Manuale Tecnico

Manuale Tecnico
Technical Manual
(INSTALLATION & USE)
1 kW UHF TV RF AMPLIFIER ETL0480TBD
EuroTel S.r.l.
Via della Birona 30/32
20052 Monza, Italy
Tel. +39 039 230 2645 – Fax +39 039 230 2650
E-Mail salesmail@eurotel.it – Web http://www.eurotel.it
EUROTEL - ITALY
ETL0480TBD
Technical Manual
1 kW UHF B IV-V RF POWER AMPLIFIER ETL0480TBD
TABLE OF CONTENTS
Section A- GENERAL INFORMATION .......................................................................................3
I - AMENDMENT RECORD SHEET ........................................................................................ 3
II - APPROVAL RECORD SHEET ............................................................................................ 3
III - WARNINGS .................................................................................................................. 4
1 ) FIRST AID IN CASE OF ELECTRIC SHOCK ................................................................. 4
2 ) EMERGENCY RESUSCITATION: EXPIRED AIR METHOD.............................................. 5
3 ) TREATMENT FOR BURNS.......................................................................................... 5
Section B- PURPOSE AND PLANNING INFORMATION ..............................................................6
I - INTRODUCTION ............................................................................................................ 6
II - SCOPE .......................................................................................................................... 6
III - COMPOSITION OF RF AMPLIFIER ETL0480TBD, 1 kW UHF ............................................ 7
IV - COMPOSITION OF ETL0470, RF AMPLIFIER MODULE 700 W UHF ................................ 8
V - TECHNICAL SPECIFICATIONS........................................................................................ 9
1 ) General................................................................................................................... 9
2 ) Input Parameters...................................................................................................... 9
3 ) Output Parameters................................................................................................... 9
4 ) Transmission Quality.............................................................................................. 10
5 ) Dimensions and Weight ......................................................................................... 10
VI - FUNCTIONAL DESCRIPTION....................................................................................... 11
1 ) Theory of operation of 1 kW UHF RF Amplifier ETL0480TBD .................................... 11
2 ) Theory of operation of 700 W UHF TV RF Amplifier Module ETL0470 ....................... 12
VII - RF AMPLIFIER CONFIGURATIONS & ORDERING INFORMATION................................. 14
Section C- OPERATING INFORMATION .................................................................................15
I - INSTALLATION ............................................................................................................. 15
1 ) ETL0480TBD R. F. Amplifier: mounting procedure ................................................... 15
2 ) Other connections.................................................................................................. 16
3 ) ETL0470: front panel controls, displays & connectors............................................... 17
4 ) ETL0470: rear panel connectors ............................................................................. 19
5 ) Enable IN/OUT DIN socket .................................................................................... 21
6 ) ALARMS OUT socket .............................................................................................. 21
7 ) SERIAL DATA RS-485 socket ................................................................................... 22
8 ) SERIAL DATA COM (RS-232) socket ........................................................................ 22
9 ) E-LINK SERIAL NETWORK socket............................................................................. 22
II - OPERATING PROCEDURES .......................................................................................... 23
1 ) First time operation of ETL0480TBD ........................................................................ 23
2 ) RF Amplifier ETL0470: in case of difficulty ............................................................... 24
III - ETL0470 - MULTI-FUNCTION METERING DISPLAY....................................................... 24
1 ) Alphanumeric LCD display description .................................................................... 24
2 ) Menu Description................................................................................................... 25
3 ) Entering a Menu .................................................................................................... 27
4 ) Example: changing the output power of the ETL0470............................................... 28
5 ) Alarm and Warning Thresholds .............................................................................. 29
6 ) Displayed Alarms and Warnings ............................................................................. 29
7 ) Warning LED ......................................................................................................... 30
8 ) Data Communication............................................................................................. 30
IV - ALIGNMENT & MAINTENANCE INSTRUCTIONS .......................................................... 31
1 ) ETL0470 - Changing the channel of operation, simplified procedure........................ 31
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2 ) ETL0480TBD – 1 kW – Replacing one RF Amplifier, simplified procedures................. 32
3 ) ETL0480TBD – 1 kW – Replacing one RF Amplifier, detailed procedure .................... 34
TABLE OF ILLUSTRATIONS
Figure 1: ETL0480TBD-TP Transposer (Exciter + Amplifier).......................................................... 7
Figure 2: UHF TV 700 W RF Power Amplifier Module ETL0470 .................................................... 8
Figure 3: ETL0480TBD TV RF Amplifier blocks diagram............................................................. 11
Figure 4: ETL0470 RF Amplifier blocks diagram........................................................................ 13
Figura 5 A.C. Mains distribution module – rear panel ............................................................... 16
Figure 6: Front panel of ETL0470 TV RF Amplifier Module......................................................... 18
Figure 7: Rear panel of ETL0470 TV RF Amplifier Module.......................................................... 20
Figure 8: Enable socket and connector ..................................................................................... 21
Figure 9: ALARMS OUT socket ................................................................................................. 21
Figure 10: Serial DataRS485 in-out socket............................................................................... 22
Figure 11: Serial Data Com in-out socket ................................................................................. 22
Figure 12: E-LINK SERIAL NETWORK in-out socket.................................................................... 22
Figure 13: Screen of threshold values and calibration data of RF Amplifier ETL0470................... 33
Figure 14: 3 dB hybrid & gain+ phase equaliser MOE142........................................................ 34
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Section A-GENERAL INFORMATION
I - AMENDMENT RECORD SHEET
When an amendment to this publication is incorporated, the record below is to be completed and
initialed.
Release
Language
DESCRIPTION
AUTHORITY
DATE
II - APPROVAL RECORD SHEET
When an approval to this publication is incorporated, the record below is to be completed.
Release
Signature
AUTHORITY
DATE
© EUROTEL S.r.l.
The information contained herein is the property of EUROTEL S.r.l. and is supplied without liability for
errors or omissions and no part may be reproduced, used or disclosed, except as authorized by
contract or other written permission. The copyright and the foregoing restriction on reproduction, use
and disclosure extends to all media in which this information may be embodied, including magnetic or
electronic storage, etc.
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III - WARNINGS
• Observe safety precautions when handling this unit. This equipment operates with dangerous
voltages and currents.
• Always disconnect power before opening covers or removing any part or module of this unit.
•
Prior to checking out or working on the switch mode supply, disconnect all the R.F. power
amplifiers. Some of the R.F. power amplifier transistors are encased in Beryllium Oxide (BeO). This
substance is harmless as is, but becomes very dangerous if ground to a powder. These devices,
once failed, cannot be disposed of by normal means and special procedures of disposal must be
observed.
• In any case, but especially when the RF Power Amplifier is operating, do not attempt to remove
and then re-insert the front panel coaxial interconnecting cables of the EXCITER. Although suitable
protection circuitry is in place, sudden loss and re-application of RF drive causes transients that
may damage one or more RF amplification stages.
• In any case, but especially when the RF Power Amplifier is operating, do not change position of the
switch A.G.C. – m.g.c. in the EXCITER. Although suitable protection circuitry is in place, very high
and sudden variations of RF drive cause transients that may damage one or more RF amplification
stages.
1 ) FIRST AID IN CASE OF ELECTRIC SHOCK
DO NOT TOUCH THE VICTIM WITH YOUR BARE HANDS until the circuit is broken. SWITCH OFF. If
this is not possible, PROTECT YOURSELF with DRY insulating material and pull the victim clear of the
conductor. If breathing has stopped, indicated by unconsciousness, lack of respiratory movements and
a ‘blue’ look to cheeks, lips, ears and nails, START RESUSCITATION AT ONCE.
