LPA–2
50/100W LINEAR POWER AMPLIFIER
System Manual
CA44–VER06
ameTeK Power instruments
4050 n.W. 121st avenue
Coral Springs, Fl 33065
1–800–785–7274
+1-954-344-9822
www.ametekpower.com
The BrighT STar in UTiliTy CommUniCaTionS
February 2018
Ordering Information
Product Description
Applications
Installation
LPA-2
System Manual
Table
of
Contents
Test Equipment
Adjustment
Maintenance
1
2
3
4
5
6
7
ESD Warning!
YOU MUST BE PROPERLY GROUNDED, TO PREVENT DAMAGE FROM
STATIC ELECTRICITY, BEFORE HANDLING ANY AND ALL MODULES OR
EQUIPMENT FROM AMETEK.
All semiconductor components can be damaged by the discharge of static electricity.
Be sure to observe all Electrostatic Discharge (ESD) precautions when handling
modules or individual components.
!
IMPORTANT
We recommend that you become acquainted with the information in this manual before energizing your power amplifier. Failure to do so may result in injury to personnel or damage to the
equipment, and may affect the equipment warranty. If you mount the carrier unit in a cabinet,
it must be bolted to the floor or otherwise secured before you swing out the equipment, to
prevent the installation from tipping over.
You should not remove or insert printed circuit modules while the power amplifier is energized.
Failure to observe this precaution can result in undesired tripping output and can cause
component damage.
AMETEK does not assume liability arising out of the application or use of any product or circuit
described herein. AMETEK reserves the right to make changes to any products herein to
improve reliability, function or design. Specifications and information herein are subject to
change without notice. All possible contingencies which may arise during installation,
operation, or maintenance, and all details and variations of this equipment do not purport to be
covered by these instructions. If you desire further information regarding a particular installation, operation, or maintenance of equipment, please contact your local
AMETEKrepresentative.
Copyright © AMETEK
ALL RIGHTS RESERVED
AMETEK does not convey any license under its patent rights nor the rights of others.
ii
February 2018
linear Power amplifier lPa–2
Preface
Scope
This manual describes the functions and features of the LPA-2. It is intended primarily for use by engineers
and technicians involved in the specification, application, operation, and maintenance of the LPA-2.
Equipment Identification
The equipment is identified by the Catalog Number on the front of the chassis.
Warranty
Our standard warranty extends for 5 years after shipment. For all repaired modules or advance replacements, the standard warranty is 1 year or the remaining warranty time, whichever is longer. Damage clearly
caused by improper application, repair, or handling of the equipment will void the warranty.
Equipment Return & Repair Procedure
To return equipment for repair or replacement:
1. Call your AMETEK representative at 1–800–785–7274 (or 954-344-9822) or e-mail at
repair.pulsar@ametek.com.
2. Request an RMA number for proper authorization and credit.
3. Carefully pack the equipment you are returning.
Repair work is done most effectively at the factory. When returning any equipment, pack it in the
original shipping containers if possible. Be sure to use anti-static material when packing the
equipment. Any damage due to improperly packed items will be charged to the customer, even
when under warranty.
AMETEK also makes available interchangeable parts to customers who are equipped to do repair
work. When ordering parts (components, modules, etc.), always give the complete AMETEK part
umber(s).
4. Make sure you include your return address and the RMA number on the package.
5. Ship the package(s) to:
AMETEK Power Instruments
Pulsar Products
4050 NW 121st Avenue
Coral Springs, FL USA 33065
February 2018
iii
Table of Contents
Topic
Chapter 1. Ordering Information
Ordering Information . . . . . . . . . . . . . . . . . . . . . . . .
Chapter 2. Product Description
2.1 General Description . . . . . . . . . . . . . . . . . . . . . .
2.2 Standard Nomenclature . . . . . . . . . . . . . . . . . . .
2.3 50 W / 100 W LPA-2 Chassis . . . . . . . . . . . . . . .
2.3.1 Front Panel Tour . . . . . . . . . . . . . . . . . . . .
2.3.2 Rear Panel Tour . . . . . . . . . . . . . . . . . . . . .
2.4 50 W / 100 W Options . . . . . . . . . . . . . . . . . . . .
2.5 50 W / 100 W Configurations . . . . . . . . . . . . . . .
2.5.1 50 W Configuration . . . . . . . . . . . . . . . . . .
2.5.2 100 W Configuration . . . . . . . . . . . . . . . . . .
2.6 Specifications . . . . . . . . . . . . . . . . . . . . . . . . . .
2.7 Environmental Requirements . . . . . . . . . . . . . . .
2.8 Power Requirements and Dimensions . . . . . . . . .
Chapter 3. Applications
3.1 50 W / 100 W Applications . . . . . . . . . . . . . . . . .
