UBS Axcera 430B User Manual
INSTRUCTION MANUAL
430B
1-kW VHF High Band
Transmitter
AXCERA, LLC
103 FREEDOM DRIVE P.O. BOX 525 LAWRENCE, PA 15055-0525 USA
(724) 873-8100 • FAX (724) 873-8105
www.axcera.com • info@axcera.com
1000 Watt VHF High Band Transmitter Table of Contents
TABLE OF CONTENTS
CHAPTER 1 INTRODUCTION
1.1 Manual Overview ............................................................................ 1-1
1.2 Assembly Designation Procedure ....................................................... 1-1
1.3 Safety.......................................................................................... 1-1
1.4 Maintenance.................................................................................. 1-2
1.5 Material Return Procedure ................................................................ 1-2
1.6 Limited One-Year Warranty for Axcera Products................................... 1-3
CHAPTER 2 SYSTEM DESCRIPTION AND REMOTE INTERFACE CONNECTIONS
2.1 System Overview ........................................................................... 2-1
2.2 Control and Status.......................................................................... 2-2
2.2.1 VHF Exciter Tray .................................................................... 2-3
2.2.2 VHF High Band Amplifier Tray ................................................... 2-5
2.3 Input Connections .......................................................................... 2-6
2.4 AC Input to the transmitter.............................................................. 2-6
2.5 Remote Interface Connections .......................................................... 2-6
CHAPTER 3 INSTALLATION AND SETUP PROCEDURES
3.1 Site Considerations ......................................................................... 3-1
3.2 Unpacking the Cabinets and Trays..................................................... 3-4
3.3 Installing the Cabinets and Trays....................................................... 3-5
3.4 Setup and Operation ....................................................................... 3-6
CHAPTER 4 CIRCUIT DESCRIPTIONS
4.1 VHF Hi gh Band Exciter..........................................................................4-1
4.1.1 Aural IF Synthesizer Board, 4.5 MHz ...............................................4-1
4.1.2 Sync Tip Clamp/Modulator Board ....................................................4-2
4.1.3 Delay Equalizer Board ..................................................................4-6
4.1.4 IF Carrier Oven Oscillator Board .....................................................4-6
4.1.5 ALC Board, NTSC.........................................................................4-7
4.1.6 IF Phase Corrector Board ............................................................ 4-13
4.1.7 VHF Mixer/Amplifier Enclosure Assembly ........................................ 4-15
4.1.8 Transmitter Control Board ........................................................... 4-17
4.1.9 Visual/Aural Metering Board ......................................................... 4-22
4.1.10 Channel Oscillator Assembly, Dual Oven....................................... 4-23
4.1.11 (Optional) EEPROM FSK Identifier Board ....................................... 4-23
4.1.12 (Optional) IF Attenuator Board ................................................... 4-24
4.2 VHF High Band Amplifier Trays ............................................................. 4-24
CHAPTER 5 DETAILED ALIGNMENT PROCEDURES
5.1 VHF High Band Exciter Tray with Baseband Video and Audio Inputs........... 5-1
5.2 VHF Exciter Tray with 4.5-MHz Composite Input Kit ............................... 5-1
5.3 VHF Exciter Tray with Either Baseband or 4.5-MHz Composite Input.......... 5-2
5.4 IF Phase Corrector Adjustment .......................................................... 5-3
5.5 Linearity Corrector Adjustment .......................................................... 5-3
5.6 Phase and Gain Adjustment of the VHF Amplifier Trays ........................... 5-4
430B, Rev. 0 i
1000 Watt VHF High Band Transmitter Table of Contents
TABLE OF CONTENTS (continued)
5.7 Calibration of the Forward Output Power Level of the Transmitter............. 5-5
5.8 Calibration of the Reflected Output Level of the Transmitter..................... 5-5
5.9 2-Way Combiner Assembly ............................................................... 5-6
5.10 Bandpass Filter Assemblies .............................................................. 5-6
5.11 VHF High Band Amplifier Tray .......................................................... 5-6
5.11.1 AGC Control Board ................................................................ 5-6
5.11.2 Phase Shifter Board ............................................................... 5-7
5.11.3 VHF Filter/Amplifier Board ...................................................... 5-7
5.11.4 VHF High Band Amplifier Board................................................ 5-7
5.11.5 Overdrive Protection Board ..................................................... 5-7
5.11.6 VHF High Band Amplifier Board................................................ 5-7
5.11.7 3-Way Splitter Board ............................................................. 5-8
5.11.8 VHF High Band Amplifier Board................................................ 5-8
5.11.9 3-Way Combiner Board .......................................................... 5-8
5.11.10 Calibration of the Visual Plus Aural Output
Power and VSWR Cutback..................................................... 5-8
5.12 Board Level Alignment Procedures .................................................... 5-9
5.12.1 (Optional) 4.5-MHz Composite Input Kit .................................... 5-9
5.12.2 Delay Equalizer Board ...........................................................5-10
5.12.3 (Optional) Composite 4.5-MHz Filter Board ...............................5-10
5.12.4 (Optional) 4.5-MHz Bandpass Filter Board.................................5-10
5.12.5 IF Carrier Oven Oscillator Board..............................................5-11
5.12.6 Sync Tip Clamp/Modulator Board ............................................5-11
5.12.7 Aural IF Synthesizer Board, 4.5 MHz ........................................5-13
5.12.8 ALC Board (Part 1 of 2) .........................................................5-14
5.12.9 IF Phase Corrector Board .......................................................5-15
5.12.10 ALC Board, NTSC (Part 2 of 2)..............................................5-15
5.12.11 Channel Oscillator Board, Dual Oven ......................................5-16
5.12.12 x4 Multiplier Board .............................................................5-16
5.12.13 VHF Filter/Mixer Board ........................................................5-16
5.12.14 VHF High Band Filter/Amplifier Board .....................................5-17
APPENDICES
APPENDIX A SYSTEM SPECIFICATIONS
APPENDIX B SAMPLE LOG REPORT SHEET & TYPICAL OPERATIONAL READINGS
APPENDIX C ASSEMBLY DRAWINGS
APPENDIX D SUBASSEMBLY DRAWINGS
430B, Rev. 0 ii
1000 Watt VHF High Band Transmitter Table of Contents
LIST OF FIGURES
4-1 1 kW Minimum Ventilation Configuration ....................................... 4-4
4-2 Chassis Trak Cabinet Slides ........................................................ 4-5
5-1 Waveform..............................................................................5-12
430B, Rev. 0 iii
1000 Watt VHF High Band Transmitter Table of Contents
LIST OF TABLES
2-1 430B Major Trays and Assemblies................................................ 2-1
2-2 VHF Exciter Tray Meters ............................................................. 2-3
2-3 VHF Exciter Tray Switches.......................................................... 2-4
2-4 VHF Exciter Tray Fault Indicators ................................................. 2-4
2-5 VHF Exciter Tray Samples .......................................................... 2-5
2-6 VHF Amplifier Tray Switches....................................................... 2-6
2-7 VHF Amplifier Tray Fault Indicators .............................................. 2-7
2-8 VHF Amplifier Tray Control Adjustments........................................ 2-7
2-9 VHF Amplifier Tray Sample ......................................................... 2-7
2-10 VHF Exciter Remote Interface Connections
With the A/V Input and Remote Interface Assembly .................... 2-8
2-11 VHF Amplifier Tray Remote Interface Connections
With the A/V Input and Remote Interface Assembly ...................2-10
3-1 VHF Amplifier Tray Boards and Assemblies ...................................3-25
5-1 Bandpass Filter Typical Values..................................................... 5-6
5-2 ALC Board LEDs ......................................................................5-14
430B, Rev. 0 iv
1000 Watt VHF High Band Transmitter Chapter 1, Introduction
Chapter 1
Introduction
1.1 Manual Overview
This manual explains the installation,
setup, alignment, and maintenance
procedures for the 430B 1000 Watt solid
state VHF high band transmitter. It is
important that you read all of the
instructions, especially the safety
information in this chapter, before you
begin to install or operate the unit.
