Technalogix TAV25H, TAV25L Users Manual

POWER AMPLIFIER

ADVENTURES

BROADCASTING

TAV-25

NEW

IN

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

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

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

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

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

CONTROL BOARD OVERVIEW (INSIGHT)........................................................................VI-1

USER I NTERFACE MODULE............................................................................................VI-1

COUPLER CONDITIONING MODULE................................................................................ VI-2

RF CONDITIONING MODULE ..........................................................................................VI-3

TEMPERATURE SENSOR MODULE ................................................................................. VI-4

TXNET MODULE.............................................................................................................. VI-5

REMOTE PORT...............................................................................................................VI-6

FAULT SHUTDOWN.........................................................................................................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 (TXV-25 POWER

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

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 observed. 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

• RF/EMI filtering on AC entry plug

• 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 TAV-25 power amplifier supplies a 25-watt peak video signal with an aural carrier level 10 to 13 dB
below visual carrier (dBc) on any of the VHF television channels 2 through 13. 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 TAV-25 power amplifier is a modular
solid-state 25-watt broadcast amplifier utilizing readily available RF components wherever possible,
thus enhancing the serviceability of the equipment.

The TAV-25 is comprised of a VHFTV-25-L pallet for low -band VHF frequencies or VHFTV-25-H pallet
for high-band VHF frequencies.

The TAV-25 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 is amplified through the VHFTV-25 driver before the signal passes through
a bandpass filter. Finally, the amplified signal passes through a dual directional coupler for
monitoring purposes. After the directional coupler, the signal exits the power amplifier enclosure
before heading out to an antenna for broadcast.

III-3

UHFTV-25

CIRCULATOR

FILTER

DIRECTIONAL

COUPLER

RF INPUT

ATTENUATOR

A=+40dB typ. low band VHF
A=+34dB typ. high band VHF

V

A=-0.5dB typ.

50-OHM

TERMINATION

A=-0.6dB typ.

RF OUT

V

A=-0.05dB typ.

V

TO WATTMETER
AND ANTENNA

TAV-25 Block Diagram

Rev ID

Date: May 23, 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 VHF Channel 2 to 13
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 25 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

NTSC 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

21.25",

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

TAV-25 Power Amplifier

TAV-25 Power Amplifier

115 VAC, 4 A

230 VAC, 2 A

AC or

0 - 50°C

W-19" flange (17” encl.) , D-

H-5.25” (3U)

AC

III-6

Section IV – RF Components

Amplifier Pallets

The VHFTV-25 pallet is a two stage ultra linear class-A linear pallet. The VHFTV-25-L has a typical
gain of 40dB and the VHF TV-25-H has a typical gain of 34dB. These pallets draw no more than

3.0Adc total drain current (the exact bias and drain currents of your system are found in the spec
sheet supplied with each manual). The quiescent and drain currents can be measured on the VHFTV­25 pallet by measuring the voltage drop across the current sense resistor found directly at the DC
power supply lead input to the pallet. This resistance is 0.01-ohms, providing a 10mV per ampere ratio.

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

IV-1

TECHNALOGIX LTD.

25 W UHF HI BAND DRIVER

P25-UHF

R.S. MCDONALD

14 SEPTEMBER, 2000

A

A

1

1

A

A11

TECHNALOGIX LTD.

25 W UHF LO BAND DRIVER

P25-UHF-L

R.S. MCDONALD

14 SEPTEMBER, 2000

23

Filter
The passive bandpass filter rejects spurious and harmonic output products and passes the VHF

channel RF output. The cavity resonator uses aperture coupling and is a linear resonator design.
Typical insertion loss is 0.6 dB to 1.0 dB depending on channel frequency. Average roll off is –33 dBc
at a point 4.5 MHz below the peak visual carrier frequency and –30 dBc 9.0 MHz above the peak visual
carrier frequency. The filter is DC grounded on both the input and output for additional lightning
protection.

Directional Coupler

The Technalogix dual directional couplers provide DC voltages proportional to forward and reflected
RF power monitoring. These analog voltages are converted for processing using analog-to-digital
converters and provide the control system with valuable data for monitoring purposes. The directional
couplers installed in the power amplifier and filter enclosures have peak detection circuits on the
forward RF power side of the coupler and average detection circuits on the reflected RF power side of
the coupler. This is to allow the end user to set power in a manner that is more independent of
modulation and closer to a true tip-of-sync meter. Hence the readings of the displays in the power
amplifier system are peak for forward and average for reflected. Output power should be set following
the operating procedure found elsewhere in this manual. The directional coupler has a typical
insertion loss of 0.5dB and its Type N connectors can handle 1,500 watts peak.

IV-4