Linear AT7400 User manual

AT7400 Owner Manual Rev. 2.0 – October 2006-10-23 1/1 1
ADVANCED TV
LINE
Model AT7400
400W ATSC UHF Transmitter
OWNERS MANUAL
Linear Industries Incorporation
www.linear-tv.com
Made in USA

AT7400 Owner Manual Rev. 2.0 – October 2006-10-23 1/1 1
AT7400
400W ATSC DTV TRANSMITTER
ADVANCED TV LINE
Owner Manual
Table of Contents
Section 1: Technical Specifications
Typical Final Test Report
Section 2: Master Control Unit
Section 3: Exciter Drawer
Section 4: Intermediate Directional Coupler
Section 5: 220W UHF Power Amplifier
Section 6: Output Directional Coupler, and Filtering
Section 7: Energy Distribution and Control
Annex A: Schematics Diagrams

AT7400 Owner Manual Rev. 2.0 – October 2006-10-23 1/3
User Notices and WARNINGS
USER NOTICES
IT IS VERY IMPORTANT TO READ THE FOLLOWING MANUAL SECTIONS PRIOR TO
OPERATION OF THIS TRANSMITTER!
Notice 1
The transmitter main operating voltage setting is marked on the rear of the AT7250 chassis.
Notice 2
The transmitter operating frequency is set from the factory.
Notice 3
For adjusting the RF output power setting a qualified technician should always employ the use of an
RF Wattmeter and a calibrated dummy load.
Notice 4
Should accident or injury occur to the personnel engaged in the installation, operation, or service of
the equipment should seek proper medical attention. It is advisable that such personnel have
familiarity with first-aid practices.
Notice 5
To call our technical support center or for other customer service issues at Linear Inc, refer to the
following number: 630 346 6698.
Notice 6
If you experience some specific difficulty and the technical information available in this manual is
not enough to help you, do not hesitate to call LINEAR technical support center.
Notice 7
The technical information presented on this manual is sole intellectual propriety of LINEAR
INDUSTRIES Inc. Reproduction of this document in full or partial is prohibiting with out written
authorization. This document is legally protected by the copy rights laws.

AT7400 Owner Manual Rev. 2.0 – October 2006-10-23 2/3
WARNING!
THE VOLTAGES AND CURRENTS IN THIS EQUIPMENT ARE DANGEROUS. PERSONEL
MUST, AT ALL TIMES, OBSERVE SAFETY WARNINGS, INSTRUCTIONS, AND ANY
REGULATIONS.
THIS OWNER’S MANUAL IS INTENDED AS A GENERAL GUIDE FOR TRAINED AND
QUALIFIED PERSONNEL WHO ARE AWARE OF THE DANGERS THAT ARE INHERENT IN THE
HANDLING AND OPERATION OF POTENTIALLY HAZARDOUS ELECTRICAL AND
ELECTRONIC CIRCUITS. IT IS NOT THE INTENT OF THIS MANUAL TO PROVIDE A
COMPLETE SET OF SAFETY INSTRUCTIONS OR PRECAUTIONS THAT SHOULD ALREADY
BE UNDERSTOOD BY TRAINED OR EXPERIENCED PERSONNEL IN USING THIS OR OTHER
TYPES OF ELECTRONIC EQUIPMENT.
THE INSTALLATION, OPERATION, AND MAINTENANCE OF THIS EQUIPMENT INVOLVE
RISKS TO PERSONNEL AND ALSO TO THE EQUIPMENT. LINEAR, INC. SHALL NOT BE
RESPONSIBLE FOR INJURY OR DAMAGE THAT IS THE RESULT OF IMPROPER
PROCEDURES OR USE BY PERSONS IMPROPERLY TRAINED OR LACKING THE
KNOWLEDGE TO PERFORM ASSOCIATED TASKS.
ALL LOCAL CODES FOR BUILDING, SAFETY, FIRE, OR RELATED STANDARDS MUST BE
OBSERVED. CONSULT LOCAL AUTHORITIES FOR THE STANDARDS FOR THE AREA OR
REGION WHERE THE EQUIPMENT WILL BE INSTALLED AND PUT IN USE.
WARNING!
AT ALL TIMES DISCONECT AC/MAINS POWER BEFORE OPENING COVERS, DOORS,
ENCLOSURES, PANELS, OR PROTECTIVE SHIELDS THAT EXPOSE LIVE CIRCUITS. NEVER
PERFORM MAINTENANCE, MAKE ADJUSTMENTS, OR SERVICE THE EQUIPMENT WHEN
ALONE OR FATIGUED.
WARNING!
IF ELECTROLYTIC OR OIL FILLED CAPACITORS ARE UTILIZED IN THE EQUIPMENT AND
THE COMPONENT APPEARS LEAKY, OR IS BULGING, OR IF THE CASE OR COVERING OF
THE COMPONENT APPEARS DAMAGED OR DISTRESSED ALLOW SUFFICIENT TIME FOR
THE UNIT TO COOL OR FULLY DISCHARGE BEFORE SERVICING. SERVICING HOT OR
LEAKY CAPACITORS CAN CAUSE A RUPTURE OF THE CASE AND POSSIBLE INJURY.

