Introduction – Bird Technologies 8201 User Manual

Page 11

Chapter 1

Introduction

This publication refers to the Termaline Load Resistors

Models 8201 and 8203. The differences between the models

are listed in the specifications. Both models will generally

be referred to as a load throughout this manual.

Purpose and

Function

These loads are portable, general purpose 50 ohm coaxial

transmission line terminations. They are self-contained

units requiring no outside power source or additional equip-

ment. The Model 8201 load provides an accurate, depend-

able, and practically nonreflective termination for testing

and adjusting transmitters under nonradiating conditions

from dc to 2500 MHz and the Model 8203 from dc to 1000

MHz.

Some examples of the uses of these loads are:

As a substitute antenna.

For tuning RF transmitters - under

nonradiating conditions.

For making routine tests and adjustments.

As a substitute for any 50 ohm circuit loading

element.

To measure, with a suitable indicating device,

the power output of any coaxially transmitted

RF signal within its rating.

Description

These models are rectangular in shape with transverse fins

encasing an oil-dielectric-filled coolant cylinder. A retract-

able handle is recessed in the radiator fins. Extra thick fins

at the front and rear are bent 90° to form bottom mounting

flanges. These flanges are supports for free standing use or

brackets for fixed mounting. Flange holes are provided for

this purpose.

Performance

and

Capabilities

The Model 8201 Termaline Load Resistor can absorb and

dissipate up to 500 W of RF power continuously over a fre-

quency range of dc to 2500 MHz. It will show a maximum

VSWR of 1.1 to 1.0 from dc to 1000 MHz and 1.25 to 1.0

from 1000 to 2500 MHz.

The Model 8203 Termaline Load Resistor will take a load of

up to 600 W, over a frequency range of dc to 1000 MHz. Its