ETS-Lindgren 3142B BiConiLog Antenna (Archived) User Manual

Page 6

Introduction

MODEL 3142B BICONILOG™ ANTENNA

suspended horizontally back from the antenna at least 1

meter before any vertical drop.

The antenna has a mounting bracket and 1/4X20 UNC

knob for attaching to an ETS-Lindgren tripod or tower

adapter. Individual antenna factors and gain calibration data

is included with each antenna.

The Model 3142B optional end plates (Part Number

106572) are available to improve gain for immunity testing.

This option consists of two end plates that are easily

attached and detached by hand using captive screw knobs.

When the end plates are attached it creates a T shaped bow-

tie element.

For any dipole–type antenna to transmit or receive energy

most efficiently, its length must be nearly a half

wavelength, which is about 4.6 meters long at 30 MHz, and

2.8 meters long at 50 MHz. Unfortunately, this is too

unwieldy for many anechoic chambers and test sites. The

optional end plates of the Model 3142B make it look like

an antenna twice as long as its 1.4 meter length. The result

is about a 10 dB improvement in low-frequency transmit

gain and receive antenna factor compared to a same-length

regular bow-tie.

With the end plates attached to the Model 3142B bow-tie

elements the equivalent dipole electrical length is

increased, thereby decreasing resonant frequency and

increasing efficiency in the 20-60 MHz range. Similarly,

the regular bow-tie has a lower resonant frequency than an

REV C – PN 399229

Archived 09/23/10