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2 ) EMERGENCY RESUSCITATION: EXPIRED AIR METHOD
• If possible, lie the victim on his back, with his head slightly higher than his
feet. Clear the mouth and the throat of any obvious obstruction.
• Kneel on one side of the victim, level with his head. LIFT THE JAW AND
TILT THE HEAD BACK AS FAR AS POSSIBLE. (Figures 1a and 1b).
• One of the following may now happen:
⇒ Breathing may begin and consciousness return.
⇒ Breathing may begin, but consciousness may NOT return. Turn the
victim on his side and ensure that the airway is kept clear.
⇒ Breathing may return, but be NOISY, which means that the airway is
not fully clear. Try to clear the airway.
•
IF THERE IS NO SIGN OF BREATHING
⇒ Check that the head is still tilted back.
⇒ Take a deep breath.
⇒ Pinch the victim’s nose and blow firmly into his mouth. As you do, his
chest will RISE (figure 2).
⇒ Turn your head away and take another breath, watching for the chest
to FALL (figure 3).
• Start with four quick deep breaths and then continue with one breath every
five seconds (i.e. 12 times a minute). This should be continued until the
victim revives or a doctor certifies death.
• As consciousness returns, the victim will start to breathe on his own and a
‘pink’ color replaces the ‘blue’ look. This is the time to stop resuscitation.
Continue to hold his chin up and so keep the airway clear.
• In the case of injuries to the mouth, it may be necessary to use mouth-tonose resuscitation. Seal the victim’s mouth with your cheek and blow firmly
into his nose, proceeding as above.
• In any case it is ESSENTIAL to commence resuscitation WITHOUT DELAY and to send for medical
assistance immediately.
3 ) TREATMENT FOR BURNS
If the victim is also suffering from burns, then, without hindrance to resuscitation, observe the following:
•
Do not attempt to remove clothing adhering to the burns.
• If possible, alleviate the pain from the burn part by immersing in cold water.
• If help is available or as soon as resuscitation is no longer required, the wound should be covered
with a DRY clean dressing.
• If help is available or as soon as resuscitation is no longer required, the wound should be covered
with a DRY clean dressing.
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Section B-PURPOSE AND PLANNING INFORMATION
I - INTRODUCTION
•
The ETL0470 TV RF Power Amplifier Module provides linear, class “AB” amplification of composite
Vision+Sound TV signals in the standard UHF bands IV & V (470 to 860 MHz). Rated RF output
power is set to 700 W. Nominal input power is 2 W.
•
This Power Amplifier Module has been expressly designed to be used in combination with others
700 W Amplifiers:
⇒ two power amplifier modules produce an output power in excess of 1kW,
⇒ four power amplifiers modules produce an output power in excess of 2 kW,
⇒ eight power amplifier modules are combined to produce a nominal output power of 5kW.
•
The configuration of two ETL0470 TV RF Power Amplifier Modules is designated model
ETL0480TBD, which comprises two power amplifier modules, two 3 dB hybrids and a band-pass
output filter with a power rating of 1 kW. All these components are housed in a standard 19” metal
cabinet, which provides additional space for the Exciter and for ancillary equipment.
•
A transmitter or a Transposer capable of a full 1 kW output can be built using an Exciter of the
ETL0310 (TV Transmitter) family or of the ETL0290 (TV Transposer) family.
•
A complete selection of options, together with ordering information, is given at the end of this
Section B.
II - SCOPE
•
The scope of this manual is to provide information on the use, operation and maintenance of:
•
The 700 W ETL0470 UHF TV RF Power Amplifier Module.
•
The 1 kW ETL0480TB UHF TV RF Amplifier.
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ETL0480TBD
III - COMPOSITION OF RF AMPLIFIER ETL0480TBD, 1 kW UHF
•
RF Amplifier ETL0480TBD comprises two ETL0470 TV RF Power Amplifier Modules, one input
power divider, one output RF power summer, 50 Ohm balancing load for the hybrid and one
band-pass filter for the attenuation of harmonic and spurious products. All these parts are
assembled into a standard 19” cabinet 1540 mm high (28 Units), which also carries two large
diameter fans for the extraction of hot air. The list of standard parts is as follows.
PARTS SUPPLIED IN THE STANDARD CONFIGURATION
QTY
700 W TV RF Power Amplifiers Modules
Input power divider gain and phase equalizer
3 dB Output power summer
50 Ohm high power balancing load
Output directional coupler
Interconnection cables & accessories kit
Output band pass filter
Air extraction fan
Mains transformer
Standard 28 unit rack cabinet
2
1
1
1
1
1
1
2
1
1
MODEL
ETL0470
MOE142
ETL2140TA
MODM299
ETL2141TA
CAV134
ETL2139TA
VEH4E315
SPT036-1
MECC000343/EURO
Figure 1: ETL0480TBD-TP Transposer (Exciter + Amplifier)
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ETL0480TBD
IV - COMPOSITION OF ETL0470, RF AMPLIFIER MODULE 700 W UHF
•
The ETL0470 TV RF Power Amplifier Module consists of one class “AB” driver stage, that feeds four
class “AB” final RF amplifiers combined. Other parts of this Amplifier are: three identical switch
mode power supply modules, a microprocessor controlled metering, alarm and protection module,
a directional coupler. All these parts are assembled into a standard 4 unit 19 inch rack chassis.
•
The four R.F. amplifiers of the output stage are coupled together by means of three suspended
substrate hybrid couplers.
•
The R.F. amplifier modules are mounted on a massive heat sink in the bottom part of the cabinet
and the 3 switch mode power supplies are mounted at the upper of the cabinet.
•
The modules are:
PARTS SUPPLIED IN THE STANDARD CONFIGURATION
Class “AB” UHF RF buffer Amplifier module
Class “AB” UHF RF Amplifier module (4 final Amplifiers)
Switch Mode Power Supply Unit
Metering, alarm and protection module
QTY
MODEL
1
4
3
1
MOE140-C800
MOE158-B
MOE104ABD
MOE183
Figure 2: UHF TV 700 W RF Power Amplifier Module ETL0470
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V - TECHNICAL SPECIFICATIONS
1 ) General
Primary power
400 V Tri-phase. +10% -15% 50 Hz,
Consumption: 3k W @ 50% A.P.L. at 1 kW vision carrier power.
Cooling
Forced air.
Operating temperature range
-5°C to +45°C.
Storage temperature range
-10 to +70°C.
Nominal UHF output power
1kW
2 ) Input Parameters
Input R.F. nominal level
4 W.
Input impedance
50 Ω, unbalanced.
Input return loss
<18 dB.
3 ) Output Parameters
Output frequency range
BANDS IV-V: 470-860 MHz.
Power gain
> 25dB.
Gain flatness
<1.5 dB.
Output impedance
50 Ω, unbalanced.
Permissible VSWR
<1.5.
Standard Output power
1 kW
Spurious suppression
> 60 dB.
Harmonic suppression
> 60 dB.
Rejection of out of band IMD products
> 60 dB.
I.M.D. Products Suppression
(with driver series ETL0310 or ETL0290)
> 60 dB (-8, -10, -16 dB) @ rated output
power, with pre-correction inserted, system
B/G.
> 60 dB (-6, -10, -17) @ rated output power,
with pre-correction inserted, system I.
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ETL0480TBD
> 60 dB (-6, -13, -17, -20) @ rated output
power, with pre-correction inserted, system I
with Nicam.
4 ) Transmission Quality
(with driver series ETL0310)
Vision weighted S/N ratio (CCIR 567)
> 60 dB.
Amplitude Frequency response
± .5 dB within the Vision band.
Group Delay deviations
± 30 Ns within the Vision band.
2T K factor
< 1.5%.
Luminance non linearity
< 2%.
Differential Gain error
< 3%.
Differential Phase error
< 3°.
Sync pulse compression
< 3%.
Audio frequency S/N ratio
> 64 dB @ 50 KHz deviation.
5 ) Dimensions and Weight
Dimensions
Weight
Page 10
Standard 19” frame, 40 unit.
H=1540mm, D=800mm, L=565mm
120 kg.
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VI - FUNCTIONAL DESCRIPTION
1 ) Theory of operation of 1 kW UHF RF Amplifier ETL0480TBD
•
With reference to the general Blocks diagram, Figure 3, the output signal from the Exciter, at a
nominal level of 4 W, reaches the low power, 3 dB hybrid, which splits the drive into 2 components
of 2 W each. This hybrid incorporates a step attenuator and a step phase shifter to adjust the slight
differences of gain and phase of the two RF Amplifiers. The resultant signals drive the two ETL0470
tandem connected RF Amplifiers to an output level of 600 W each. The 3 dB high power hybrid
connected to the outputs of the two RF Amplifiers sums the output signals to a nominal level of
1kW.
RF output
Enable
commands
RF forward power
Amplifier
ETL0470TAD
“MASTER”
#1
RF
output
Bpass
filter
A.L.C.
EXCITER
(external)
Dir.
Coupler
3 dB Hybrid &
gain+phase
equaliser
50 Ohm
load
50 Ohm
load
3 dB Hybrid
“E”
LINK
Amplifier
ETL0470TAD
“SLAVE”
#2
RF reflected power
Figure 3: ETL0480TBD TV RF Amplifier blocks diagram
•
At the output of the power 3 dB hybrid a directional coupler collects samples of forward & reflected
output power, which are sent to the two ETL0470 RF Amplifiers Modules. Here they are processed
by their internal metering, alarm and protection modules.
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•
Even though the two tandem connected RF Amplifiers are perfectly symmetrical, by convention the
RF Amplifier installed in the upper position in the cabinet is called MAIN AMPLIFIER (or N°1
Amplifier) while the one in the lower position is called the SLAVE AMPLIFIER (or N°2 Amplifier).
•
The Main Amplifier shows, on its multi-function display, in addition to all parameters previously
mentioned, the final (summed) RF forward power output after the pass-band filter. The Slave Amplifier
shows the final (summed) RF reflected power output after the pass-band filter.
•
With reference to the blocks diagram, the Enable and A.L.C. connections are made, and the system
works, as previously described for the single ended ETL0470 RF Amplifier, with the following
differences.
•
During the turn-on phase, the Enable commands go from the Exciter to the Main Amplifier and back.
The Slave Amplifier is enabled through a special interconnection link between the Microprocessors of
the two Amplifiers, which is called E-LINK. The E-LINK has also additional functions, as described
below.
•
The Exciter is driven by the A.L.C. voltage generated by the Main Amplifier only. Therefore the
Exciter closes the loop by producing enough power to drive the Main Amplifier to the power pre-set
by the operator (600 W nominal, in case of 1 kW output). The Slave Amplifier, which has a closely
equalised gain, will “follow” the same drive, to produce an identical output power. This mode of
operation is very simple and is made possible by the close gain & phase balance between the two
Amplifiers, which is an essential design feature of these products. Any slight residual imbalance
(gain and/or phase) can be compensated by adjustments in the drive hybrid.
•
If any protection threshold is reached in only one RF Amplifier the second Amplifier will continue its
work, but in case of excessive RF reflected output power also the second amplifier must be switched
off. This function is obtained through the E-LINK interconnection.
2 ) Theory of operation of 700 W UHF TV RF Amplifier Module ETL0470
•
The ETL0470 UHF TV RF Amplifier Module blocks diagram is shown in figure 4.
•
The nominal RF input of 2 W, coming from the external Exciter, is amplified by the driver module
MOE140C800, to a nominal level of 40 W.
A directional coupler monitors forward input power to the final stage. D.C. samples of these
quantities are sent to the metering, alarm and protection module.
A four way hybrid divider splits the drive power into four components, that feed four modules
MOE158B, each rated at 200 W (nominal) output. RF output from each module is summed by a
four way hybrid combiner.
The output directional coupler, which is equipped with built-in high sensitivity detectors for forward
and reflected RF power, outputs D.C. samples to the Metering and Protection module.
•
The metering, alarm and protection module monitors: the peak and average RF output power, the
peak reflected power and the temperature of the heat sinks. When any one of the pre-set values is
exceeded, the module enters into a warning or into an alarm condition and reduces or disables the
output of the power supplies. When in a disabled alarm condition, the amplifier is automatically
recycled to continuously check the operating status. Once the warning or the alarm condition is
removed, the metering, alarm and protection module returns the power supplies to the normal
operating status.
•
The metering outputs of the metering, alarm and protection module feed an alphanumeric display,
located on the front panel. This display provides all the significant electrical parameters: RF power,
temperature, supply voltages and currents and other important information.
•
The D.C. supply is distributed in such a way that, if one of the power supplies fails, the driver
Amplifier and 3 of the output stages are still supplied. In this condition, the surviving supplies will
sustain an output current increase of several Amperes and the amplifier output will drop to
approximately 25% rated power, but service will not be disrupted.
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ETL0480TBD
•
Should a transistor of one of the RF output stages fail in short circuit, one supply will be shorted out
(the supply will not fail in this condition) and the amplifier output, while dropping, will still be at an
useful level of approximately 25% rated power.
•
Should a transistor of the RF driver stage fail in short circuit, one of the fuses in the driver module
will open, and the amplifier output will drop to approximately 50% rated power.
•
The yellow LINE LED, when lit, shows presence of A.C. power mains.
•
The green ON AIR LED is on when the Amplifier is operating under normal conditions. When the
RF power output drops below approximately half power (- 3 dB threshold), this LED is extinguished.
•
The red ALARM LED is normally dark. It turns on to indicate that one alarm has occurred. In this
condition the Metering, alarm and Protection module immediately disables the amplifier.
•
The red V.S.W.R. ALARM LED is normally dark. It turns on to indicate that the reflected output
power has risen above a pre-set, critical threshold. In this condition the Metering and Protection
module immediately disables the amplifier.
•
The yellow WARNING LED is normally dark. It turns on to indicate that one or more operating
parameters have risen above the normal limiting values. This LED blinks if some past warnings and
alarms are stored in the EEPROM non volatile memory of the microprocessor. This LED turns off
only
RF Amp.
RF Amp.
Driver
Amp.
Four way
Hybrid
divider
Dir.
Coupler
Four way
Hybrid combiner
RF Drive
Amp.(A)
RF
RF
Amp
Logic &
Micro
Digital
display
EXCITER
RF Out
Output
Filter
Dir.
Coupler
Figure 4: ETL0470 RF Amplifier blocks diagram
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VII - RF AMPLIFIER CONFIGURATIONS & ORDERING INFORMATION
The model numbers of all EuroTel RF Amplifiers are based on a 15-position code as follows:
1
2
3
4
5
6
7
8
9
10
11
12
E
T
L
0
4
8
0
T
B
D
See
text
See
text
13
See
text
14
15
Spare
Spare
•
Positions 1 to 3 are fixed and never change.
•
Positions 4 to 7 specify power output and operating class of RF Power Amplifier.
•
Positions 8, 9 and 10 specify RF band of operation. TA is for UHF, Bands IV & V. TAV is for VHF, Band III.
In UHF, position 10 is not used.
•
When the Amplifier is part of a complete Transmitter or Transposer, position 10 in UHF, or 11 in VHF are
used for a separation mark : “ - “, followed, in positions 11 & 12, or 12 & 13 by TX or TP.
•
Positions 14 and 15 are spare.
EXAMPLES:
Description
Single UHF RF Amplifier, 500 W, class “AB”
Code
ETL0470TAD
Single VHF, Band III RF Amplifier, 800 W, class “AB”
ETL0470TAV
Complete TV Transposer, Input UHF, output 1 k W UHF (ETL0290TAS+ETL0480TBD)
ETL0480TBD-TP
Complete TV Transposer, Input VHF, output 500 W UHF (ETL0290TCS+ETL0470TAD)
ETL0470TAD-TP
Complete TV Transmitter, output 1 kW UHF (ETL0310TAS+ETL0480TBD)
ETL0480TBD-TX
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Section C-OPERATING INFORMATION
I - INSTALLATION
1 ) ETL0480TBD R. F. Amplifier: mounting procedure
•
Due to the weight of the components, the 1 kW UHF Amplifier ETL0480TBD is normally shipped in
3 packages, as follows.
⇒ QTY 1 wooden crate, or heavy cardboard container, housing the metal cabinet, which is fully
wired and with all ancillaries, such as 3 dB hybrids, loads, filter, etc. already mounted. This
package has the following approximate dimensions and weight: 1750 x 610 x 940 mm. and
55kg.
⇒ QTY 2 heavy cardboard boxes, housing the ETL0470 RF Amplifiers. Each box has a weight of
approximately 35 kg and dimensions: 680 x 610 x 350 mm.
⇒ A fourth package, can be optionally included, if the Amplifier has been ordered complete with
Exciter. In this case this package consists of a heavy cardboard box, with the following
approximate dimensions and weight: 610 x 570 x 230 mm. and 27 kg.
•
Identify, by means of marking stickers on the RF Amplifiers, the Main Amplifier (marked N°1) and the
Slave Amplifier (marked N°2). For the meaning of these denominations, please see this manual,
Section B, “Functional desciption”. Install N°1 in the upper space in the cabinet and N°2 in the lower
space. These spaces are also marked with corresponding stickers pasted on the inside wall of the
cabinet.
•
Install the Exciter, if supplied, in the space near the bottom of the cabinet.
•
Connect all cables supplied and already wired in the cabinet. In order to simplify this operation,
every cable has stickers at each end. As an additional help, here below is a complete list of all
connections.
QTY 1 “N” to “N” coaxial cable from Exciter, RF OUTPUT socket to low power 3 dB Hybrid.
QTY 2 “N” to “N” coaxial cables from low power 3 dB Hybrid to ETL0470 RF Amplifiers, RF
DRIVE IN sockets.
QTY 2 coaxial cables with 7-16 to 7-16 connectors from ETL0470 RF Amplifiers, RF
OUTPUT sockets, to 3 dB high power hybrid.
QTY 1 “N” to “N” coaxial cable from balancing output of high power 3 dB hybrid, to 50 Ω
high power load.
►
NOTE: the coaxial cable to the antenna must be connected to the free end of the directional coupler
with a 7-16 connector.
QTY 1 BNC to BNC coaxial cable from socket P203 on the rear panel of the Exciter to the
A.L.C. OUT socket of the N°1 RF Amplifier ETL0470.
QTY 1 interconnection cable between the E-LINK sockets of the two RF Amplifiers ETL0470.
QTY 1 coaxial cable (SMA on directional coupler and BNC on Amplifier side) between
FORWARD RF OUT of the directional coupler and the FINAL FWD/REFL.INPUT socket of RF
Amplifier N°1.
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ETL0480TBD
Figura 5 A.C. Mains distribution module – rear panel
•
Prime power line connection:
Connect the ground rod terminal to ground and the R S and T terminal to the three phases.
•
The ETL480TBD RF Amplifier is cooled by forced air stream entering from each front panel
opening of the RF ETL0470 amplifiers. The air is sucked in by one blower installed in the rear of
the rack cabinet. The hot exhaust air is again sucked by another blower installed on the top of the
rack cabinet.
•
The air can be ducted externally by means of flexible, lightweight tubing, with a diameter of 350
mm. The maximum allowable ducting length is 5 meters. With longer runs, a suitable depression
must be created by means of an external fan.
2 ) Other connections
•
Both the ETL0470 make available external alarm connections by means of hard wired and
insulated relay contacts. Additionally, all significant operating parameters are provided on a
standard RS-232 or RS-485 interface.
•
To wire the relay contacts to external circuits, see sub-chapter 10 following and use the ALARMS
OUT socket. Note that contacts are rated 48 V D.C. @ 0.1A maximum.
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3 ) ETL0470: front panel controls, displays & connectors
The front panel of the ETL0470 TV RF AMPLIFIER MODULE is shown in figure 2.
FRONT PANEL
ITEM
DESCRIPTION
SIGNALS AND
CONNECTIONS
R.F. MONITOR
BNC socket to monitor the RF output.
SWITCHES
I O
This switch controls A.C. power to the unit.
PUSH-BUTTONS
SELECT
Controls the menu levels and is menu driven, as
explained in detail in the “MENU DESCRIPTION”
following.
Normally controls the lower row of the display and is
menu driven.
~
DISPLAYS AND LED’s
October 2002
~
Normally controls the upper row of the display and is
menu driven.
PREV.
Controls the menu levels and is menu driven, as
explained in detail in the “MENU DESCRIPTION”
following.
MULTIFUNCTION
METERING DISPLAY
Two row, 16-character alphanumeric display. Shows
levels of: RF output power, supply voltage, supply current
and heats-sink temperature. It also shows warning
conditions, alarm conditions and other information.
LINE LED (YELLOW)
Shows presence of mains voltage.
ON AIR LED (GREEN)
Indicates that the RF Amplifier is operating normally and
RF output is within limits specified.
ALARM LED (RED)
When lit, this LED indicates that one alarm has occurred.
In this condition the Metering, alarm and Protection
module immediately disables the amplifier.
V.S.W.R. ALARM LED
(RED)
As soon as it turns on, the power supply is disabled. This
indicator shows that the reflected RF power alarm has
been triggered.
WARNING LED
(YELLOW)
Indicates one or more warning conditions in act, if
blinking indicates alarm or warning stored in the
EEPROM non-volatile memory.
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Figure 6: Front panel of ETL0470 TV RF Amplifier Module
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4 ) ETL0470: rear panel connectors
The connectors on the rear panel are as follows:
REAR PANEL
ITEM
DESCRIPTION
SIGNALS AND EXTERNAL
CONNECTIONS
R.F. INPUT
R.F. input, type “N” socket. This hole is plugged when
the RF input is installed on the front panel.
R.F. OUTPUT
R.F. output, type “N” or 7/16 socket. This hole is
plugged when the RF output is installed on the front
panel.
