Northern Airborne Technology 246 User Manual

Installation and Operation Manual

Model 246

Isolation Amplifier

SM246

ISSUE 2.00

Northern Airborne Technology Ltd.

1925 Kirschner Road

Kelowna, BC, Canada.

V1Y 4N7

Telephone [phone]

Facsimile [phone]

Issued on the authority of Northern Airborne Technology Ltd.

Copyright 1996

Model 246 Isolation Amplifier

SM246 Installation and Operation Manual

Northern Airborne Technology Ltd.

has acquired the assets of dB Systems Inc.,
and has revised and reissued this manual in

standard NAT format.

Northern Airborne Technology Ltd.

will be responsible for all future

amendments and revisions.

Installation and Operation Manual Page ii

ENG-FORM: 820-0114.DOT

CONFIDENTIAL AND PROPRIETARY TO NORTHERN AIR BORNE TECHNOLOGY LTD.

Model 246 Isolation Amplifier

SM246 Installation and Operation Manual

Table of Contents

Section Title Page

1. Description

1.1 Introduction 1-1

1.2 Product Description 1-1

1.3 Design Features 1-1

1.4 Specifications 1-1

1.4.1 Electrical Specifications 1-1

1.4.2 Physical Specifications 1-1

1.4.3 Environmental Specifications 1-2

1.4.3 Product Approval 1-2

2. Installation

2.1 Introduction 2-1

2.2 Unpacking and Inspection 2-1

2.2.1 Warranty 2-1

2.3 Continued Airworthiness 2-1

2.4 Installation Procedures 2-1

2.4.1 Warnings 2-1

2.4.2 Cautions 2-2

2.4.3 Cabling and Wiring 2-2

2.4.4 Pin Identification 2-2

2.4.5 Beech/King Air Interphone Interconnect 2-3

2.4.6 Typical Collins Interconnect 2-4

2.4.7 Post Installation Checks 2-5

2.5 Adjustments and Connections 2-5

2.5.1 Mechanical Installation 2-5

2.5.2 Adjustments 2-5

2.6 Accessories Required But Not Supplied 2-6

2.7 Installation Drawings 2-6

3. Operation

3.1 Introduction 3-1

3.2 General Information 3-1

Installation and Operation Manual Page iv

ENG-FORM: 820-0114.DOT

CONFIDENTIAL AND PROPRIETARY TO NORTHERN AIR BORNE TECHNOLOGY LTD.

Model 246 Isolation Amplifier

SM246 Installation and Operation Manual

Section 1 Description

1.1 Introduction

Information in this section consists of product description, design features and specifications for the
Model 246 Isolation Amplifier. All derivative product information shall be contained in the applicable
manual supplement, which may be obtained from NAT as required.

Review all notes, warnings and cautions.

1.2 Product Description

The Model 246 Isolation Amplifier is an electronic device capable of driving 100 mWrms into a
600 Ohm load. It is intended as a direct replacement for the Collins model 356C-4. The Model 246 is
also capable of driving 5 Wrms into an 8 Ohm load.

1.3 Design Features

The Model 246 Isolation Amplifier is based on a solid-state integrated circuit. It has a 470 Ohm
differential input and an output compatible with a 600 Ohm or a 4 Ohm load. It provides an internal gain
adjustment (accessible through a hole in the cover) of 4.5 dB to 42 dB and is capable of supplying a
minimum of 100 mW into a 600 Ohm load. It will drive headphones with impedance ratings of 4 to 600
ohms. With the unit adjusted for a gain of 40 dB, an input level of 77.5 mVrms will produce an output
level of 7.75 Vrms (100 mW into 600 ohms.)

1.4 Specifications

1.4.1 Electrical Specifications

Input 0.0775 Vrms into 470 ohms
Output 100 mWrms into 600 ohms at <1 % distortion

Microphone Bias

15 Vdc at 30 ±5 mA (enabled by internal jumper)

Output Noise 70 dB below 100 mW
Power Supply <0.5 amp at 28 Vdc, 1 A circuit breaker recommended

1.4.2 Physical Specifications

Height 1.53" (38.86 mm) max
Depth 2.81" (71.37 mm) max including flanges
Width 2.78" (70.61 mm) max excluding connector
Weight 0.35 lbs (159 g)

Section 1 Rev: 1.00 Issue 2 Page 1-1

ENG-FORM: 800-0113.DOT

CONFIDENTIAL AND PROPRIETARY TO NORTHERN AIR BORNE TECHNOLOGY LTD.

Model 246 Isolation Amplifier

SM246 Installation and Operation Manual

1.4.3 Environmental Specifications

Temperature -55°C to +70°C
Altitude 70,000 ft

Qualification of the Model 246 Isolation Amplifier was completed in accordance with
RTCA/DO-160C Environmental Categories: [A2F2]-BA[CL]XXXXXXZ[BZ]AAATZ[XXC2]XX

Note: Refer to Environmental Qualification Form located in Section 2 of this Manual for complete details

of the environmental categories.

1.4.4 Product Approval

FAA: TSO-C50c (RTCA/DO-214, RTCA/DO-160C)

Section 1 ends

Section 1 Rev: 1.00 Issue 2 Page 1-2

ENG-FORM: 800-0113.DOT

CONFIDENTIAL AND PROPRIETARY TO NORTHERN AIR BORNE TECHNOLOGY LTD.