3.1.1 Directional Comparison Blocking Systems .
3.1.2 Phase Comparison Blocking . . . . . . . . . . . .
3.1.3 Systems Using FSK . . . . . . . . . . . . . . . . . .
Chapter 4. Installation
4.1 Installing Your New LPA–2 . . . . . . . . . . . . . . . .
4.1.1 Unpacking & Inspecting . . . . . . . . . . . . . . .
4.1.2 Mounting . . . . . . . . . . . . . . . . . . . . . . . . . .
4.1.3 Connecting to the Rear Panel . . . . . . . . . . .
Chapter 5. Test Equipment
Test Equipment . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Chapter 6. Adjustment
6.1 General Adjustment Information . . . . . . . . . . . . .
6.2 50 W Adjustment Procedure . . . . . . . . . . . . . . .
6.3 100 W Adjustment Procedure . . . . . . . . . . . . . . .
6.3.1 100 W Adjustment (as shipped from factory)
6.3.2 100 W Custom Adjustment . . . . . . . . . . . . .
Chapter 7. Maintenance / Troubleshooting
7.1 Periodic Checks . . . . . . . . . . . . . . . . . . . . . . . . .
7.2 Troubleshooting Sequence . . . . . . . . . . . . . . . . .
iv
Page No.
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.2–1
.2–1
.2–1
.2–3
.2–3
.2–4
.2–4
.2–4
.2–4
.2–4
.2–7
.2–9
.3–1
.3–1
.3–2
.3–2
.4–1
.4–1
.4–1
.4–2
. . . . . . . . . . . . . . . . .5–1
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.6–1
.6–2
.6–4
.6–4
.6–5
. . . . . . . . . . . . . . . . .7–1
. . . . . . . . . . . . . . . . .7–1
February 2018
Chapter 1. Ordering Information
Ordering Information
The 50 W LPA-2/100 W LPA-2 equipment identification number (catalog number) is located on the front
of the chassis. The catalog number comprises nine (9) characters, each in a specific position. This number
tells you whether the LPA-2 is a standalone 50 W chassis or one of the two chassis for a 100 W unit.
The table below provides a complete listing of the options for ordering a 50 W or 100 W unit, as well as
a sample catalog number. To order a 50 W LPA-2 or 100 W LPA-2 assembly, simply identify the output
power, DC voltage supply and options you want for each assembly. For example, the typical catalog
number shown —L P A 2 1 0 0 1 B — orders a complete 100 W unit with a 125/250 Vdc power
supply and a built-in skewed hybrid, comprised of two chassis.
Table 1–1. lPa–2 Catalog numbers.
Catalog Number Position
Typical Catalog Number
Basic Unit
LPA–2
Linear Power Amplifier
Output Power
050
50 Watts
100
100 Watts
DC Supply Voltage
4
48 Vdc
125/250 Vdc
1
None 1
N
100 W Combiner 2
C
Options
Skewed Hybrid 1
S
Both 100 W Combiner & Skewed Hybrid 2
1 Only
2 Only
applies to 50W units (LPA2050xx).
used for 100W units (LPA2100xx).
Copyright © ameTeK
B
1 2 3 4
L P A 2
5 6 7
1 0 0
8
1
9
B
1
linear Power amplifier lPa–2 System manual
In addition to the catalog number, identifying a complete 50 W LPA-2/100 W LPA-2 assembly,
a listing of spare parts is provided below.
Table 1–2. 50 W / 10 0W lPa-2 Spare Parts.
Part Type
Module
Module
Module
Dummy Load
Coax Cable
Coax Cable
Coax Cable
Description
Option Board with 100 W Combiner & Skewed CA20-PA5A2-001
Hybrid
Option Board – Skewed Hybrid Only
CA20-PA5A2-002
Option Board – 100 W Combiner Only
CA20-PA5A2-003
50 Ω, 100 W Short-Term Load
CA20-PA5A3-001
5 ft. Long BNC–BNC
01W1-COAX5-111
1.5 ft. Long BNC–BNC
12 ft. Long BNC–BNC
Terminal Block 5-Position Plug-In Type
Fuse (F1)
Fuse (F1)
Coax T
Page 1–2
Part Number
Fast-Blow 3 A, 3AG Type for 125 / 250 Vac
Fast-Blow 10 A, 3AG Type for 48 / 60 Vdc
Y-Connector (1 Male BNC to 2 Female BNC)
01W1-COAX2-111
01W1-COAXA-111
01NR-FXP05-340
01RM-FEM31-000
01RM-FIM31-000
01NC-BNCY1-000
February 2018
Chapter 2. Product Description
2.1 General Description
The AMETEK Linear Power Amplifier (LPA-2) comes in two versions:
1) The 50 W LPA-2 (a single chassis with a 50 W output)
2) The 100 W LPA-2 (two 50 W chassis combined for a 100 W output)
Both are class AB amplifiers that put out their rated power of 50 and 100 W continuously over a frequency
range of 30–535 kHz. Both units are designed for inserting between an existing power-line carrier unit and
the line tuner (LMU) to boost the normal power output of the carrier system.
The LPA-2 has the following important features.
• Automatic overload protection on its signal input and output.
• Self monitoring alarm.
• Built-in 50 Ω short-term 100 W load for testing.
• Optional built-in skewed hybrid.
Functional block diagrams and board layouts for the Main Amplifier, Overload Protection/Alarming and
DC Power Supply are at the end of this chapter.
