ETS-Lindgren 3144 Log Periodic Dipole Array - Manual (Page 21)

5.0 Application
Before connecting any components, follow the
safety information in the ETS-Lindgren
Product Information Bulletin included with your
shipment.
After mounting the Model 3144 Log Periodic Dipole Array Antenna onto 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 polarizations are easily accomplished when the
Model 3144 is mounted onto a tower or tripod. Due to the length of the low
frequency elements, verify element clearance prior to switching the antenna to
vertical polarization. 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 is in contact with
the tripod or tower, particularly in vertically-polarized tests. Where possible, run
the feed cable straight at least one meter or more back from the Model 3144
before dropping vertically.
For emissions measurements, electric field strength in db[V/m] is obtained from:
E(dB[V/m])=V(dB[V])+AF(dB[1/m])+ α(dB)
V = the receiver or spectrum analyzer voltage reading
AF = antenna factor
α
= cable loss in dB, if cable losses are non-negligible
Application | 21