This instruction manual is divided into
five chapters and supporting appendices.
Chapter 1, Introduction, contains
information on the assembly numbering
system used in the manual, safety,
maintenance, return procedures, and
warranties. Chapter 2, System
Description, Maintenance and Remote
Interface Connections, describes the
transmitter and includes discussions on
system control and status indicators,
maintenance, and remote control
connections. Chapter 3, Installation and
Setup Procedures, describes how to
unpack, install, setup, and operate the
transmitter. Chapter 4, Circuit
Descriptions, contains a detailed
discussion of the circuits and boards that
make up the 430B transmitter. Chapter
5, Detailed Alignment Procedures,
provides information on adjusting the
system to achieve peak operation of the
assemblies. The appendices contain
system specifications, a sample log
sheet, schematic, interconnects,
assembly and subassembly drawings and
parts list.
1.2 Assembly Designation Procedure
Axcera has assigned assembly numbers,
such as Ax (x=1,2,3…), to all assemblies,
trays, and boards that are referenced in
the text of this manual and shown on the
block diagrams and interconnect
drawings provided in the appendices.
These supporting documents are
arranged in increasing numerical order in
the appendices. Section titles in the text
for assembly or tray descriptions or
alignment procedures also indicate the
associated drawing(s) and the relevant
appendix that contains the drawing.
Sections describing vendor-supplied
items, such as meters and power
supplies, do not contain this information.
1.3 Safety
The VHF transmitters manufactured by
Axcera are designed to be easy to use
and repair while providing protection
from electrical and mechanical hazards.
Listed throughout the manual are notes,
cautions, and warnings concerning
possible safety hazards that may be
encountered while operating or servicing
the transmitter. Please review these
warnings and familiarize yourself with the
operation and servicing procedures
before working on the transmitter.
Read All Instructions – All of the
operating and safety instructions should
be read and understood before operating
this equipment .
Retain Manuals – The manuals for the
transmitter should be retained at the
transmitter site for future reference. We
provide two sets of manuals for this
purpose; one set can be left at the office
while one set can be kept at the site.
Heed all Notes, Warnings, and
Cautions – All of the notes, warnings,
and cautions listed in this safety section
and throughout the manual must be
followed.
Follow Instructions – All of the
operating and use instructions for the
transmitter should be followed.
Cleaning – Unplug or otherwise
disconnect all power from the equipment
before cleaning. Do not use liquid or
430B, Rev. 0 1-1
1000 Watt VHF High Band Transmitter Chapter 1, Introduction
aerosol cleaners. Use a damp cloth for
cleaning.
Ventilation – Openings in the cabinets
and tray front panels are provided for
ventilation. To ensure reliable operation
of the transmitter, and to protect the unit
from overheating, these openings must
not be blocked.
Servicing – Do not attempt to service
this product yourself until becoming
familiar with the equipment. If in doubt,
refer all servicing questio ns to qualified
Axcera service personnel.
Replacement Parts – When
replacement parts are used, be sure that
the parts have the same functional and
performance characteristics as the
original part. Unauthorized substitutions
may result in fire, electric shock, or other
hazards. Please contact the Axcera
Technical Service Department if you have
any questions regarding service or
replacement parts.
1.4 Contact Information
The Axcera Field Service Department can
be contacted by phone at (724) 873-
8100 or by fax at (724) 873-8105.
Before calling Axcera, please be prepared
to supply the Axcera technician with
answers to the following questions. This
will save time and help ensure the most
direct resolution to the problem.
1. What are the Customers’ Name and
c all letters?
2. What are the model number and
type of transmitter?
3. How long has the transmitter been
on the air? (Approximately when
was the transmitter installed)
4. What are the symptoms being
exhibited by the transmitter?
Include current front panel meter
readings. If possible, include front
panel meter readings before the
problem occurred.
1.5 Material Return Procedure
To insure the efficient handling of
equipment or components that have been
returned for repair, Axcera requests that
each returned item be accompanied by a
Material Return Authorization Number
(MRA#).
An MRA# can be obtained from any
Axcera Field Service Engineer by
contacting the Axcera Field Service
Department at (724) 873-8100 or by fax
at (724) 873-8105. This procedure
applies to all items sent to the Field
Service Department regardless of
whether the item was originally
manufactured by Axcera.
When equipment is sent to the field on
loan, an MRA# is included with the unit.
The MRA# is intended to be used when
the unit is returned to Axcera. In
addition, all shipping material should be
retained for the return of the unit to
Axcera.
Replacement assemblies are also sent
with an MRA# to allow for the proper
routing of the exchanged hardware.
Failure to close out this type of MRA# will
normally result in the customer being
invoiced for the value of the loaner item
or the exchange assembly.
When shipping an item to Axcera, please
include the MRA# on the packing list and
on the shipping container. The packing
slip should also include contact
information and a brief description of why
the unit is being returned.
Please forward all MRA items to:
Axcera, LLC
103 Freedom Drive
P.O. Box 525
Lawrence, PA 15055-0525 USA
For more information concerning this
procedure, call the Axcera Field Service
Department.
430B, Rev. 0 1-2
1000 Watt VHF High Band Transmitter Chapter 1, Introduction
Axcera can also be contacted through email at info@axcera.com and on the
Web at www.axcera.com.
1.6 Limited One Year Warranty for
Axcera Products
Axcera warrants each new product that
it has manufactured and sold against
defects in material and workmanship
under normal use and service for a
period of one (1) year from the date of
shipment from Axcera's plant, when
operated in accordance with Axcera's
operating instructions. This warranty
shall not apply to tubes, fuses,
batteries, or bulbs.
Warranties are valid only when and if
(a) Axcera receives prompt written
notice of breach within the period of
warranty, (b) the defective product is
properly packed and returned by the
buyer (transportation and insurance
prepaid), and (c) Axcera determines, in
its sole judgment, that the product is
defective and not subject to any misuse,
neglect, improper installation,
negligence, accident, or (unless
authorized in writing by Axcera) repair
or alteration. Axcera's exclusive liability
for any personal and/or property
damage (including direct, consequential,
or incidental) caused by the breach of
any or all warranties, shall be limited to
the following: (a) repairing or replacing
(in Axcera's sole discretion) any
defective parts free of charge (F.O.B.
Axcera’s plant) and/or (b) crediting (in
Axcera's sole discretion) all or a portion
of the purchase price to the buyer.
Equipment furnished by Axcera, but not
bearing its trade name, shall bear no
warranties other than the special hours of-use or other warrant ies extended by
or enforceable against the manufacturer
at the time of delivery to the buyer.
NO WARRANTIES, WHETHER
STATUTORY, EXPRESSED, OR
IMPLIED, AND NO WARRANTIES OF
MERCHANTABILITY, FITNESS FOR
ANY PARTICULAR PURPOSE, OR
FREEDOM FROM INFRINGEMENT,
OR THE LIKE, OTHER THAN AS
SPECIFIED IN PATENT LIABILITY
ARTICLES, AND IN THIS ARTICLE,
SHALL APPLY TO THE EQUIPMENT
FURNISHED HEREUNDER.
430B, Rev. 0 1-3
1000 Watt VHF High Band Transmit ter Chapter 2, System Description,
Maintenance and Remote Interface Connections
Chapter 2
System Description, Maintenance
and Remote Interface Connections
The 430B is a complete 1000 watt VHF
high band solid state internally diplexed
television transmitter that operates at a
nominal visual output power of 1000
watts peak sync and an average aural
output power of 100 watts, at an A/V
Table 2-1. 430B Major Trays and Assemblies
MAJOR ASSEMBLY
DESIGNATOR
A2 AC distribution panel 1265-1600
A4 VHF exciter 1070901
A6 and A7 Two VHF amplifier trays 1301169
A8 VHF combiner assembly 1219-1006
A12 Remote interface assembly 1083510
The (A4) VHF exciter can operate using
either the baseband audio and video
inputs alone or, if the (optional) 4.5-MHz
composite input kit is purchased, the 4.5MHz composite input or the baseband
video and audio inputs to produce a
diplexed, modulated, and on-channel
frequency visual + aural RF output. The
switching is accomplished by a relay on
the sync tip clamp modulator board that
uses a baseband select to control a relay
that selects either the 4.5 MHz generated
from the baseband inputs or from the
4.5-MHz composite input.
To operate the transmitter with the
(optional) 4.5-MHz composite input kit
using baseband inputs, the baseband
video must be connected to J1 or J2, the
baseband audio must be connected to
the proper input jack, and a baseband
select must be connected from J7-6 and
J7-7. To operate the transmitter with the
(optional) 4.5-MHz composite input kit
using the 4.5-MHz composite input, the
4.5-MHz composite input must be
connected to J1 or J2 and the baseband
select must be removed from J7-6 and
J7-7.
TRAY/ASSEMBLY NAME DRAWING NUMBER
ratio of 10 dB, 10% sound, or 50 watts
at 13 dB, 5% sound.
2.1 System Overview
The 430B is made up of the trays and
assemblies listed in Table 2-1.
The RF output of the VHF exciter is split
two ways in (A5) the 2-way power
splitter assembly (ZFSC-2-2SMA). The
outputs of the splitter feed the two (A6
and A7) VHF high band amplifier trays
that amplify the RF signals to
approximately 600 watts pk. of sync
each. The outputs of the two VHF
amplifier trays are combined in (A8) a
VHF combiner assembly that provides
approximately 1050 watts peak of sync
output. The 1050 watt output is
connected to (A9) a bandpass filter
assembly. The bandpass filter is tuned to
provide the high out -of-band rejection of
unwanted products. The filter assembly
provides a forward and a reflected power
sample to the visual/aural metering
board in the VHF exciter. The forward
sample is processed to provide peak
detected visual and aural power output
samples to the transmitter control board
in the VHF exciter. The reflected power
sample is also peak detected and wired
to the transmitter control board. The
transmitter control board connects the
visual, aural, and reflected power output
samples to the front panel meter for
monitoring the system.
430B, Rev. 0 2-1
1000 Watt VHF High Band Transmit ter Chapter 2, System Description,
Maintenance and Remote Interface Connections
In the VHF amplifier tray, a forward
power sample and a reflected power
sample from the 3-way combiner board
are connected to the AGC Control Board
that peak-detects the samples and
connects them to the fro nt panel meter
of the tray.
2.2 Control and Status
Control and status information for the
transmitter is provided by the meter and
LED indicators on the front panel of the
VHF exciter. The switches and LED
indicators are part of the (A17)
transmitter control board that is mounted
so that the switches and LEDs are
operated or viewed from the front panel
of the VHF exciter.
Switch S1 is an Operate/Standby switch
that controls the output of the
transmitter by providing the Enables
that, when the transmitter is in Operate,
are needed to turn on the switching
power supplies in the two VHF amplifier
trays. In Operate, the green LED DS2 is
on and in Standby the amber LED DS1 is
on. NOTE: If the transmitter does not
switch to Operate when S1 is switched to
Operate, check that a dummy jumper
plug, with a jumper between pins 21 and
22, is connected to jack J9 on (A12) the
A/V input and remoter interface
assembly. This jumper provides the
interlock needed for the transmitter to
operate. If the interlock is present , the
green LED DS5, on the transmitter
control board, should be lit.
Switch S2 is an Automatic/Manual switch
that controls the operation of the
transmitter using the presence of the
video input signal. When the switch is in
Automatic, the green LED DS3 is lit and,
if the video input signal to the
transmitter is lost, the transmitter will
automatically switch to Standby. When
the video input signal returns, the
transmitter will automatically switch back
to Operate. With the system in Manual,
the amber LED DS4 is lit and the
operation of the transmitter is controlled
by the front panel switches. During
normal operation of the transmitter,
switch S2 should be in the Auto position.
The front panel of the VHF exciter also
has LEDs that indicate a Video Fault
(Loss; red LED DS9) and VSWR Cutback
(amber LED DS7).
430B, Rev. 0 2-2
1000 Watt VHF High Band Transmit ter Chapter 2, System Description,
Maintenance and Remote Interface Connections
2.2.1 VHF Exciter Tray
Table 2-2. VHF Exciter Tray Meters
METER FUNCTION
This meter reads power in terms of a percentage of the
calibrated output power level on the upper scale. The
voltage level or frequency level is read on one of the bottom
two scales. A full-scale reading on the top scale is 120%.
100% is equivalent to the full-rated 1000 watts peak of
sync visual. The meter also reads % Aural Power, % Exciter
Power, % Reflected Power, audio levels, video levels, and
the ALC reading.
Meter (A4-A18)
With Switch S3 in
Position
Switch S3, Meter
Audio
(0 to 100 kHz)
ALC
(0 to 10 volts)
% Exciter
(0 to 120)
% Aural Power
(0 to 120)
% Visual Power
(0 to 120)
% Reflected
(0 to 120)
Video
(0 to 1 volt)
Selects the desired ALC voltage
reading, % Exciter Power,
% Reflected Power, % Visual
Power, % Aural Power, video
level, or audio level.
Reads the audio level, ±25 kHz
balanced or ±75 kH composite,
on the 0 to 10 scale. Will
indicate baseband audio, if it is
connected to the transmitter,
even with the video + 4.5-MHz
SCA input selected.
Reads the ALC voltage level, .8
VDC, on the 0 to 10 scale.
Reads the % Exciter Output
Power Level needed to attain
100% output of the transmitter
on the top scale.
Reads the % Aural Output
Power of the transmitter,
100% = 100 watts at 10 dB
A/V ratio, on the top scale.
Reads the % Visual Output
Power of the transmitter,
100% = 1000 watts peak of
sync, on the top scale.
Reads the % Reflected Output
Power, <5%, on the top scale.
Reads the video level, at white,
on the bottom 0 to 10 scale.
Display
430B, Rev. 0 2-3
1000 Watt VHF High Band Transmit ter Chapter 2, System Description,
Maintenance and Remote Interface Connections
Table 2-3. VHF Exciter Tray Switches
SWITCH FUNCTION
The momentary switch S1 applies a ground to K1, a latching
relay on the transmitter control board. K1 will switch either
Transmitter S1
Operate/Standby
Mode Select S2
Auto/Manual
Power Adjust (R1)
Table 2-4. VHF Exciter Tray Fault Indicators
INDICATOR DESCRIPTION
Video Loss (DS9 Red)
VSWR Cutback (DS7
Amber)
Table 2-5. VHF Exciter Tray Front Panel Samples
SAMPLE DESCRIPTION
f(IF)
f(IC)
f(s)
Exciter O/P
Transmitter O/P
to Operate or to Standby depending on which direction S1 is
pushed. When switched to Operate, the low, Enable
commands are applied to the two VHF amplifier trays. These
Enables will turn on the VHF amplifier trays. The opposite
occurs when the switch is turned to Standby.
The momentary switch S2 applies a ground to K2, a latching
relay on the transmitter control board. K2 will switch the
transmitter to Automatic or Manual depending on which
direction S2 is pushed. In Automatic, the video fault
command from the ALC Board will control the operation of
the transmitter. The transmitter will switch to Standby, after
a slight delay, if the input video is lost and will switch back
to Operate, quickly, when the video is restored. In Manual,
the transmitter is controlled by the operator using the front
panel Operate/Standby switch or by remote control.
The 5 kΩ pot A20 sets the ALC level on the ALC board to set
the output power of the transmitter.
Indicates that the input video to the transmitter has been
lost. The fault is generated on the ALC board in the VHF
exciter tray.
Indicates that the reflected power level of the transmitter
has increased above 20%; this automatically cuts back the
output power level to 20%. The fault is generated on the
transmitter control board in the VHF exciter tra y.
A sample of the visual IF, 45.75MHz, that is taken from the
sample jack on the IF carrier oven oscillator board.
A sample of the intercarrier signal. 4.5MHz, that is taken
from the sample jack on the aural IF synthesizer board.
A sample of the channel oscillator output that is taken from
the sample jack of the channel oscillator assembly.
An output power sample of the exciter that is taken from
the VHF filter/amplifier board.
A forward power sample of the transmitter that is taken
from the visual/aural metering board.
430B, Rev. 0 2-4
1000 Watt VHF High Band Transmit ter Chapter 2, System Description,
Maintenance and Remote Interface Connections
2.2.2 VHF High Band Amplifier Tray
Table 2-6. VHF High Band Amplifier Tray Switches
SWITCH FUNCTION
Switches 220 VAC through a 15 amp circuit breaker
On/Off Circuit Breaker CB1
Switch S1, Meter
Switch S2, Meter
protection device. The switch lights if AC is present. The AC
is applied to the switching power supply in the tray.
Selects the desired % Visual Forward Output Power, %
Visual Reflected Power reading, AGC Voltage, Power Supply
Voltage, or Current
With Switch S1 in
Position
Reads the % Forward Output
% Forward
% Refl (Reflected)
AGC Voltage
Power Supply
Current
Selects the current of the transistor devices on the high
band amplifier boards. S1 must be in the Current position.
With Switch S2 in
Position
I1
I2
I3
I4
Power of the tray (100%= 600
watts peak of sync + aural)
Reads the % Reflected Output
Power (<10%)
Reads the AGC level of the tray
(1 to 2 VDC)
Reads the voltage from the
switching power supply
(+28 VDC)
Uses Switch S2 to indicate the
current of transistor devices
Reads the current of (A4-A1)
the high band amplifier board
(idling current=6 amps and
operating current=12 amps)
Reads the current of (A4-A2)
the high band amplifier board
(idling current=6 amps and
operating current=12 amps)
Reads the current of (A4-A3)
the high band amplifier board
(idling current=6 amps and
operating current=12 amps)
Reads the current of (A3-A2)
the high band driver board
(idling current=3 amps and
operating current=6 amps)
Display
Display
430B, Rev. 0 2-5
1000 Watt VHF High Band Transmit ter Chapter 2, System Description,
Maintenance and Remote Interface Connections
Table 2-7. VHF High Band Amplifier Tray Fault Indicators
INDICATOR DESCRIPTION
Indicates that the level of drive is too high.
The protection circuit will limit the drive
Overdrive (DS1)
Enable (DS2)
Module Status (DS3)
VSWR Cutback (DS4)
Overtemp (DS5)
Table 2-8. VHF High Band Amplifier Tray Control Adjustments
ADJUSTMENT DESCRIPTION
Phase (A7-R2)
Gain (A6-R3)
Table 2-9. VHF High Band Amplifier Tray Sample
SAMPLE DESCRIPTION
RF Front Panel Sample
2.3 Input Connections
The baseband video and audio inputs
alone or, if the (optional) 4.5-MHz
composite input kit is purchased, the 4.5MHz composite input or the baseband
video input and audio input to the
transmitter, connect to the A/V Input &
Remote Interface Assembly, mounted
facing the rear, at the top of the cabinet.
The baseband video input or the 4.5-MHz
composite input connects to jack J2. The
baseband balanced audio input connects
to TB1 or the composite, stereo, audio to
jack J3. To use the 4.5-MHz composite
level to the set threshold. The fault is
generated on the overdrive protection
board.
Indicates that the Enable supplied by the
exciter tray is present
Indicates that the forward power sample
level is lower than the set reference level
Indicates that the reflected level of the tray
has increased above 20%; this will
automatically cut back the output power of
the tray. The fault is generated on the AGC
control board.
Indicates that the temperature of the
(A4-A5, A4-A6 or A5-A2) thermal switch is
above 175° F. When this fault occurs, the
Enable to the switching power supply is
immediately removed.
Adjusts the phase of the RF output by
approximately 70°
Adjusts the gain of the RF output when the
amplifier control board is in the AGC mode
Forward power sample of the tray from the
AGC control board
input kit, the baseband audio can remain
connected even if the 4.5-MHz composite
input kit is used, but the baseband video
must be disconnected from J2 and the
4.5-MHz composite input must be
connected to J2. The baseband select
command must be removed from J7-6
and J7-7.
2.4 AC Input to the Transmitter
The transmitter needs an AC input of 220
VAC at 40 amps connected to it in order
to operate. The 220 VAC input connects
to (A2) the AC distribution panel in the
430B, Rev. 0 2-6
1000 Watt VHF High Band Transmit ter Chapter 2, System Description,
Maintenance and Remote Interface Connections
upper middle facing the rear of the
cabinet. The panel contains the terminal
block TB1 to which the 220 VAC input
connects.
The AC distribution panel contains four
circuit breakers that supply the AC to the
rest of the transmitter. The input AC is
connected to the main AC circuit breaker
CB1 (40 amps) that distributes the 220
VAC to the terminal block TB2. TB2 has
three MOVs, VR1, VR2, and VR3,
mounted to the terminal block: VR1
across Line 1, VR3 across Line 2 and VR2
connected across the two legs. The input
AC is wired from TB2 through three
circuit breakers, CB2, CB3, and CB4, to
the rest of the transmitter. CB2 is a 10amp circuit breaker that supplies the AC
voltage to the IEC outlet strip (A2-A1)
that is connected into the VHF exciter,
the (optional) receiver tray, and any
other optional accessories. CB3 is a 20amp circuit breaker that supplies AC
through J5 to the (A6) VHF amplifier tray
#1. CB4 is a 20-amp circuit breaker that
supplies AC through J6 to the (A7) VHF
amplifier tray #2. When the VHF exciter
circuit breaker is switched on, +12 VDC
is supplied to the VHF amplifier trays for
the operation of the LED status indicators
in the tray.
2.5 Maintenance
The 430B is designed with components
that require little or no periodic
maintenance except for the routine
cleaning of the fans and the front panels
of the trays.
The amount of time between cleanings
depends on the conditions within the
transmitter room. While the electronics
have been designed to function even if
covered with dust, a heavy buildup of
dust, dirt, or insects will affect the
cooling of the components. This could
lead to a thermal shutdown or premature
failure of the affected trays.
When the front panels of the trays
become dust covered, the top covers
should be removed and any accumulated
foreign material should be removed. A
vacuum cleaner, utilizing a small wandtype attachment, is an excellent way to
suction out the dirt. Alcohol and other
cleaning agents should not be used
unless you are certain that the solvents
will not damage components or the silkscreened markings on the trays and
boards. Water-based cleaners can be
used, but do not saturate the
components. The fans and heatsinks
should be cleaned of all dust or dirt to
permit the free flow of air for cooling
purposes.
It is recommended that the operating
parameters of the transmitter be
recorded from the meters on the trays
and the system metering control panel at
least once a month. It is suggested that
this data be retained in a rugged folder
or envelope. A sample format for a log
sheet is provided in Appendix B.
Photocopies of the log sheet should be
made to allow you to make continued
data entries.
2.6 Remote Interface Connections
The remote interface co nnections listed in
Table 2-10 are made to the (A12) A/V
input and remote interface assembly,
mounted facing the rear near the top of
the cabinet. The remote connections are
made to jack J9, 37 pos “D” Conn., and
jack J10, 25 pos “D” Conn., on the
assembly. Refer to the transmitter
interconnect drawing (1303857) for
verification of the remote connections.
430B, Rev. 0 2-7
1000 Watt VHF High Band Transmit ter Chapter 2, System Description,
Maintenance and Remote Interface Connections
Table 2-10. 430B Remote Interface Connections to (A12) the A/V Input
and Remote Interface Assembly
FUNCTION
Transmitter Enable Interlock J9-21
Transmitter Enable Interlock
Rtn.
Transmitter Standby
(Disable)
Transmitter
Standby/Operate Rtn.
Transmitter Operate
(Enable)
Transmitter Manual J9-15 Contact closure
Transmitter Auto/Manual
Rtn.
Transmitter Auto J9-17 Contact closure
Power Level Raise (Optional) J9-27 Contact closure
Pwr Lvl Raise/Lower Rtn
(Optional)
Power Level Lower
(Optional)
Modulator Select (Optional) J9-31 Contact closure
Modulator Select Rtn
(Optional)
Transmitter Operate
(Enable) Ind.
Operate/Standby Ind.
Return
Transmitter Standby
(Disable) Ind.
Transmitter Auto Indicator J9-18 50 mA max current sink
Auto/Manual Indicator
Return
Transmitter Manual
Indicator
REMOTE JACK/PIN
NUMBER
J9-22
Remote Control Commands
J9-9 Contact closure
J9-10
J9-11 Contact closure
J9-16
J9-28
J9-29 Contact closure
J9-32
Remote Status Indicati ons
J9-12 50 mA max current sink
J9-13
J9-14 50 mA max current sink
J9-19
J9-20 50 mA max current sink
INTERFACE TYP E
J9-21 and J9-22 must be
jumpered together for
normal operation. The
(1176-1038) jumper jack
should be used.
430B, Rev. 0 2-8
1000 Watt VHF High Band Transmit ter Chapter 2, System Description,
Maintenance and Remote Interface Connections
FUNCTION
VSWR Cutback Indicator J9-23 50 mA max current sink
VSWR Cutback Indicator
Return
Video Loss (Fault) Indicator J9-25 50 mA max current sink
Video Loss (Fault) Ind. Rtn. J9-26
Receiver Fault (Optional) J9-30
Visual Output Power J9-1
Visual Output Power Rtn J9-2
Aural Output Power J9-3
Aural Output Power Rtn J9-4
Reflected Power J9-5
Reflected Power Rtn J9-6
Exciter Output Power J9-7
Exciter Output Power Rtn J9-8
Forward Output Power (A6)
VHF High Band Amp
Forward Output Power (A6)
Rtn
Reflected O/P Power (A6)
VHF High Band Amp
Reflected O/P Power (A6)
Rtn
Forward Output Power (A7)
VHF High Band Amp
Forward Output Power (A7)
Rtn
Reflected O/P Power (A7)
VHF High Band Amp
Reflected O/P Power (A7)
Rtn
REMOTE JACK/PIN
NUMBER
J9-24
Remote Metering
J10-1
J10-2
J10-3
J10-4
J10-6
J10-7
J10-8
J10-9
INTERFACE TYP E
1V full scale at 1kΩ source
resistance
1V full scale at 1kΩ source
resistance
1V full scale at 1kΩ source
resistance
1V full scale at 1kΩ source
resistance
1V full scale at 1kΩ source
resistance
1V full scale at 1kΩ source
resistance
1V full scale at 1kΩ source
resistance
1V full scale at 1kΩ source
resistance
430B, Rev. 0 2-9
1000 Watt VHF High Band Transmitter Chapter 3, Installation and Setup Procedures
Chapter 3
Installation and Setup Procedures
There are special considerations that
need to be taken into account before the
430B can be installed. For example, if the
installation is completed during cool
weather, a heat -related problem may not
surface for many months, suddenly
appearing during the heat of summer.
This section provides planning
information for the installation and set up
of the transmitter.
3.1 Site Considerations
The transmitter requires an AC input line
of 220 VAC with a rating of 40 amps for
the transmitter. Make sure that the
proposed site for the transmitter has the
necessary voltage requirements.
The 430B is designed and built to provide
long life with a minimum of maintenance.
The environment in which it is placed is
important and certain precautions must
be taken. The three greatest dangers to
the transmitter are heat, dirt, and
moisture. Heat is usually the greatest
problem, followed by dirt, and then
moisture. Over-temperature can cause
heat-related problems such as thermal
runaway and component failure. Each
amplifier tray in the transmitter contains
a thermal interlock protection circuit that
will shut down that tray until the
temperature drops to an acceptable level.
A suitable environment for the
transmitter can enhance the overall
performance and reliability of the
transmitter and maximize revenues by
minimizing down time. A properly
designed facility will have an adequate
supply of cool, clean air, free of airborne
particulates of any kind, and no
excessive humidity. An ideal environment
will require temperature in the range of
40° F to 70° F throughout the year,
reasonably low humidity, and a dust -free
room. It should be noted that this is
rarely if ever attainable in the real world.
However, the closer the environment is
to this design, the greater the operating
capacity of the transmitter.
The fans and blowers designed and built
into the transmitter will remove the heat
from within the trays, but additional
means are required for removing this
heat from the building. To achieve this, a
few issues need to be resolved. The first
step is to determine the amount of heat
to be removed from the transmitter
room. There are generally three sources
of heat that must be considered. The first
and most obvious is the heat from the
transmitter itself. This can be determined
by subtracting the average power to the
antenna (700 watts) from the AC input
power (3800 watts). This number in
watts (3100) is then multiplied by 3.41,
which gives 10,571 BTUs that needs to
be removed every hour. 12,000 BTUs per
hour equals one ton, so a 1 ton air
conditioner will cool a 1000 watt
transmitter.
The second source of heat is other
equipment in the same room. This
number is calculated in the same way as
the equation for BTUs. The third source
of heat is equally obvious but not as
simple to calculate. This is the heat
coming through the walls, roof, and
windows on a hot summer day. Unless
the underside is exposed, the floor is
usually not a problem. Determining this
number is usually best left up to a
qualified HVAC technician. There are far
too many variables to even estimate this
number without reviewing the detailed
drawings of the site that show all of the
construction details. The sum of these
three sources is the bulk of the heat that
must be removed. There may be other
sources of heat, such as personnel, and
all should be taken into account.
Now that the amount of heat that must
be removed is known, the next step is to
430B, Rev. 0 3-1
1000 Watt VHF High Band Transmitter Chapter 3, Installation and Setup Procedures
determine how to accomplish this. The
options are air conditioning, ventilation,
or a combination of the two. Air
conditioning is always the preferred
method and is the only way to create
anything close to an ideal environment.
Ventilation will work quite well if the
ambient air temperature is below 100° F,
or about 38° C, and the humidity is kept
at a reasonable level. In addition, the air
stream must be adequately filtered to
ensure that no airborne particulates of
any kind will be carried into the
transmitter. The combination of air
conditioning for summer and ventilation
during the cooler months is acceptable
when the proper cooling cannot be
obtained through the use of ventilation
alone and using air conditioning
throughout the year is not feasible.
Caution: The use of air conditioning
and ventilation simultaneously is not
recommended. This can cause
condensation in transmitters. For
tube type transmitters, this can be
especially serious if the
condensation forms in the tube
cavity and creates damaging arcs.
The following precautions should be
observed regarding air conditioning
systems:
1. Air conditioners have an ARI
nominal cooling capacity rating. In
selecting an air conditioner, do not
assume that this number can be
equated to the requirements of
the site. Make certain that the
contractor uses the actual
conditions that are to be
maintained at the site in
determining the size of the air
conditioning unit. With the desired
conditioned room temperature
under 80° F, the unit must be
derated, possibly by a substantial
amount.
2. Do not have the air conditioner
blowing directly onto the
transmitter. Condensation may
occur on, or worse in, the
transmitter under certain
conditions.
3. Do not isolate the front of the
transmitter from the back with the
thought of air conditioning only
the front of the unit. Cooling air is
drawn in at the front of all
transmitters and in the front and
back of others. Any attempt to
isolate the front from the rear will
adversely affect the flow of cooling
air.
4. Interlocking the transmitter with
the air conditioner is
recommended to keep the
transmitter from operating without
the necessary cooling.
5. The periodic cleaning of all filters
is a must.
When using ventilation alone, the
following general statements apply:
1. The blower, with attendant filters,
should be on the inlet, thereby
pressurizing the room and
preventing dirt from entering the
transmitter.
2. The inlet and outlet vents should
be on the same side of the
building, preferably the leeward
side. As a result, the pressure
differential created by wind will be
minimized. Only the outlet vent
may be released through the roof.
3. The inlet and outlet vents should
be screened with 1/8-inch
hardware cloth (preferred) or
galvanized hardware cloth
(acceptable).
4. Cooling air should enter the room
as low as practical but in no case
higher than four feet above the
floor. The inlet must be located
where dirt, leaves, snow, etc., will
430B, Rev. 0 3-2
1000 Watt VHF High Band Transmitter Chapter 3, Installation and Setup Procedures
not be carried in with the cooling
air.
5. The exhaust should be located as
high as possible. Some ducting is
usually required to insure the
complete flushing of heated air
with no stagnant areas.
6. The filter area must be large
enough to insure a maximum air
velocity of 300 feet per minute
through the filter. This is not a
conservative number but a neverexceed number. In a dusty or
remote location, this number
should be re duced to 150 CFM.
7. The inlet and outlet(s) must have
automatic dampers that close any
time the ventilation blower is off.
8. In those cases in which
transmitters are regularly off for a
portion of each day, a
temperature-differential sensor
that controls a small heater must
be installed. This sensor will
monitor inside and outside
temperatures simultaneously. If
the inside temperature falls to
within 5° F of the outside
temperature, the heater will come
on. This will prevent condensation
when the ventilation blower comes
on and should be used even in the
summer.
9. A controlled-air bypass system
must be installed to prevent the
temperature in the room from
falling below 40° F during
transmitter operation.
10. The blower should have two
speeds, which are thermostatically
controlled, and be interlocked with
the transmitter.
11. The blower on high speed must be
capable of moving the required
volume of air into a half inch of
water pressure at the required
elevation. The free air delivery
method must not be used.
12. Regular maintenance of the filters,
if used, can not be
overemphasized.
13. Transmitters should not rely on
the internal blower to vent the
cooling air at elevations above
4000 feet. For external venting,
the air vent on the cabinet top
must be increased to an 8”
diameter for a 1kW transmitter.
An equivalent rectangular duct
may be used but, in all cases, the
outlet must be increased by 50%
through the outlet screen.
14. It is recommended that a site plan
be submitted to Axcera for
comments before installation
begins.
In calculating the blower requirements,
filter size, and exhaust size, if the total
load is known in watts, 2000 CFM into ½
inch of water will be required for each
5000 watts. If the load is known in BTUs,
2000 CFM into ½ inch of water will be
required for each 17,000 BTUs. The inlet
filter must be a minimum of seven
square feet, larger for dusty and remote
locations, for each 5000 watts or 17,000
BTUs. The exhaust must be at least four
square feet at the exhaust screen for
each 5000 watts or 17,000 BTUs.
The information presented in this section
is intended to serve only as a general
guide and may need to be modified for
unusually severe conditions. A
combination of air conditioning and
ventilation should not be difficult to
design (see Figure 3-1). System
interlocking and thermostat settings
should be reviewed with Axcera. As with
any equipment installation, it is always
good practice to consult the
manufacturer when questions arise.
Axcera can be contacted at (724) 873-
8100.
430B, Rev. 0 3-3
1000 Watt VHF High Band Transmitter Chapter 3, Installation and Setup Procedures
Figure 3-1. 1 kW Minimum Ventilation Configuration
3.2 Unpacking the Cabinet and Trays
Note: Air conditioning and any
related heat exhaust ducts should be
in place before continuing with the
installation of the transmitter.
Thoroughly inspect the cabinets and all
other materials upon their arrival. Axcera
certifies that upon leaving our facility the
equipment was undamaged and in proper
working order. The shipping containers
should be inspected for obvious damage
that indicates rough handling. Check for
dents and scratches or broken switches,
meters, or connectors. Any claims
against in-transit damage should be
directed to the carrier. Inform Axcera as
to the extent of any damage as soon as
possible.
Remove the cabinet and the trays from
the crates and boxes. Remove the straps
that hold the cabinet to the shipping skid
and slide the cabinet from the skid.
Remove the plastic wrap and foam
protection from around the cabinet. Do
not remove any labeling or tags from any
cables or connectors; these are
identification markers that make
assembly of the transmitter much easier.
Remove the two L-brackets, mounted on
the front panel rails, which held the trays
in place during shipment. The trays are
mounted in the cabinet using Chassis
Trak cabinet slides as shown in Figure
3-2. The tra y slides are on the top and
the bottom of the VHF amplifier trays and
on the sides of the VHF exciter tray.
Inspect the trays for any loose hardware
or connectors, tightening as needed.
430B, Rev. 0 3-4
1000 Watt VHF High Band Transmitter Chapter 3, Installation and Setup Procedures
Figure 3-2. Chassis Trak Cabinet Slides
Open the rear door. Inspect the interior
of the cabinet for packing materials and
carefully remove any packing materials
that are found. Slowly slide each tray in
and out to verify that they do not rub
against each other and have no
restrictions to free movement.
3.3 Instal ling the Cabinets and Trays
It may be necessary to adjust the
position of the trays to keep them from
rubbing. This is accomplished by
loosening the cabinet slide mounting
bolts that hold the front of the slide to
the mounting frame of the cabinet and
moving the tray up or down, as needed,
to correct for the rubbing.
The air intake to the 1000 watt
transmitter is only intended for room air.
The cabinet should be positioned for
adequate air intake and exhaust; the
opening of the rear door, if present;
access to the trays, including sliding
them out for testing; the main AC
hookup; and the installation of the output
transmission line. The cabinet should be
grounded using copper strapping
material and should be permanently
mounted to the floor of the site using the
holes in the bottom of the cabinet.
3.4 Main AC Connection
Once the cabinet is in place, and the
trays are checked for damage, the main
AC hookup can be made.
Caution: Before connecting the 220
VAC, make certain that all of the
circuit breaker s associated with the
transmitter have been switched off.
The main AC input circuit to the 1000
watt transmitter should be a 40-amp,
220 VAC line, using AWG 6 wire, inside of
a 1-1/4-inch conduit.
The 220 VAC input connections are made
to terminal bloc k TB1, which is part of
the AC distribution panel, near the upper
right hand, rear portion of the cabinet.
Connect Line 1 to TB1 -1A, Line 2 to TB14A and chassis ground to TB1 -3A.
The output of the bandpass filter
assembly, which is a “1-5/8” EIA
connector, should connect to the
transmission line for the antenna system.
This completes the unpacking and
installation of the 430B 1000 watt VHF
television transmitter. Refer to the setup
430B, Rev. 0 3-5
1000 Watt VHF High Band Transmitter Chapter 3, Installation and Setup Procedures
and operation procedures that follow
before applying power to the transmitter.
3.4 Setup and Operation
Initially, the transmitter should be turned
on with the RF output at (A9-A5-J2) the
bandpass filter assembly terminated into
a dummy load of at least 1000 watts. If a
load is not available, check that the
output of the bandpass filter assembly is
connected to the antenna.
Connect the baseband balanced audio
input to the terminal block TB1 or the
composite audio input to BNC jack J6 on
the A/V input & remote interface
assembly, located facing the rear of the
cabinet near the top. The baseband
audio input can remain connected when
using the 4.5 MHz composite input
without affecting the operation of the
transmitter. Connect the baseband video
input to BNC jack J2 also on the A/V I/P
& remote interface assembly, if the
(optional) 4.5 MHz composite input kit is
purchased, connect the 4.5-MHz
composite input to the BNC jack J2. To
use the 4.5 MHz composite input, the 4.5
MHz composite input must be connected
to J2 and the baseband select must be
removed from J7-6 and J7-7 on the rear
of the VHF Exciter tray. To use the
baseband video and audio inputs, the
baseband video input must be connected
to J2, the baseband audio must be
connected to the proper jack, and the
baseband select must be connected from
J7-6 and J7-7.
Switch on the main AC, VHF exciter, and
the amplifier #1 and amplifier #2 circuit
breakers on the AC distribution panel
facing the rear of the cabinet and
mounted behind the rear door. On the
VHF exciter tray, switch the
Operate/Standby switch to Standby and
the Auto/Manual switch to Manual.
NOTE: Normal operation of the
transmitter is in Automatic. Automatic
operation uses the video input to the VHF
exciter as an Operate/Standby switch. In
Auto, if the input video is lost for
approximately 7 seconds, the transmitter
will automatically revert to Standby and,
when the video signal is restored, the
transmitter will quickly return to Operate.
Move the Operate/Standby switch on the
VHF exciter tray to Operate. Observe the
power supply reading, +28 V, on the
front panel of the VHF amplifier trays.
Note: If the transmitter does not switch
to Operate when the Operate/Standby
switch is placed in Operate, check that an
external interlock plug, with a jumper
wired from pins 21 to 22, is connected to
jack J9 on the (A12) A/V input and
remote interface assembly.
On the VHF exciter tray, look at the front
panel meter reading in the % Visual
Power position; it should read 100%. If
necessary, readjust the screwdriver
adjust power pot on the front panel of
the VHF exciter for 100%. As the power
level is being checked, observe the meter
reading in the % Reflected Power
position. If the % Reflected Power is
very high, above 10%, a problem exists
with the output coaxial lines and they will
need to be checked. A center bullet
missi ng from the coax lines or loose bolts
on the connections can cause this
problem. Return the Operate/Standby
switch to Standby.
The gain and phase controls on the front
panels of the individual VHF amplifier
trays were adjusted at the factory to
obtain an output of 100% for the
transmitter and should not need to be
readjusted. The front panel readings on
the individual VHF amplifier trays may
not be the same. Refer to the Test Data
Sheet for the transmitter to compare the
final readings from the factory with the
readings on each of the trays after the
setup. They should be very similar. If a
reading is off by a significant amount,
refer to the phasing and power
adjustment procedures for the VHF
amplifier trays in Chapter 5, Detailed
Alignment Procedures, of this manual
before trying to make any adjustments.
430B, Rev. 0 3-6
1000 Watt VHF High Band Transmitter Chapter 3, Installation and Setup Procedures
If a dummy load is connected to the
transmitter, switch the unit to Standby
and switch off the main AC circuit
breaker. Remove the dummy load and
make all of the connections that are
needed to connect the transmitter to the
antenna. Switch the main AC circuit
breaker on and the Operate/Standby
switch to Operate. Adjust the output
power screwdriver pot to achieve an
output of 100%.
If the transmitter is already connected to
the antenna, check that the output is
100%. If necessary, adjust the power
screwdriver pot.
This completes the transmitter setup and
operation procedures for the 430B VHF
solid state transmitter. The transmitter
can now be operated normally.
If a problem occurred during the setup
and operation procedures, refer to
Chapter 5, Detailed Alignment
Procedures, of this manual for more
information.
430B, Rev. 0 3-7
Loading...