2.2 Standard Nomenclature
The standard nomenclature for AMETEK’s linear power amplifier equipment is as follows:
Cabinet – contains fixed-racks, swing-racks, or open racks
Rack – contains one or more chassis
Chassis – contains several printed circuit boards, called modules (e.g., Power Supply or Power
Amplifier)
Module – contains a number of functional circuits
Circuit – a complete function on a printed circuit board
2.3 50 W / 100 W LPA-2 Chassis
All individual chassis have the following standard dimensions:
Height – 3.50” (88.9 mm), requiring 2 rack units
Width – 19.00” (482.6 mm)
Depth – 14.63” (371.6 mm)
Each chassis has standard mounting holes for installation in a standard relay rack. And the chassis can be
mounted either flush or projected by moving the mounting brackets to alternate side-plate positions.
Copyright © ameTeK
2
linear Power amplifier lPa–2 System manual
Front Panel
CATALOG# LPA21001C
CHASSIS 1 OF 2
DC INPUT: 125/250VDC
12
11
1
2
3
4
5
6
7
8
9
10
Figure 2–1a. Front View.
8
Rear Panel
6
11
1
2
3
4
5
7
9
10
Figure 2–1b. rear View.
Page 2–2
February 2018
Chapter 2 Product Description
2.3.1 Front Panel Tour
The LPA-2 front panel has a user-friendly power
level adjustment, LEDs, & test points. The
function of each item is detailed below (displayed
left to right in Fig. 2–1a).
1. “AMP OK” Green LED – Self-monitoring
hardware LED. When illuminated, it
indicates that the unit’s power supply and
amplifier are both working. Compares
output power against input power to
confirm amplification when signal is
applied. When this LED turns off the LPA2 alarm relay de-energizes and the alarming
contact changes state.
2. “OVERLOAD” Red LED – Flashes on/off
when too much input signal is applied, the
load impedance is too far from 50 Ω, or any
other condition that would cause overheating.
3. “LEVEL ADJUST” Pot – Adjusts input
level drive to correct level for 50 W output.
Clockwise rotation increases level.
4. “100W NULL” Test Point – Connected
across optional 100W combiner balance
resistor. Only used when combining two
50W units to balance a 100W output. When
the signal level is nulled, on this test point,
the units are set for optimum performance
with low power loss in the combiner.
5. “AMP IN” Test Point – Amplifier input
signal coming from driving Transmitter.
6. “COMMON” Test Points (2 available) –
The common for all other front panel test
points.
7. “OUT” Test Point – The output of the
amplifier.
8. “Push to Open” Pushbutton Switch – In
series with the output of the amplifier
before going to the line. Allows an in-line
meter to be inserted between the amplifier
OUTPUT and the LINE test points for
measuring forward or reflected power.
9. “LINE” Test Point – The final output of the
amplifier going to the LINE coax
connector on the back.
February 2018
10. “HYBRID RX” Test Point – When
ordered with the skewed hybrid option this
allows measuring the signal level, at hybrid
RX port, going to the Receiver.
11. Serial # Label – Barcoded. Center 4 digits,
separated by spaces, are YYWW
(YY= 2 digit year, WW= 2 digit week).
12. Catalog # Label – Shows the 9-digit
catalog #, Chassis ID (when part of a 100
W unit), and DC voltage input.
2.3.2 Rear Panel Tour
The LPA-2 rear panel has connections, a fuse, and
an on/off switch. The function of each item is
detailed below (left to right, top to bottom Fig. 2–
1b).
1. Ground Stud (#6-32) – Chassis ground.
Connect with a # 10 gauge or larger wire
directly to the ground bar in the panel/rack.
2. “ALARM” On 5-Position Terminal Block
– Self-monitoring alarm normally closed
contact (terminals 4 & 5) or normally open
contact (terminals 4 & 3) available. This
alarm relay is energized when the LPA-2 is
working and will de-energize if there is an
alarm condition or a power failure.
3. “DC IN” On 5-Position Terminal Block –
Polarity sensitive dc power input (terminal
1 is positive & 2 is negative).
4. “FUSE (F1)” – For dc power input.
Removable with a screwdriver if blown.
DC Volt Input
48 V
125/250 V
F1 Value
Fast-Blow 10 A Fast-Blow 3 A
5. “HYBRID RX (J9)” – When ordered with
the skewed hybrid option, this connects to
the Receiver, otherwise unused.
6. “SHORT-TERM 50 Ω LOAD” – This is a
50Ω dummy load resistor temporarily
connected, with an external coax cable, to
the LINE (J5) connector only during the
adjustment/checking, of the transmit signal
level.
Page 2–3
2
linear Power amplifier lPa–2 System manual
7. “LINE” (J5) – Connects amplifier output to
the line tuner (LMU).
8. “50W IN (J7) – Only used for 100 W units
when combining the 50 W output from
another chassis with this unit to get 100 W
total power.
9. “AMP IN (J6)” – Connects amplifier input
to a driving carrier unit.
10. “DC POWER” On/Off Slide Switch –
Turns dc power on and off. Recessed to
prevent accidental powering up or down.