ENABLE IN/OUT
Din type socket used to receive the enable voltage from
the Exciter and to send the ready signal to the Exciter.
ALARMS OUT
D type, 25 pin socket. Provides contacts from the
Low Output Power alarm relay and Reflected Power
alarm relay.
E-LINK SERIAL
NETWORK
Type “D”, 9-pin socket, to be connected to the second
amplifier working in tandem configuration.
SERIAL DATA
IN/OUT RS-485
D type 9 pin socket. Sends all amplifier data information
after request from a data gathering external computer.
FINAL FWD/REFL.
INPUT
BNC socket. Auxiliary input to monitor final direct or
reflected power when two twins amplifier work coupled.
A.L.C. OUT
BNC socket for connection of A.L.C. to Exciter.
AC POWER INPUT
Low voltage AC mains socket.
POWER INPUT
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Figure 7: Rear panel of ETL0470 TV RF Amplifier Module
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5 ) Enable IN/OUT DIN socket
3
Socket seen from
back panel of
equipment
1
2
Figure 8: Enable socket and connector
This socket is used:
•
To enable the Amplifier with an external command.
•
To co-ordinate the operation of the RF Amplifier with an external Exciter, by means of an interconnection cable.
•
PIN 1:
+15 V enable to RF Amplifier from external Exciter.
•
PIN 2:
Ground.
•
PIN 3:
+10 V (nominal) enable output (“READY”) signal to external Exciter.
6 ) ALARMS OUT socket
This is a 25 pin DIN type socket, which may be used to make external connections as shown in
following Table.
Table 1: Connections to ALARMS OUT socket
Figure 9: ALARMS OUT socket
PIN
25 PIN DIN SOCKET
1
Low power alarm. Contact closed in alarm condition.
2
Low power alarm. Common contact.
3
Low power alarm. Contact open in alarm condition.
4-5-6-7-8-9-1011-12-13
Not connected.
14
Reflected power alarm. Contact closed in alarm
condition.
15
Reflected power alarm. Common contact.
16
Reflected power alarm. Contact open in alarm
condition.
17-18-19-20-2122-23-24-25
Not connected.
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7 ) SERIAL DATA RS-485 socket
Table 2: Connections to SERIAL DATA RS485 socket
Figure 10: Serial DataRS485 in-out socket
PIN
DESCRIPTION
1
TX Data +
2
TX Data -
3
RX Data -
4
RX Data +
5
Ground.
6
Not connected.
7
Not connected.
8
Not connected.
9
Not connected.
8 ) SERIAL DATA COM (RS-232) socket
Table 3: Connections to SERIAL DATA RS232 socket
Figure 11: Serial Data Com in-out socket
PIN
DESCRIPTION
1
Not connected.
2
TX out
3
RX in
4
RX c.er
5
Ground.
6
Not connected.
7
Not connected.
8
TX c.er
9
Not connected.
9 ) E-LINK SERIAL NETWORK socket
Table 4: Connections to E-LINK SERIAL NETWORK socket
Figure 12: E-LINK SERIAL NETWORK in-out socket
PIN
DESCRIPTION
1
Not connected.
2
CAN low
3
GND
4
Not connected.
5
Shield
6
Not connected.
7
CAN high
8
Not connected.
9
Not connected.
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II - OPERATING PROCEDURES
1 ) First time operation of ETL0480TBD
• Locate the three switches on the front panel of the A.C. Mains Distribution module, near the bottom
of the cabinet. Switch on the mains switch to distribute mains to the cabinet, the three red lamps on
the front panel should turn on, switch on the RF Amplifiers, switch on the Exciter, noise from the fan
should be heard.
•
•
Check that the Multi-function Metering Display is configured as follows.
Amplifier N°1:
⇒ FINAL F/R (upper row): shows the total RF FORWARD output power.
⇒ FWD peak (lower row): shows the total RF FORWARD output of this Amplifier.
•
Amplifier N°2:
⇒ FINAL F/R (upper row): shows the total RF REFLECTED output power.
⇒ FWD peak (lower row): shows the total RF FORWARD output of this Amplifier.
The following procedure must be followed to make sure that the RF cable connections are properly
done:
⇒ Decrease the output power of the exciter by fully rotating counter clock wise the multi-turn
potentiometer (about 15 turns) labelled “Power” on the front panel of the A.G.C. – A.L.C.
Controller plug-in module.
⇒ Turn on the exciter with video modulation signal applied.
⇒ Increase the exciter output power by clock wise rotating the multi-turn potentiometer
labelled “Power” on the front panel of the A.G.C. – A.L.C. Controller plug in module until
reaching about 100W output power on each one of the amplifier modules.
⇒ Check simultaneously that the total forward output power level “”
is about 200W and the total reflected power “FINAL F/R on Amplifier 2” is about 0W.
⇒ If the above values are correct slowly increase the power until reaching 1000W of total
output power, and readjust till reading on Amplifier N.1 an A.L.C. value comprised
between
-5.0% end +5.0% (The A.L.C. control is done on Amplifier N.1).
• If the output RF power is too low to allow control (in this case the green LED “ON AIR” will be off),
the A.L.C. will not start the control.
• The A.L.C. is always best positioned at mid range. To align the A.L.C. voltage, wait at least for half an
hour at full power, to allow the system to reach thermal equilibrium and then locate the “POWER”
screwdriver control on the front panel of the Exciter (A.G.C.-A.L.C. CONTROLLER plug-in). Insert a
small screwdriver and slowly adjust, while looking at the Multi-function Display on the Amplifier 1:
the optimum value is around 0.0%.
•
Remove the vision signal from the Exciter and check that the RF output power drops to 50% or
lower reading. In this condition the LED ON AIR will turn off.
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2 ) RF Amplifier ETL0470: in case of difficulty
•
Absence of RF power from the Amplifier often indicates that the unit is not enabled: in this case
there is no reading at V supply 1, 2 & 3. Also check for presence of vision modulation on drive
signal.
•
A defective Exciter may also be the cause of insufficient or no RF drive. Check Exciter’s output by
using its own RF output meter. Necessary drive power is between 1 and 3 W.
•
If, after turn on, the V.S.W.R. ALARM LED turns on, there is a defective antenna cable or defective
antenna and this problem must be investigated first.
•
If after some time the yellow WARNING LED turns on, this normally indicates that the temperature
of the internal heat sinks is getting too high. Check temperature on the Multi-function Display. Also
check ambient temperature. Remember that at high altitude air density is lower and hence internal
operating temperature is higher. Check for dirty air filters and for defective fans. Sometimes a
defective fans is difficult to find, because it is still turning, but at a lower speed.
•
If, during normal operation, the drive power is removed, with A.L.C. operation enabled, the A.L.C.
loop “freezes” at whatever level it was at the time of removal and operation immediately resumes
as soon as RF drive is re-applied.
•
As soon as the Microprocessor and Protection module detects an alarm condition, as explained in
section B, two items are immediately acted upon: the power supplies are turned off and, at the
same time, the RF drive is turned down, by removing the Enable command to the Exciter. Then the
Amplifier is recycled periodically, to check if the condition causing the alarm has been removed. As
soon as this happens, the RF power output is automatically brought back to normal.
III - ETL0470 - MULTI-FUNCTION METERING DISPLAY
1 ) Alphanumeric LCD display description
Below we list the parameters displayed in an order that is logical and may not correspond to the actual
sequence. The two rows of the alphanumeric LCD display can be indifferently configured to show one of
the following quantities.
Push right button ~: sets the quantity to be displayed in the upper row, which is row 1.
Push left button ~: sets the quantity to be displayed in the lower row, which is row 2.
NOTE : It is advisable to leave the upper row configured to show FORWARD peak RF power and the lower row
configured to show REFLECTED peak RF power.
Vsupply 1 =
32.0 V
Shows the regulated output voltage of the power supply.
Vsupply 2 =
32.0 V
Shows the regulated output voltage of the power supply.
Vsupply 3 =
32.0 V
Shows the regulated output voltage of the power supply.
Isupply 1 =
.... A
Shows the output current of the power supply. ~1A idling.
Isupply 2 =
.....A
Shows the output current of the power supply. ~1A idling.
Isupply 3 =
.....A
Shows the output current of the power supply. ~3A idling.
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Vunreg. =
....V
HS left =
....°C
Shows the temperature of the left side heat sink.
HS right =
....°C
Shows the temperature of the right side heat sink.
FWD drive =
....W
Shows the RF drive level in Watts to the final Amplifier stages.
Shows the rectified, raw voltage D.C. input to the switch mode supply.
From 33 V to 55 V, depending on Mains voltage.
A.L.C. level =
....%
Shows the A.L.C. adjustment range from -24% to +24%. This display
works only if the A.L.C. loop is enabled, as shown in “Menu
descriptions”, below. If the A.L.C. is disabled, this display shows :
“A.L.C. contr. off”. For more information see “first time operation”.
FWD peak =
....W
Shows the forward peak output power of the Vision carrier.
FWD avrg =
....W
Shows the forward average output power of the Vision carrier.
RFL peak =
....W
shows the reflected peak output power of the Vision carrier
RFL avrg =
....W
Shows the reflected average output power of the Vision carrier.
FINAL F/R=
....W
Shows the forward RF final output power on N°1 Amplifier and
reflected final output power on N°2 Amplifier
2 ) Menu Description
To set any particular menu, repeatedly push the SELECT button, until the required menu title appears.
Then the required action is selected pushing one of the two buttons marked with an arrow. Finally the
selected action is memorized by pushing SELECT a second time. Pushing SELECT a third time brings up
the next menu and so on. For more detail see examples in the next pages.
MENU
Display contrast
DESCRIPTION
Changes the alphanumeric LCD display contrast.
Set
Stores the new contrast value.
-
Decreases the display contrast.
+
Increases the display contrast.
View Warning Log
Clear
Shows the last warning conditions which have been stored in “Last in-first out” order. Repeatedly
pushing the buttons, the last 8 warnings are shown, with numbers 0 to 7. “0” is the most recent
warning and “7” is the oldest warning stored.
Clears the non-volatile RAM memory. Displays **Cleared** when actuated.
-
Shows the previous alarm condition.
+
Shows the next alarm condition.
View Alarms Log
Clear
October 2002
Shows the last alarm conditions which have been stored in “Last in-first out” order. Repeatedly
pushing the buttons, the last 8 alarms are shown, with numbers 0 to 7. “0” is the most recent alarm
and “7” is the oldest alarm stored.
Clears the non-volatile RAM memory. Displays **Cleared** when actuated. Note that the yellow
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WARNING LED also turns off when this memory is cleared.
-
Shows the previous warning condition.
+
Shows the next warning condition.
View Work Timer
Shows the working time of the amplifier in hours
TX enable config
Extern Enabled
Amplifier externally enabled. An external signal coming from the Exciter is needed for turn-on.
Always Enabled
Amplifier always enabled. The Amplifier switches on as soon as A.C. power is switched on and the
automatic EEPROM test has been carried out by the internal microprocessor.
ALC ref. power
Store
Changes the reference power of the A.L.C. loop and is used to set the RF power output.
Stores the new reference power level.
-
Decreases the reference power level.
+
Increases the reference power level.
TX A.L.C. config
Enables o disables the A.L.C. loop. When the loop is disabled, the display shows: “A.L.C. contr. off”.
ALC Disabled
The A.L.C. control loop is disabled.
ALC Enabled
The A.L.C. control loop is enabled.
ALC on AUX input
The A.L.C. control loop is enabled, the reference power is referred to the power read on external
aux. Input.
Store LCD View
The measures on the two rows of the display now, will be displayed at power on of the amplifier.
Second level menu
MENU
Vision Frequency
DESCRIPTION
Set approximately the frequency of the Vision carrier at witch the amplifier is working, in order to
provide course correction of the frequency amplitude response of the directional couplers.
Store
Set the new working Vision Frequency.
-
Decreases the working Vision Frequency.
+
Increases the working Vision Frequency.
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3 ) Entering a Menu
The following example shows how to permanently enable the Amplifier.
In the beginning the display is set at the recommended quantities:
Upper row
Lower row
FWD peak =
RFL peak =
600 W
10 W
Push SELECT once, the display will show:
Upper row
Lower row
Push-buttons
FWD peak =
600 W
Menu
row 2 row 1
SELECT
~
~
Push SELECT once again, to enter the menu: the display shows:
Upper row
Lower row→
Push-buttons
Display
Next
SELECT
Contrast
Enter
~
~
Now push SELECT again a few times, until the display shows:
Upper row
Lower row→
Push-buttons
Tx enable config
Next
Enter
SELECT
~
~
Push-button: → to enter this menu:
The display now shows the previously entered ENABLE condition:
Upper row
Lower row→
Push-buttons
Set
SELECT
External
Ext.
Int.
~
~
Push button: → to select the “Internal” (permanent) enable condition. The Amplifier will now be
permanently enabled.
The display shows :
Upper row
Lower row→
Push-buttons
Set
SELECT
Internal
Ext.
Int.
~
~
Now push: SELECT to store the new Tx enable configuration into the memory.
The display shows :
Upper row
Lower row
**
Internal
Stored
**
After several seconds the display will automatically return to the quantities it had been originally
programmed to show:
Upper row
Lower row
October 2002
FWD peak =
RFL peak =
600 W
10 W
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4 ) Example: changing the output power of the ETL0470
• Press the pushbutton SELECT to enter the menu, then push SELECT again several times, until you
reach the menu: A.L.C. Reference Power.
• Set the new reference power by means of the push buttons “+” and “-“, store the new value
and wait until the display automatically exits the menu.
• Check the new amount of A.L.C. control and carefully adjust drive power on the Exciter to get
an A.L.C. reading at or near 0%.
• The following step by step example shows how to change the reference output power from 500
to 450 W.
Set the display to show the following quantities:
Upper row
Lower row
FWD peak =
ALC level =
600 W
3%
Push SELECT to enter the menu; the display shows :
Upper row
Lower row
Push buttons
FWD peak =
600 W
Menu
row 2 row 1
SELECT
~
~
Repeatedly push SELECT, until the display shows:
Upper row
Lower row
Push buttons
Next
SELECT
ALC ref. Power
Exit
Enter
~
~
Push Enter to enter the menu. The display shows :
Upper row
Lower row
Push buttons
ALC ref. Power = 600W
SET
+
SELECT
~
~
Use the push buttons “+” and “-“ to bring the new reference value to 450 W, then push SELECT:
Upper row
Lower row
Push buttons
ALC ref. Power = 550W
SET
+
SELECT
←
→
Wait for a few seconds, until the display automatically reverts to the initial condition:
Upper row
Lower row
FWD peak =
ALC level =
550 W
-10 %
Check the new A.L.C. reading (in this example: –10%) and rotate the screwdriver front panel control
POWER in the Exciter, to obtain a reading of 0.0%, or near this value.
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5 ) Alarm and Warning Thresholds
Forward peak power
~750
W
if the peak output power of the Vision carrier exceeds
this threshold, the power supplies are turned off and
the alarm condition is stored in the EEPROM (nonvolatile memory).
Forward average power
~550
W
if the average output power of the Vision carrier
exceeds this threshold, the power supplies are turned
off and the alarm condition is stored in the EEPROM.
Reflected peak power
40 W
if the reflected peak power of the Vision carrier
exceeds this threshold, the power supplies are turned
off and the alarm condition is stored in the EEPROM.
Input overpower
~40 W
if the peak power of the Vision carrier at the input of
the output stage exceeds this threshold, the power
supplies are turned off and the alarm condition is stored
in the EEPROM (non volatile memory).
Heat-Sink
Warning Temperature
63 °C
if one of the heat-sinks exceeds this threshold, the
power supply voltages are lowered and the warning
condition is stored in the EEPROM.
Heat-Sink
Alarm Temperature
70 °C
if one of the heat-inks exceeds this threshold, the
power supplies are turned off and the alarm condition is
stored in the EEPROM.
NOTE: When a temperature alarm occurs, TWO conditions are naturally always stored in the EEPROM,
one is for the temperature warning (temperature reaches 63 °C), that was stored while the temperature
was rising and the other is the temperature alarm itself (temperature reaches 70 °C).
6 ) Displayed Alarms and Warnings
When an alarm or warning condition is detected, the lower row of the display shows the following:
DISPLAY
ALARM and WARNING DESCRIPTION
V.S.W.R alarm
The output reflected power exceeded the alarm threshold (the
V.S.W.R. alarm LED is lit).
peak overpw. alrm
The peak output power exceeded the alarm threshold.
avrg. overpw. alrm
The average output power exceeded the alarm threshold.
heat sink warning
The temperature of one or both heat sinks exceeds the warning
threshold and voltage has been automatically shifted down.
heat sink temp hi
The temperature of one or both heat sinks exceeds the alarm
threshold, the ALARM LED is lit and the power supplies have been
switched off.
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ETL0480TBD
7 ) Warning LED
When lit, this yellow LED indicates that one ore more warning conditions are present, as shown on the
upper row of the display, if blinking indicates that a warning or alarm condition had been stored in the
EEPROM non volatile memory.
To clear this LED the alarm and warning memories have to be cleared. This can be done only during
normal operation and when no warning or alarm conditions exist. To clear the memories, proceed as
follows.
•
Repeatedly push the SELECT button, until “View warning log.” appears.
•
Push button → to enter this menu.
•
Push CLR. The display will show: “** Cleared **”.
•
Then repeatedly push the SELECT button, until “View alarms log.” appears.
•
Push button → to enter this menu.
•
Push CLR. The display will show “** Cleared **”. At this point the yellow WARNING LED will go
off.
8 ) Data Communication
•
A serial CAN port E-LINK network interconnection among power amplifiers.
•
A serial port is available as output interface in RS-232 standard.
•
A serial port is available as output interface in RS-485 standard.
•
The Technical information manual for the installation and operation of the interface is available
from EuroTel to EuroTel Customers on request.
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IV - ALIGNMENT & MAINTENANCE INSTRUCTIONS
1 ) ETL0470 - Changing the channel of operation, simplified procedure
To change the channel of operation, two procedures must be followed.
•
The output filter (if installed) must be re-aligned on the new frequency. A detailed procedure is
available in section D, technical information.
•
The calibration of the internal power sampling directional couplers must be changed, as outlined
below.
When changing the channel of operation of the ETL0470, it is necessary to change the calibration of
the internal power sampling directional couplers. Calibration data is stored in 100 MHz intervals in the
memory of the resident Microprocessor and is changed by following this step by step procedure.
IMPORTANT: The menu entries from V.unreg, as described below, are only available on Equipment with Serial
Number: 9314 or higher. For older equipment, please contact the factory.
⇒ Set upper and lower positions of the front panel meter to Vunreg.
⇒ Push “SELECT” several times, until “Frequency band” appears.
⇒ Push “Enter”, to enter this menu. You will see the frequency band at which the Amplifier had
previously been set up.
⇒ On the “+” and “-“ push-buttons, the entire UHF band is available, in steps of 100 MHz.
⇒ Now using “+” or “-“ set the frequency nearest to the new operating channel which must be
used.
⇒ EXAMPLE: suppose original channel is 28 B/G (Vision frequency 527.25 MHz) and the new
channel is 58 B/G (Vision frequency 767.25). You would find the original step as : 550-650
[MHz]. Now push “+” until you see: 750-800 [MHz].
⇒ Now push: “Set”, to store the new setting. The word “Stored” will appear on the display.
⇒ After a few seconds the system will automatically revert to normal operating status.
WARNING: If the Amplifier is operated at a different channel without executing this calibration procedure, all the
internal RF power readings will be out of calibration and therefore the front panel wattmeter readings, the alarm
thresholds and the protection thresholds will be out of calibration.
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2 ) ETL0480TBD – 1 kW – Replacing one RF Amplifier, simplified procedures
Due to the reliability of the basic ETL0470, partial failures in one RF Amplifier are very rare and total
failures, due to the 3X architecture, extremely unlikely. When a partial failure in one 700 W RF
Amplifier is detected, there are two possible courses of conduct.
•
Remove the defective Amplifier for repairs and run the Transmitter with one Amplifier only. In this
case:
⇒ Remove the 3 dB power splitter at the output of the Exciter and also the 3 dB hybrid at the
summing output.
⇒ Connect the output of the Exciter directly to the input of the RF Amplifier.
⇒ Connect the output of the RF Amplifier directly to the input of the band-pass RF output filter.
⇒ Repeat the first time operation procedure, as directed for the single ended ETL0470 RF
Amplifier. This procedure is necessary to properly adjust the drive level for rated output and to
properly calibrate the A.L.C. circuitry.
•
Remove the defective Amplifier for repairs and install a spare Amplifier. In this case:
⇒ Make sure the spare ETL0470 RF Amplifier is set at the wanted operating band. When in
doubt, follow the procedure for calibrating the internal RF samplers, as shown in the previous
page.
⇒ Install the spare RF Amplifier and make all connections. Installation procedure shown in
Chapter I, “INSTALLATION”, above may be of help, when in doubt.
⇒
IMPORTANT: The menu entries from V.unreg, as described below, are only available on Equipment
with Serial Number: 9314 or higher. For older equipment, please contact the factory.
⇒
CALIBRATION OF FINAL RF POWER READINGS: In the ETL0480TBD the final readings of Forward
and Reflected RF power at 1 kW level are performed by the RF Amplifiers. If one RF Amplifier is
replaced, then the calibration factor of that Amplifier must be set, to take into account the
calibration of the external RF coupler.
⇒ In the performance data booklet delivered with each Amplifier, in section PQ: “Final
performance data” we give a screen showing all calibration settings of the Amplifier, as shown
in figure 13. Under the heading: “Coupler Adjust”, read: FWD out=xx% and note number xx,
which is the coupler calibration factor. If the booklet is not available, you can obtain the
calibration factor from the Amplifier that has been replaced, or from the Amplifier still in
operation, as explained in the “Detailed procedures” below.
Page 32
➘
Set upper and lower positions of the front panel meter of the replacement Amplifier to:
Vunreg.
➘
Now push SELECTseveral times until you reach: Aux. coupler adj. Push Enter. You will
now see on the meter: Aux=ddd W. Adj xx. Where the number “ddd” is the RF power
output reading and “xx” is the calibration factor. Number xx can have any value
between –50 and +50 [%].
➘
Disregard “ddd”. Now push buttons “+” or “-“ to insert the same value of the
calibration factor xx.
➘
Now push Set. The meter in the F/R position of Amplifier #2 is now calibrated and
normal operation can be resumed.
CMAN0480ENG
October 2002
EUROTEL - ITALY
ETL0480TBD
Figure 13: Screen of threshold values and calibration data of RF Amplifier ETL0470
The external coupler calibration factor
xx is available in this window
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ETL0480TBD
3 ) ETL0480TBD – 1 kW – Replacing one RF Amplifier, detailed procedure
⇒ Make sure the spare ETL0470 RF Amplifier is set at the wanted operating band. When in
doubt, follow the procedure for calibrating the internal RF samplers, above.
⇒ Install the spare RF Amplifier and make all connections. Installation procedure shown in
Chapter I, “INSTALLATION”, above may be of help, when in doubt.
⇒ Identify the 3 dB hybrid & gain+phase equaliser, MOE142. This device is the 3 dB splitter of
the RF drive from the Exciter to the two RF Amplifiers. Remove the 10 screws holding the cover
lid in place.
Input
Load
3 dB hybrid
A
0.125
dB
A
0.125
dB
A
0.25 dB
Phase
∅ 20°
A
0.5dB
Phase
∅ 10°
A
1 dB
A
1 dB
Phase
∅ 2.5
Phase
∅ 2.5°
Phase
∅ 5°
Phase
∅5°
A
0.5 dB
A
0.25 dB
Phase
∅ 10°
Phase
∅ 20°
Output 2
Output 1
Figure 14: 3 dB hybrid & gain+ phase equaliser MOE142
⇒ Each output of the internal 3 dB hybrid is equipped with 4 attenuators in series and with 4
phase shifting lines is series. Attenuators are in values 1-2-4-8, starting with 0.125 dB. Phase
shifting lines are also in values 1-2-4-8, starting with a nominal phase value of 2.5°.
⇒ Attenuators and lines can be inserted or removed from the circuit by soldering in or out special
chip type shorts: these shorts look like chip resistors, but they are imprinted with “000”.
NOTE: The procedure that follows must be executed with a reduced, non-modulated vision carrier only.
With Equipment turned off, witch sound carrier off. Remove video modulation and turn scredriver
control “POWER” on the A.G.C.-A.L.C. Controller front panel fully counterclockwise.
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ETL0480TBD
⇒ POWER BALANCING: Turn equipment on and slowly turn POWER screwdriver control to read
approx. 200 W RF output on each RF Amplifier meter (lower scale). You will note that one
Amplifier will give slightly more power then the other. Calculate the difference in power in dB
and then adjust then increase the value of the attenuator of this Amplifier, or decrease the
value of the other Amplifier of the same value.
⇒ EXAMPLE: After having replaced one amplifier, the reading on Amplifier #1 is 195 W and the
reading on Amplifier #2 is 215 W. The difference is 20 W, or approx. 0.4 dB. Supposing that
no attenuation is inserted on Amplifier #1, insert the 0.25 dB and the 0.125 dB attenuators
(total 0.375 dB) on the drive of Amplifier # 2. You will now have a reading of 195 W on
Amplifier #1 and 200 W on Amplifier #2, with a difference of 5 W or less.
⇒ PHASE BALANCING: Switch equipment off. Locate the 50 Ohm output balancing load, connected to
the balance port of the output 3 dB coupler. Insert a Thruline (or equivalent) wattmeter between
the 3 dB coupler and the load. Turn equipment on and note reading on wattmeter. If reading is
2% or less of output power (e.g. up to 4 W in the previous example), no action should be
undertaken.
⇒
The power flowing into the balancing load is due to phase imbalance and can be reduced to
near zero by adjusting the phase. To see which Amplifier has the more phase shift, slowly and
carefully, PARTIALLY unscrew one of the two “N” connectors of the cable from the drive hybrid
(MOE142) in order to achieve a longer path, BUT WITHOUT INTERRUPTING THE CONTACT. If the
power into the balance load increases, less phase shift is needed on this side, or more in the
other side.
⇒
Once the side that needs more phase shift is found, tighten the “N” connector and insert more
phase shift on that side, in nominal steps of 2.5°, until an imbalance of 2% or less of the output
power, as read in the F/R position of Amplifier #1, is reached. Remove the wattmeter reading
the imbalance power.
⇒
IMPORTANT: The menu entries from V.unreg, as described below, are only available on Equipment
with Serial Number: 9314 or higher. For older equipment, please contact the factory.
⇒
CALIBRATION OF FINAL RF POWER READINGS: In the ETL0480TBD the final readings of Forward
and Reflected RF power at 1 kW level are performed by the RF Amplifiers. If one RF Amplifier is
replaced, then the calibration factor of that Amplifier must be set.
⇒
Insert a reference wattmeter between main output of Transmitter and antenna (or dummy
load). Turn Transmitter on, again with a reduced, non-modulated vision carrier only, to read an
output of approx. 500 W on the external reference wattmeter.
⇒
If Amplifier #1 has to be replaced.
➘
Check total (1 kW) RF output reading on Amplifier #1. If the reading is out of
calibration by 5%, or more, set upper and lower positions of the front panel meter to:
Vunreg.
➘
Now push SELECT several times until you reach: Aux. coupler adj. Push Enter. You will
now see on the meter: Aux=ddd W. Adj xx. Where the number “ddd” is the RF power
output reading and “xx” is the calibration factor.
➘
Now push buttons “+” or “-“ to calibrate the reading on the front panel meter to
within ± 5% of the external reference wattmeter.
➘
Now push Set. The meter in the F/R position of Amplifier #1 is now calibrated.
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⇒
ETL0480TBD
If Amplifier #2 has to be replaced.
➘
The original calibration factor can be obtained from the performance data booklet
delivered with each Amplifier. If the booklet is not available, the calibration factor can be
recovered from the failed Amplifier or from the Amplifier still operational, using the
procedure that follows.
➘
set upper and lower positions of the front panel meter of the Amplifier to: Vunreg.
➘
Now push SELECT of the Amplifier several times until you reach: Aux. coupler adj. Push
Enter. You will now see on the meter: Aux=ddd W. Adj xx. Where the number “ddd” is
the RF power output reading and “xx” is the calibration factor.
➘
Write down the value of this calibration factor xx, which can be a number between –
50 and +50 [%].
➘
Now push SELECT of replacement Amplifier, several times until you reach: Aux. coupler
adj. Push Enter. You will now see on the meter: Aux=ddd W. Adj xx. Where the number
“ddd” is the RF power output reading and “xx” is the calibration factor.
➘
Disregard “ddd”. Now push buttons “+” or “-“ to insert the same value of the
calibration factor xx, as read on Amplifier #1.
➘
Now push Set. The meter in the F/R position of Amplifier #2 is now calibrated.
⇒ Follow the first time operation procedure, as described in Chapter I, “INSTALLATION”, to
properly set up the A.L.C. circuitry.
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October 2002
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