AT7400 Owner Manual Rev. 2.0 – October 2006-10-23 3/3
Returns and Exchanges
Equipment (Damaged or undamaged) should not be returned unless written approval and a
Merchandise Return Authorization (MRA Number) is received from your Linear Sales representative
or Linear Customer Service. Special shipping instruction will be provided which will assure proper
handling. The circumstances and reasons for the return must be included in the request for return.
Equipment that is special or “custom” ordered may be not returnable. In situations where return or
exchange is at the request of the customer a restocking fee may be charged. All returns must be
sent freight prepaid and properly insured by customer. When communicating with Linear please
refer to your Order or Invoice Number.
Unpacking
Use care when unpacking the equipment. First perform a visual inspection of the item(s) to
determine if any damage occurred during shipment. Be sure to retain all the shipping materials
(crates and boxes or cartons) until such time that it has been determined that the received
equipment arrived undamaged. Find all PACKING LISTS and keep them to assist in locating and
identifying any components or assemblies that may have been removed for shipping and might
need to be reinstalled in the equipment. Make sure that all shipping straps, supports and packing
materials are completely removed from the equipment prior to initialization and use.

AT7400 Owner Manual Rev. 2.0 – October 2006-10-23 Section 1 - 1/7 1
Section 1 – AT7400 Technical Specifications
1. Introduction
The AT7400 is a 400W UHF ATSC/8VSB transmitter assembled and tested in United States by LINEAR
INDUSTRIES INC. (www.linear-tv.com).
Fig1.1: AT7400 Front View, cabinet wheels are optional.

AT7400 Owner Manual Rev. 2.0 – October 2006-10-23 Section 1 - 2/7 2
2. AT7400 RF line Up
3. AT7400 Cabinet Air Flux: 0.25m3/sec. - 21ft3/sec.
Fig. 1.4: Air flux path at AT4700 cabinet, (lateral view). Darker area denotes the internal heat source, or the RF drawers,
(1) Exciter and (2) PA’s.
Cold Air Inlet
Air Outlet

AT7400 Owner Manual Rev. 2.0 – October 2006-10-23 Section 1 - 3/7 3
4. AT7400 – 400W UHF ATSC/8VSB Transmitter - Technical Specifications
Electrical
Main 220/240 VAC, bi phase, 50-60 Hz. 3w.
Consumption 3200W.
PFC Included
Signal Input
Transport Stream Input ATSC/MPEG2, compliant to SMPTE310M
Input Data Rate 19.39 Mbps
External Reference Signal 10MHz. (0 to +10 dBm).
Input Connector 75ȍ(BNC),
Reference Input Connector 50ȍ(BNC),
RF
RF Output Power 400w (rms)
Modulation Mode 8VSB. All-Digital Complex IF modulation
IF 18.833916 MHz.
Channel Bandwidth 6MHz.
Test Signal PRBS. Pseudo Random Bit Sequence
Frequency Range UHF. Ch14 to Ch69, (4 bands).
Frequency Step 1 Hz. ± 220kHz
Symbol Rate 10.76 MSymbol/sec.
Digital/Analog Converter 16 bit
All –Digital Linear. Pre-Correction Included
Pilot frequency stability overall ± 0.3 ppm.
Peak to peak frequency response 0.15 dB.
Peak to peak group delay response 15 ns.
Phase noise -104 dBc/Hz @ 20kHz offset.
Conducted spurious and harmonics < -60 dBc, FCC 47 Part 74.
Radiated spourious and harmonics < -80 dBc, FCC 47 Part 74.
39dB (modulator output) typical.
39 dB (exciter output) typical.
MER (Modulation Error Rate)
29 dB (transmitter output) typical.
RF output connector EIA 7/8” Flanged.
Output sample connector N
Remote Control
RS-232 Dial-up network interface via hyper-terminal
Ethernet SNMP. IP network interface via Web Browser.
Mechanical
Internal drawer’s air speed: 400 ft/minute.
Air Refrigeration Overall Air flow: 21ft3/sec.
Dimensions 58”(H), 28”(W), 43”(D)
Weight Gross: 286.7 Kg NET: 236.70 Kg
Foot print 28”(W), 7’(D)

AT7400 Owner Manual Rev. 2.0 – October 2006-10-23 Section 1 - 4/7 4
5. AT4700 Available Models and Options
Models
AMono-phase; 220Vac.
B3-phase; 220Vac – 380Vac; 3 wires.
C3-phase; 220Vac – 380Vac; 4 wires.
Options:
01 Integrated GPS receiver
02 Adaptive digital pre-correction
03 Dual Exciter
04 Analog Transmission Mode
05 Cabinet 4 wheels
6. AT7400 Typical Test Report
6.1.Out of Channel Emissions

AT7400 Owner Manual Rev. 2.0 – October 2006-10-23 Section 1 - 5/7 5
6.2.Frequency Response and Group Delay
6.3.Carrier Phase Noise