Power off with a small screwdriver before
disconnecting any wires.
11. Voltage/Chassis ID Label – located on the
heat sink perpendicular to the rear panel.
Indicates Catalog #, Chassis ID (1 or 2 of
2) & DC Input.
2.4 50 W / 100 W Options
As shown in Chapter 1 (Ordering Information), a
built-in skewed hybrid is available for the LPA-2.
Also, the correct DC input voltage must be
chosen.
2.5.1 50 W Configuration
The 50 W LPA-2 comprises one chassis assembly,
coax cables and an optional skewed hybrid.
2.5.2 100 W Configuration
The 100 W LPA-2 comprises two chassis assemblies with coax cables as follows:
• Chassis #1 (1 of 2) – Master unit that is a
basic 50 W amplifer plus a 100 W
combiner module and an optional skewed
hybrid.
• Chassis #2 (2 of 2) – Slave unit that is just
a basic 50 W amplifier.
2.6 Specifications
The LPA-2 meets or exceeds all applicable
ANSI/IEEE standards. Table 2-1a/b shows the
technical specifications for the 50 W version. The
technical specifications for the 100 W LPA-2 are
shown in Table 2-2a/b.
2.5 50 W / 100 W Configurations
The AMETEK Linear Power Amplifier (LPA-2)
comes in two configurations:
1) The 50 W LPA-2 (one chassis with a 50 W
output)
2) The 100 W LPA-2 (two chassis with a
combined 100 W output)
Page 2–4
February 2018
Chapter 2 Product Description
Table 2–1a. 50 W lPa-2 Technical Specifications.
Frequency Bandwidth
30 kHz–535 kHz
Output Impedance
50 Ω
Input Impedance
2
Settable 50 Ω (normal setting) or 5 kΩ
Maximum RF Power Input
Recommended RF Power Input
Minimum RF Power Input
(to get 50 W output)
Maximum Power Output
Harmonic & Spurious Noise Output
Alarm Relay Contact Rating
50Ω Dummy Load (Testing & Setup)
Standard Compliance
10 W (+40 dBm or 22.4 V, 50 Ω reference)
5 W (+37 dBm or 15.8 V, 50 Ω reference)
2 W (+33 dBm or 10V, 50 Ω reference)
50 W continuous single frequency into 50 Ω load
(+47 dBm, 50 Ω reference)
50 dB below 50 W fundamental
15 ms max operate time, 1 A max make/carry, 0.25 A
max interrupt at 250 Vdc
80 W Continuous, 100 W for 2 Minutes
Meets relevant specifications: IEEE C93.5
1
1 Unless otherwise shown in the specification tables.
Table 2–1b. optional Skewed hybrid Specifications.
Specification
Frequency Range
30–535 kHz
TX Port Impedance (Internal)
50 Ω
Max Power TX Input
100 W
RX Port Impedance (J9)
50 Ω or High Z (Open)
Insertion Loss: TX Port to Output*
0.5 dB Max
Output Port Impedance (J5)
Insertion Loss: Output to RX Port * (J5–J9)
Transhybrid Loss: Isolation Between TX & RX*
* With Exact Impedance Matching on Output
February 2018
Value
50 Ω
14.5 dB Max
40 dB Min
Page 2–5
linear Power amplifier lPa–2 System manual
Table 2–2a. 100 W lPa-2 Technical Specifications.
Frequency Bandwidth
30 kHz–535 kHz
Output Impedance
50 Ω
Input Impedance
Settable to 50 Ω or 5 k Ω. (Normally one 50 W chassis is
set to 50 Ω and the other to 5 k Ω.)
Maximum RF Power Input
Recommended RF Power Input
Minimum RF Power Input
(to get 100W output)
Maximum Power Output
Harmonic & Spurious Noise Output
Maximum Overall Power Loss for
Failure of one 50 W Power Amplifier:
Alarm Relay Contact Rating
50Ω Dummy Load (Testing & Setup)
Standard Compliance
10 W (+40 dBm or 22.4 V, 50 Ω reference)
5 W (+37 dBm or 15.8 V, 50 Ω reference)
2 W (+33 dBm or 10V, 50 Ω reference)
100 W continuous single frequency into 50 Ω load
(+50 dBm, 50 Ω reference)
50 dB below 100 W
–3.5 dB
15 ms max operate time, 1 A max make/carry, 0.25 A
max interrupt at 250 Vdc
80 W Continuous, 100 W for 2 Minutes
Meets relevant specifications: IEEE C93.5
1
1 Unless otherwise shown in the specification tables.
Table 2–2b. optional Skewed hybrid Specifications.
