Austin TX 78708 0589 Tel 512 531 6400 Fax 51...

Page 3: ... 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 ...

Page 4: ...MODEL 3148 LOG PERIODIC DIPOLE ARRAY ANTENNA EMC TEST SYSTEMS L P SEPTEMBER 2002 REV C PN 399239 ...

Page 5: ...s 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 perf...

Page 6: ...cted 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 ph...

Page 7: ...ing 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 connecto...

Page 8: ...y 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 ...

Page 9: ... 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 V is 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 ...

Page 10: ...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 genera...

Page 11: ...MODEL 3148 LOG PERIODIC DIPOLE ARRAY ANTENNA Typical Data EMC TEST SYSTEMS L P SEPTEMBER 2002 7 REV C PN 399239 TYPICAL DATA ...

Page 12: ...Typical Data MODEL 3148 LOG PERIODIC DIPOLE ARRAY ANTENNA 8 EMC TEST SYSTEMS L P SEPTEMBER 2002 REV C PN 399239 ...

Page 13: ...MODEL 3148 LOG PERIODIC DIPOLE ARRAY ANTENNA Typical Data EMC TEST SYSTEMS L P SEPTEMBER 2002 9 REV C PN 399239 ...

Page 14: ...male 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 an...

Page 15: ...r 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 v Normal wear and tear of materials v Consumable items such as fuses batteries etc v Products that have been improperly installed maintained or used v Products whi...

Reviews: