Technalogix TAU500 Users Manual

TAU-500

POWER AMPLIFIER

NEW

ADVENTURES

IN

BROADCASTING

Technalogix

You’ve already unpacked it, haven’t you? You’ve unpacked it and plugged
it in and turned it on and fiddled with the knobs. No? Okay, good. Please
take a few minutes to read the manual and familiarize yourself with your
new Technalogix power amplifier.

We believe that this manual, and of course our equipment, should be
everything you need to get on the air with superb broadcast quality video.
We understand that a capable and confident user will get the most out of
our product and we have made every attempt to educate readers of all
technical levels. If there is something that is not clear, or you require
further information, please do not hesitate to contact us and we’ll be glad
to help out.

Technalogix Ltd.
#4, 8021 Edgar Industrial Place
Red Deer, Alberta, Canada
T4P 3R3
Phone: [phone]
Fax: [phone]
URL: www.technalogix.ca
Email: [e-mail]

[e-mail]

We truly appreciate that you have chosen us as your television broadcast
system supplier. Happy viewing.

Table of Contents

SECTION I- SAFEGUARDS...............................................................................................I-1

SAFETY AND FIRST AID.....................................................................................................I-2

OPERATING SAFEGUARDS ................................................................................................I-3

SECTION II - WARRANTY ..............................................................................................II-1

SECTION III - OVERVIEW..............................................................................................III-1

STANDARD FEATURES....................................................................................................III-1

PRINCIPLE OF OPERATION..............................................................................................III-2

BLOCK DIAGRAM.............................................................................................................III-3

SPECIFICATIONS..............................................................................................................III-5

SECTION IV - RF COMPONENTS................................................................................IV-1

AMPLIFIER PALLETS.......................................................................................................IV-1

SPLITTER /COMBINER.....................................................................................................IV-4

DIRECTIONAL COUPLER.................................................................................................IV-4

I SOLATOR ....................................................................................................................... IV-4

FILTER............................................................................................................................IV-4

SECTION V - POWER SUPPLY SECTION......................................................................V-1

SECTION VI - MONITOR AND CONTROL SYSTEM.......................................................VI-1

CONTROL BOARD OVERVIEW (SERIES II -I)................................................................... VI-1

POWER SUPPLY COMPONENTS.....................................................................................VI-1

INTERFACE COMPONENTS .............................................................................................VI-2

SIGNAL CONDITIONING COMPONENTS ..........................................................................VI-3

DISPLAY COMPONENTS .................................................................................................VI-4

MICROCONTROLLER COMPONENTS...............................................................................VI-5

FAULT SHUTDOWN.........................................................................................................VI-6

REMOTE PORT...............................................................................................................VI-7

BILL OF MATERIALS.......................................................................................................VI-8

SCHEMATICS ................................................................................................................VI-10

SECTION VII - MECHANICAL SECTION......................................................................VII-1

SECTION VIII - INSTALLATION..................................................................................VIII-1

BUILDING RECOMMENDATIONS....................................................................................VIII-1

HEATING AND COOLING REQUIREMENTS ....................................................................VIII-2

ELECTRICAL SERVICE RECOMMENDATIONS................................................................VIII-3

ANTENNA AND TOWER RECOMMENDATIONS...............................................................VIII-4

SHELTER SECURITY .....................................................................................................VIII-5

UNPACKING AND I NSPECTION......................................................................................VIII-6

LOCATION AND FUNCTION OF CONTROLS AND CONNECTORS (TAU-500 POWER

AMPLIFIERS).................................................................................................................VIII-7

LOCATION AND FUNCTION OF CONTROLS AND CONNECTORS (POWER SUPPLY)......VIII-9

INITIAL HOOK UP ........................................................................................................VIII-11

SECTION IX - OPERATING PROCEDURE.....................................................................IX-1

SECTION X - MAINTENANCE AND TROUBLESHOOTING...............................................X-1

TROUBLESHOOTING ........................................................................................................X-2

Section I - Safeguards

General Safeguards

This section is written as a general guide to keep all 5 fingers on your hand and is intended for those having
previous knowledge and experience with these kinds of equipment. It is not intended to contain a complete
statement of all safety precautions, which should be observed by personnel using this or other electronic
equipment.

DOCUMENTATION - Read, retain and follow instructions before operating the equipment. There is a
lot of useful information in the manual, and besides, we spent a lot of time writing it!

ENVIRONMENT - To reduce the risk of fire or electric shock, do not expose this equipment to rain,
moisture, or rye and sodas at the company Christmas party. Refer all servicing to qualified service
personnel.

SERVICING - Do not attempt to service this equipment yourself as opening or removing covers can
result in a warm tingly feeling and will void the warranty. Refer all servicing to qualified service
personnel.

I-1

Safety and First Aid

Personnel engaged in the installation, operation, maintenance, or servicing of electronic equipment are exposed
to the hazard of high voltage. It is imperative that all safety regulations and precautions are consistently
observ ed. Knowledge of first aid procedures is recommended. The following information is presented as a
reference only.

• At all times, avoid placing any part of the body in series between ground and circuit points, whether power is
on or off.

• Dangerous voltage may be present in equipment even though power is off. Do not open the cabinet. Refer
servicing to qualified service personnel.

• It is the duty of all personnel to be prepared to give adequate emergency first aid treatment and thereby
prevent avoidable loss of life.

• There are three principle degrees of burns, recognizable as follows:

• a first-degree burn reddens the skin.

• a second-degree burn blisters the skin.

• a third degree burn chars the flesh and frequently places the victim in a state of shock accompanied

by respiratory paralysis.

• Respiratory paralysis can cause death by suffocation within seconds. It is imperative that the approved
methods of artificial respiration are initiated immediately and continue until the victim’s breathing is normal.

• A muscular spasm of unconsciousness may render the victim unable to break free of the electric power. If
this is the case, turn the power off immediately.

DO NOT TOUCH THE VICTIM OR YOU MAY SHARE THE SAME PREDICAMENT.

• If the power cannot be turned off immediately, very carefully loop a dry rope, article of clothing, length of
strong cloth or a rolled-up newspaper around the victim and pull the victim free of the power source.
Carefully avoid touching the victim or clothing.

• Once free of the power source, the victim must be placed in a reclining position and covered with a
blanket or newspapers to keep warm. At the first opportunity, enlist help in summoning a doctor. If a
doctor cannot be summoned, transport the victim to the doctor or a hospital. Be sure the victim is kept
well covered and warm while awaiting professional treatment.

I-2

Operating Safeguards

It is a known fact that our broadcast transmitters and translators enjoy 50-ohm load impedances. So much
so, that it is imperative you maintain 50-ohm impedances throughout your system. In return, your equipment
will provide you with maximum power transfer to the antenna and decreased reflected power heading back
towards the amplifier pallets, reducing the amount of magic smoke that gets let out of the power amplifier.
Before anything is turned on, ensure that there is a 50-ohm path from the output of each stage to the input
of the next, all the way to the antenna.

In addition to maintaining proper 50-ohm impedances throughout the signal chain, it is also important,
whenever possible, to make sure the RF drive going to the input of the power amplifier is removed before
turning on or turning off the DC power supply. This is because all of the RF transistors used in the individual
amplifier pallets are fabricated with LDMOS (Laterally Diffused Metal Oxide Semiconductor) technology.
Nice and linear yes, but they do not like to make any RF power when their supply voltages are not within a
specific range. When you first turn your power amplifier on or off, the DC power supply’s output voltage may
take a while to stable out to a safe operating voltage. Ten seconds wait before applying the RF drive will
ensure no issues arise.

Our power amplifiers are designed to reliably generate a specific RF output power. Failing to adhere to
overdriven amplifier warnings can decrease the reliability of your system, and frankly, makes our repair
department busy and grumpy. If you need to transmit to a little larger coverage, you are better off increasing
antenna gain, and more importantly, antenna height above average terrain. On TV and FM broadcast
frequencies, insufficient antenna height puts an upper limit on your range, regardless of power levels, as the
distance from your antenna to the radio horizon is limited.

I-3

Section II - Warranty

Our legalese is straightforward. It is simply designed to give you peace of mind and helps you resist the
temptation to have your electronics friend try to repair your Technalogix product.

Technalogix Ltd. products have been completely tested and found to meet specifications and be in
proper operating condition. They are warranted to be free from defects in materials and workmanship
for a period of one year from the date of shipment. If the system becomes damaged in shipment and
there are obvious signs of damage to the outside of the packaging, notify your courier immediately
before that courier walks out the door.

Technalogix Ltd. will not be liable for damages of whatever nature arising out of or in connection with
the equipment or its use thereof. Technalogix does not assume responsibility for injury or damage
resulting from the practices of untrained or unqualified personnel in the handling of this equipment.

Technalogix Ltd. warranty does not include:

• misuse, neglect or accident.

• incorrect wiring and /or improper installation.

• unauthorized repairs, modifications or use in violation of instructions issued by Technalogix.

• incidental or consequential damages as a result of any defect.

• reshipment cost or insurance of the unit or replacement units or parts.

• acts of nature or terrorism.

Technalogix agrees, at our option, to remedy warranted defects or furnish a new part in exchange for
any part of a unit which, under normal installation, use and service, becomes defective. The user will
pay for transportation costs to and from the repair center. If you require technical service on the site,
the cost to you will be $800.00 per day plus air fare and meals.

II-1

To claim your rights under this warranty:

• Contact Technalogix and describe the problem in as much detail as possible. See troubleshooting
section in this manual. If a solution cannot be found at this time, it may be determined that the unit
will have to be returned to Technalogix for repair, once a Return Materials Authorization (RMA)
number is provided. Please look under our web site (www.technalogix.ca) for the RMA form
(Service) and fill it out. Either fax it to us or email to us.

• Package equipment carefully for prepaid shipment to Technalogix. Include a written description of
the problem experienced, a copy of the original invoice establishing warranty status, and the RMA.

Technalogix reserves the right to make revisions in current production of the equipment and assumes
no obligation to incorporate these changes in earlier models.

Shipping Address:
Technalogix Ltd.

ATTN: RMA#
#4, 8021 Edgar Industrial Place
Red Deer, Alberta, Canada
T4P 3R3
Ph: 403.347.5400
Made in Canada, returned for repairs

II-2

Section III – Overview

Standard Features

• Narrow output bandpass filter allows adjacent channel operation

• Front panel Liquid Crystal Display (LCD) to monitor forward and reflected RF power, and DC

voltage

• Microcontroller-based monitoring and control ensures amplifier will never be overdriven and high
VSWR will not damage amplifier

• AC circuit breaker on back panel to eliminate replacement of fuses

• All aluminium enclosure maintains power amplifier’s light weight

• Simple design using commonly available parts ensures reliable operation

• Predominate and third-order intermodulation distortion exceeds Industry Canada and FCC

specification.

III-1

Principle of Operation

The TAU -500 power amplifier supplies a 500-watt peak video signal with an aural carrier level 10 to 13
dB below visual carrier (dBc) on any of the UHF television channels 14 through 69. Please note that
channel selection must be made at time of order, as the transmitter or translator is calibrated and
tested to the channel requested and is not field tuneable. The TAU-500 power amplifier is a modular
solid-state 500-watt broadcast amplifier utilizing readily available RF components wherever possible,
thus enhancing the serviceability of the equipment.

The TAU -500 is comprised of a TECH-30U driver pallet and (2) P300 final pallets that are combined to
create 500 watts of peak visual power in addition to the aural carrier power.

The TAU-500 features ultra linear amplification and individual channel RF output bandpass filtering.
The amplifier modules are stable for high reliability and long service life.

III-2

Block Diagram

The RF signal enters through the RF Input connector on the power amplifier enclosure from the
modulator or processor. It then passes through an RF attenuator to limit the output power level of
the power amplifier and to help buffer any transients that may come into the power amplifier. After
attenuation, the signal gets preamplified through the driver pallet before the signal gets split into
(2) signals for final amplification. The output of the (2) final amplifier pallets get combined and
passes through an isolator and a bandpass filter. Finally, the signal passes through a dual
directional coupler for monitoring purposes before heading out to an antenna for broadcast.

III-3

P300-UHF FINAL

2-WAY

SPLITTER

TECH-30U

RF INPUT RF OUT

ATTENUATION

A=+38dB min.

A=-0.2dB typical

A=14dB min.

2-WAY

COMBINER

A=-0.2dB typical

CIRCULATOR

A=-0.5dB typical

V

DIRECTIONAL COUPLER

V

A=-0.05dB typical

V

i

To Wattmeter
and Antenna

P300-UHF FINAL

50 OHM
TERMINATION

A=14dB min.

TAU-500 Block Diagram

Rev ID

Date: May 24, 2005 Page: 1 of 1

Specifications

The following specifications were taken with a Technalogix modulator/processor. Should a different
modulator or processor be used, specifications could vary. For this reason, we recommend that any
different modulator/processor be shipped to Technalogix so the system can be matched and set up
optimally. In addition, the audio/video ratio the input to the power amplifier needs to be –10 dB in order
for the software and LCD readout to be accurate.

RF Characteristics

Frequency range any specified UHF Channel 14 to 60**
Frequency Response (one channel) ±0.5 dB
Frequency Stability ±250 Hz
Selectivity 60 dB (adjacent channel)
Minimum Input Level 0 dBmV
Rated Visual Output Power 500 Watts
Rated Aural Output Power 10% of peak visual power
IF Output Level +35 dBmV nominal
Input Impedance 75 Ohms
Output Impedance 50 Ohms
Harmonics > 60 dB below rated power
Predominant Intermodulation Distortion dBc = decibels below visual carrier

+ 920 kHz

- 920 kHz

+ 2.66 MHz

- 2.66 MHz
+ 5.42 MHz
+ 7.16 MHz

3rd Order Intermodulation Distortion

+ 4.5 MHz
+ 9.0 MHz

All others

Spurious Emissions > -60 dBc
** Stand-alone power amplifier will operate from channels 14-69.
PAL Video Characteristics

Input Level to modulator (for 87.5% modulation) 1.0 V

Differential Phase (at 87.5% modulation) ±2 Degrees

Differential Gain (at 87.5% modulation) 2%

Group Delay < ±40 nS

Video Group Delay Pre-emphasis Conforms to IC/FCC specifications

K-Factor 1.9% for 2T Pulse

Hum and Noise > 60 dB below rated power

> -53 dBc
> -53 dBc
> -53 dBc
> -53 dBc
> -53 dBc
> -53 dBc

> -60 dBc
> -60 dBc
> -60 dBc

PP

III-5

Aural Characteristics

Input Level for 25 kHz Deviation 0.3 V

Frequency Response (Standard Pre-emphasis) ±1 dB

Harmonic Distortion (25 kHz Deviation) < 1% 50 Hz to 15 kHz

Amplitude Modulation Noise > 50 dB

Frequency Modulation Noise > 60 dB

Intercarrier Stability ±250 Hz

Physical Characteristics

Power Requirements

PP

Operating Temperature

Dimensions

Power Supply

TAU-500 Power Amplifier

Power Supply

230 VAC, 10 A

0 - 50°C

W-19" flange (17” encl.), D-25-¼", H-8-¾” (5U)

W-19" flange (17” encl.), D-2-¼", H-7” (4U)

AC

III-6

Section IV – RF Components

Amplifier Pallets

The TECH -30U driver pallet consists of (2) separate printed circuit board stages – The first stage is an
ultra-linear class-A stage with (3) gain sections providing a typical adjustable power gain of 26dB to
37dB at 10-watts peak. This stage typically draws 2.5 Adc quiescent and a maximum drain current of 5
Adc. The second stage is a linear class AB stage with a typical gain of 13 dB. This stage typically
draws 1.0 Adc quiescent and a maximum drain current of 10 Adc. The currents on both stages can be
found by measuring the voltage drop across the +30 Vdc input and the I sense connector. The
resistance separating these connections is 0.01 ohms, providing a 10 mV per ampere ratio.

The P300-UHF pallets used in the final amplification stage use LDMOS (Laterally Diffused Metal Oxide
Semiconductor) technology. LDMOS technology offers higher gain, efficiency and linearity over
standard MOSFET and Bipolar devices and enhances ruggedness and reliability. LDMOS transistors
have the added advantage of not having BEO (Beryllium Oxide) in their construction. The P300-UHF
amplifier pallets have a typical gain of 15dB (14dB minimum) and draw no more than 23Adc. Currents
for these pallets must be measured with an ammeter in series with the power supply lead.

Each of the amplifier pallets is connectorized to optimize servicing and accessibility. All amplifier pallets
must have the transistor drain voltages reach at least 26Vdc before the RF drive is applied.

IV-1