Specification
Frequency Range
30–535 kHz
TX Port Impedance (Internal)
50 Ω
Max Power TX Input
100 W
RX Port Impedance (J9)
50 Ω or High Z (Open)
Insertion Loss: TX Port to Output*
0.5 dB Max
Output Port Impedance (J5)
Insertion Loss: Output to RX Port * (J5–J9)
Transhybrid Loss: Isolation Between TX & RX*
* With Exact Impedance Matching on Output
Page 2–6
Value
50 Ω
14.5 dB Max
40 dB Min
February 2018
Chapter 2 Product Description
2.7 Environmental Requirements
This section provides three tables depicting the 50 W LPA-2/100 W LPA-2 environmental requirement
specifications, broken down as follows:
•
Environmental Requirements (table below)
•
Altitude Correction For Maximum Temperature Of Cooling Air (ANSI C93.5) (Table 2–5)
•
Altitude Dielectric Strength De-Rating for Air Insulation (Table 2–4)
Table 2–3. environmental requirements.
Ambient Temperature Range
Relative Humidity
Altitude
Transient Withstand Capability
1-Minute Hi-Pot Withstand
February 2018
-20 to + 60°C (derated per Table 2-5) of air-contacting
equipment
Up to 95% (non-condensing) at 40°C (for 96 hours
cumulative)
Up to 1,500 m (without derating)
Up to 6,000 m (using Table 2-4 and Table 2-5)
All external user interfaces meet SWC specifications of
ANSI C37.90.1 (1989) & IEEE 1613
DC input to alarm contact and to ground: 3,000 Vdc,
derated per Table 2-4.
Page 2–7
2
linear Power amplifier lPa–2 System manual
Table 2–4.
altitude Dielectric Strength
De-rating for air insulation.
Altitude (Meters)
Correction Factor
1,500
1.00
1,800
0.97
2,100
0.94
2,400
0.91
2,700
0.87
3,000
0.83
3,600
0.79
4,200
0.74
4,800
0.69
5,400
0.64
6,000
0.59
Table 2–5.
altitude Correction for max
Temp of Cooling air (ieee C93.5).
Altitude (Meters)
Short-Time
Long-Time
Usual
1,500
55
40
Unusual
3,000
48
33
Unusual
Unusual
Page 2–8
Temperatures (Degrees C)
2,000
4,000
53
43
38
28
Difference
From Usual
—
2
7
12
February 2018
Chapter 2 Product Description
2.8 Power Requirements and Dimensions
The power requirement specifications for the 50 W LPA-2 are shown in Table 2–6.
Table 2–7 shows the power requirement specifications for the 100 W LPA-2.
The weight and dimensions for the 50 W LPA-2 & 100 W LPA-2 are shown in Table 2–8.
2
Table 2–6.
50 W lPa-2 Power requirement Specifications.
50 W LPA-2
Nominal
Battery Voltage
Permissible
Voltage Range
110/125/250 Vdc
88–300 Vdc
48/60 Vdc
Max Supply Power (Watts) at Nominal Voltage
Standby
38–76 Vdc
28.8 W
5W
Transmit
50 W
Transmit
77.5 W
200 W
48 W
31.2 W
168 W
Table 2–7.
100 W lPa-2 Power requirement Specifications.
100 W LPA-2
Nominal
Battery Voltage
Permissible
Voltage Range
110/125/250 Vdc
88–300 Vdc
48/60 Vdc
Max Supply Power (Watts) at Nominal Voltage
Standby
38–76 Vdc
57.6 W
10 W
Transmit
100 W
Transmit
155 W
400 W
96 W
62.5 W
336 W
Table 2–8. lPa-2 Weight & Dimension Specifications.
Equipment
50 W LPA-2
100 W LPA-2
February 2018
Net Weight
lbs
12
24
Height
Kg
inches
10.9
7.0
5.4
3.5
Width
mm
inches
177.8
19.00
88.9
19.00
Depth
mm
inches
482.6
14.63
482.6
14.63
Rack
mm
Space
371.6
6 RU
371.6
3 RU
Page 2–9
Figure 2–2. main amp & option Board Block Diagram.
Figure 2–3. overload Protection & alarming Block Diagram.
2
F2
Fast-Blow Slow-Blow
10 A
12 A
F1
125/250V Fast-Blow Slow-Blow
4A
3A
48 V
DC IN
Figure 2–4. DC Power Supply Block Diagram.
Chapter 2 Product Description
Figure 2–5. lPa-2 main Board.
2
February 2018
Page 2–13
linear Power amplifier lPa–2 System manual
Table 2–9. Jumper Functions.
Board
Jumper
JMP1
JMP2
Main
JMP3
JMP4
Option
JMP1
(Table 2-11)
JMP2
Function
Controls input impedance of LPA-2
(Total input impedance should normally be 50 Ω to load the
driving carrier unit properly).
Controls phase shift of the LPA-2
(Normally set to 0°, except for a double chassis 100 W LPA-2
which requires one of the two units to be set to 0° & the other
to 180° for the 100 W combiner to work properly).
Enables or disables the front panel pushbutton switch capability for allowing insertion of an in-line power meter for testing.
Allows bypassing the option board when not installed.
Bypasses or inserts 100 W combiner & skewed hybrid options
individually.
Enables or disables 50 Ω termination on RX port of skewed
hybrid.
Table 2–10. Jumper Default Shipped Settings.
