Introduction – Bird Technologies 8251D208 User Manual

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Chapter 1

Introduction

This publication covers the Termaline Coaxial Load Resistor

Model 8251D208. The Termaline Coaxial Load Resistor will

generally be referred to as a load thoughout this manual.

This chapter contains introductory information including

product specifications; items supplied; and accessory items

available.

Purpose and

Function

The Bird Termaline Coaxial Load Resistor is a portable,

general purpose 50 ohm coaxial transmission line termina-

tion. The load is a low reflection, nonradiating termination

for coaxial transmission lines operating in the UHF (470 -

860 MHz) band.

The load is rectangular in shape with transverse fins encas-

ing a dielectric coolant cylinder. A retractable handle is re-

cessed in the radiator fins. The front and rear fins are made

of heavier gauge material and are bent 90° to form bottom

mounting flanges. These flanges are supports for free stand-

ing use, or brackets for fixed mounting. Holes are provided

in the flanges for fixed mounting.

Applications

Use these loads:

As a substitute antenna for tuning transmit-

ters under nonradiation conditions or making

routine test and adjustments.

As a substitute for any circuit loading ele-

ment.

To measure, with a suitable indication device,

the power output of any coaxially transmitted

signal within their range.

Performance

Characteristics

and

Capabilities

The Model 8251D208 load can absorb up to 1000 watts con-

tinuously and dissipate it harmlessly as heat over a fre-

quency range of 470 to 860 MHz. The actual VSWR, “voltage

standing wave ratio”, will not exceed 1.065:1 over the fre-

quency range stated.

Power and

Utility

Requirements

This load is a passive device that is self-contained and re-

quires only RF input to function.