Board
Jumper
50 Ω Input Resistor
IN
JMP3
PB Switch for Test
Points
JMP4
Phase Shift
Option Board Installed
JMP1
Skewed Hybrid &
JMP2
Skewed Hybrid
RX Port Termination
(Table 3–3) 100 W Combiner
Option
Page 2–14
50 W Single
Chassis
JMP1
JMP2
Main
Name
Options
100 W Double Chassis
Chassis 1
Chassis 2
(with Option (w/o Option
Board)
Board)
IN
OUT
Enabled
Enabled
Enabled
NO for no Options
YES for Skewed
Hybrid
YES
NO
100 W Combiner
Always IN,
Skewed Hybrid
IN or OUT
(Depending on
Order)
Not Applicable
0°
Skewed Hybrid IN
(when ordered)
TERMINATE
0°
TERMINATE
180°
Not Applicable
February 2018
Chapter 2 Product Description
2
DaSheD line =
Skewed hybrid
Components
See Table
2-11 below
Figure 2–6. option Board.
Table 2–11. Part numbers / JmP1 Setting(s).
Option Ordered
Part Number
100 W Combiner Only Skewed Hybrid Only
CA20-PA5A2-003
CA20-PA5A2-002
Both 100 W Combiner
& Skewed Hybrid
CA20-PA5A2-001
JMP1
Setting
February 2018
Page 2–15
linear Power amplifier lPa–2 System manual
USER NOTES
Page 2–16
February 2018
Chapter 3. Applications
3.1 50 W / 100 W Applications
The 50 W LPA-2 and 100 W LPA-2 are used in
applications where the losses between the transmitting and receiving carrier units are greater than
a 10W system can handle. Usually this is due to
high loss on the power line because of a long line,
underground cable, a combination of underground
cable and overhead lines, or a line with untrapped
taps on it.
We recommend that before applying a high power
linear power amplifier (LPA-2), you do a thorough
analysis of the expected power line loss, including
all tuners, hybrids, coupling capacitors, etc. You
can often decrease total loss in a system by
properly tuning the line, using the optimum
hybrids for the application, removing any unnecessary attenuators in carrier receiver sets, and
selecting the proper carrier frequency. Using the
lowest possible carrier frequency (generally 30-50
kHz) is especially important on underground
cables, as their loss significantly increases at the
higher frequencies.
When applying high power LPA-2s, you must
treat the following three types of systems differently:
• Directional Comparison Blocking systems
• Phase Comparison Blocking systems
3.1.1 Directional Comparison Blocking
Systems
For Directional Comparison Blocking systems,
where the receiver can hear its own transmitter
without any problems, you do not need to connect
hybrids between the output of the LPA-2 and the
local receiver if the receiver is designed to handle
higher power. UPLC/UPLC-II™ and TC-10B can
handle up to 100 W input. The receiver of these
units can be bridged directly to the output of the
LPA-2. See Figure 3-1. You can only bridge the
carrier receiver across the output of the 100 W
LPA-2 if it is capable of sustaining 70.7 Vrms,
50Ω reference or 86.6 Vrms 75Ω reference across
its input without saturating. When using with a
ON-OFF DCB unit, you must set it up for 4-wire
operation (separate transmit and receive paths).
NOTE:
For TC-10B units, you must set the receiver
sensitivity jumper to NORM. This means
that on the RF Interface Module you would
set JU1 and JU5 in the OUT position to give
4-wire operation and JU6 to NORM to give
13 dB of attenuation to the incoming local
transmit signal. This is not needed on
UPLC/UPLC-II™ units.
• Systems using Frequency Shift (FSK)
Figure 3–1. on-oFF DCB Unit
with lPa-2 rF Connections.
Figure 3–2. Phase Comp. Blocking or FSK Sets
with lPa-2 rF Connections.
Copyright © ameTeK
3
linear Power amplifier lPa–2 System manual
3.1.2 Phase Comparison Blocking
For Phase Comparison Blocking Systems that
have an older type analog receiver, a skewed
hybrid must be used on the output of the LPA-2 to
prevent the local receiver from being over-driven
in addition to being set for 4-wire operation. See
Figure 3–2.
NOTE:
The TC-10B that has an old analog receiver
can be identified as it will have 2 separate
modules (a Receiver & Level Detector)
instead of the wider Universal Receiver
module.
3.1.3 Systems Using FSK
For systems using frequency shift carrier units, a
Skewed Hybrid option must also be used between
the output of the LPA-2 and the input of the
receiver, to prevent interference. The FSK unit
must be set for 4-wire operation, with separate TX
& RX coax connectors used. See Figure 3–2.
Page 3–2
February 2018
Chapter 4. Installation
4.1 Installing Your New LPA–2
Installing your LPA–2 is a three-step process:
1. Unpack and Inspect chassis
2. Mount the chassis
3. Connect your equipment and the dc power
source to the rear of the chassis
4.1.1 Unpacking & Inspecting
The LPA–2 is shipped with each chassis in its own
box. Special inserts are used to protect the
equipment from damage.
Whether you plan to install the unit immediately
or place it into storage, you should unpack the
box(es) and check to make sure all parts are
present and undamaged.
!
CAUTION
Each chassis has an identifying label on the front
panel and rear heat sink. The label tells you
whether the chassis is a 50 W LPA-2 or one of the
two chassis for a 100 W LPA-2. If it is a 100 W
LPA-2, the label also tells you whether it is chassis
1 (of 2) or chassis 2 (of 2). The label also includes
the serial number.
Storage
If you are setting the equipment aside before use,
be sure to store it in its special cartons (in a
moisture-free area) away from dust and other
foreign matter.
Installation Location
Install your LPA-2 in an area which is free from:
• Temperature exceeding specified environmental limits
UNPACK EACH PIECE OF EQUIPMENT
CAREFULLY SO THAT NO PARTS ARE LOST.
INSPECT THE CONDITION OF THE LPA–2 AS
YOU REMOVE IT FROM ITS CARTON(S). YOU
MUST REPORT ANY DAMAGED EQUIPMENT TO
THE CARRIER. DAMAGES ARE THE RESPONSIBILITY OF THE CARRIER, AND ALL DAMAGE
CLAIMS ARE MADE GOOD BY THE CARRIER.
PLEASE SEND A COPY OF ANY CLAIM TO
AMETEK.
• Corrosive fumes
• Dust
4.1.2 Mounting
The LPA–2 arrives already assembled. It is ready
to mount directly out of the carton. Coaxial cables
(and input T-connector for 100 W unit only) are
included.
Figure 4–1. rear View.
Copyright © ameTeK
4
linear Power amplifier lPa–2 System manual
You can mount your LPA–2 in any of the
following configurations:
• In a fixed-rack cabinet.
• In a swing-rack cabinet
• In an open rack.
!
CAUTION
IF YOU ARE MOUNTING YOUR LPA–2 IN A
SWING-RACK CABINET, MAKE SURE THAT
THE CABINET IS FIRMLY FASTENED BEFORE
OPENING THE RACK (TO PREVENT TIPPING).
Or mount it in your own, customer-specified
configuration.
To mount your chassis, refer to the following
figures for chassis dimensions and mounting
measurements.
Both the 50 W and 100 W chassis can be rack
mounted and have standard-spaced mounting
holes. Because of the heat produced by the LPA–
2, and also to allow for better air circulation
around the chassis, we recommend that you
always mount them at the top of a rack or panel. If
space isn’t a problem it is best to leave one (1)
rack unit (R.U.) of space, i.e., 1.75” (44.45 mm)
directly beneath and above the chassis. For the
100 W LPA-2, you must leave 1 RU of space
between its two chassis.
You make all necessary connections to the rear.
These include:
• Terminal Block Connections
• Coaxial Cables
• Ground Stud
All connections are made via the rear terminal
block (TB1) and the coaxial connectors (J5–J9)
per the connection diagram. The terminal block
screws are metric M3 (approx. #4 screw) and can
accept wire lugs with a max outer diameter of
0.32”. Maximum tightening torque for terminal
block screws is 10 in/lbs. For the DC input, #14
AWG wire is recommended with #20 AWG being
sufficient for the alarm connections. Maximum
current drain for 125Vdc is 1.6 A per chassis. A
#10 AWG wire for the #6-32 ground stud is
recommended, routed directly to the ground bar
and kept as short as reasonable.
All PC board jumpers are factory set based on the
catalog number. However, the top cover plate can
be removed and jumpers can be changed if the
application changes.
For example, if you ordered the LPA-2 as a 100 W
unit and then decided to use it as two 50 W units
or you no longer wanted to use the optional builtin hybrid, then jumpers will need to be changed.
Details of jumpers are shown in the block
diagrams and board layout drawings here in this
chapter.
This is critical if running the unit at
full power all the time. For example, in
a POTT/DCUB system where Guard
may be ran at full power instead of the
normal 1/10 power level.
4.1.3 Connecting to the Rear
Panel
The LPA–2 rear panel wiring connections are shown in diagrams at the end
of this chapter.
Figure 4–2. rear View, Close Up.
Page 4–2
February 2018
Chapter 4 installation
4
Figure 4–3a. Side View – Standard Projection mounting Position.
Figure 4–3b. optional Projection mounting Position (reversed mounting ears).
February 2018
Page 4–3
Figure 4–4. lPa–2 Front Dimensions.
Figure 4–5. Panel Drilling Plan for 2rU 50 W lPa-2 Chassis.
4
3
3) Three 12’ and one 1.5’ coax cables supplied with unit for inside of panel only. The short coax cable
is for connecting J5 temporarily to the short -term 50 Ω load for testing.
2) Normally open alarm contact shown connected but normally closed available also.
1) The driving carrier unit should be set for 4-wire operation with TX & RX ports separated on it.
NOTES:
2
3
Figure 4–6. 50 W lPa-2 Connection Diagram.
1
1
1
3
4
4
4
4
Chassis 2 of 2 – 50W Amp (No Option Board)
2
4) Six interconnecting coax cables & T-connector are supplied with unit for inside
of panel only. The short coax cable is for connecting J5 temporarily to the short
-term 50 Ω load for testing.
3) Normally open alarm contact shown connected but normally closed available
also.
2) The driving carrier unit should be set for 4-wire operation with TX & RX ports
separated on it.
1) For redundancy, it’s best to fuse each chassis separately.
Figure 4–7. 100 W lPa-2 Connection Diagram.
4
NOTES:
Chassis 1 of 2 – 50W Amp (with 100W
Combiner/Skewed Hybrid Option Board)
4
linear Power amplifier lPa–2 System manual
USER NOTES
Page 4–8
February 2018
Chapter 5. Test Equipment
Test Equipment
The same type of test equipment, used to test carrier units, is also used to test and adjust the
50 W LPA-2 and 100 W LPA-2. The following test equipment is recommended:
5
50 W / 100 W lPa-2 recommended Test equipment.
Equipment
High-Impedance Frequency Selective Level Meter
1 kHz to 1 MHz
• PowerComm Solutions PCA-4125
• Signal Crafters Model 110
• Spectrum Analyzer*
• Oscilloscope
Reflected Power Meter
• Signal Crafters Model 70
• PowerComm Solutions PCA-4125
Application
• Checking TX Level
• Checking RX level on optional
Skewed hybrid
Adjusting Line Tuner to Match
LPA-2 Output Impedance
* AMETEK can assist in providing an external device to measure up to 100 W.
!
CAUTION
WE RECOMMEND THAT THE USER OF THIS EQUIPMENT BECOME THOROUGHLY ACQUAINTED WITH
THE INFORMATION IN THESE INSTRUCTIONS BEFORE ENERGIZING THE 50 W LPA-2/100 W LPA-2 AND
ASSOCIATED ASSEMBLIES. YOU SHOULD NOT REMOVE OR INSERT PRINTED CIRCUIT MODULES
WHILE THE UNIT IS ENERGIZED. ALL INTEGRATED CIRCUITS USED ON THE MODULES ARE SENSITIVE
TO AND CAN BE DAMAGED BY THE DISCHARGE OF STATIC ELECTRICITY. YOU SHOULD ALWAYS
OBSERVE ELECTROSTATIC DISCHARGE PRECAUTIONS WHEN HANDLING MODULES OR INDIVIDUAL
COMPONENTS. FAILURE TO OBSERVE THESE PRECAUTIONS CAN RESULT IN COMPONENT DAMAGE.
Copyright © ameTeK
linear Power amplifier lPa–2 System manual
USER NOTES
Page 5–2
February 2018
Chapter 6. Adjustment
6.1 General Adjustment Information
All LPA-2s are shipped from the factory preadjusted for the recommended 5W (+37 dBm)
input to drive them to full power output. So, if you
are able to set your driving carrier unit to the 5W
full power output, then no adjustment should be
necessary on the LPA-2. However, the LPA-2 can
be driven with any power level between 2 W (+33
dBm) to 10W (+40 dBm), but it will require readjustment for the different input power level to give
the correct full power output. All power levels
measurements should be taken with a 50 Ω
reference impedance used on the meter.
Also, as-shipped jumper settings (Table 2–11) are
based on how the LPA-2 was ordered and will
work without any jumper setting changes if you
are using the unit as ordered. If you want to make
any special jumper settings, other than as-shipped
defaults, then remove the screws on the top cover
to access the main board to change them. Refer to
Figure 2–5 for location of jumpers and Table 2–9
for their function.
Following are step-by-step procedures to properly
power on and verify/adjust the 50 W LPA-2 and
100 W LPA-2.
Simplified connection drawings are shown to aid
in understanding where signal levels are being
measured and how the system should be
connected for testing. Also, refer to the front &
rear panel drawings in Chapter 2 for front test
point and rear connector locations.
Copyright © ameTeK
6
linear Power amplifier lPa–2 System manual
2
3
1
Figure 6–1. Simplified Connections – 50 W.
NOTES for Figure 6–1
1) The driving carrier unit must be set for 4-wire operation with TX & rX not connected together.
2) Connect to the short-term 50 Ω load for adjustment & testing only.
3) optional Skewed hybrid shown in dotted lines.
6.2 50 W Adjustment Procedure
1. Verify proper connections per the connection diagram, (Figure 6–1). Temporarily
terminate the LINE (J5) output of the 50 W
LPA-2 with the built-in 50 Ω high-wattage
load by connecting it to the SHORT-TERM
50 Ω LOAD connector above it with a coax
cable.
NOTE:
The 50 Ω load is located on the right
side wall of the chassis (viewed from
front). It will heat up but is protected
from overheating by a thermal switch.
The load can handle up to 80W continuously.
2. Make sure the LPA-2 is not powered up yet
and use the LPA-2 input as a load for the
driving carrier unit. With the driving carrier
Page 6–2
unit’s TX output connected to the AMP IN
(J6) coax connector it will be terminated in
a 50 Ω load located on the LPA-2’s input
that can handle up to 10W of power. Set the
high-power TX output level of the driving
carrier unit to 5W (+37 dBm) which will
produce 50W (+47 dBm) at the output of
the LPA-2. Set the low-power TX output
level of the driving carrier unit to 0.5W
(+27 dBm) which will produce 5W (+37
dBm) at the output of the LPA-2. (This is a
typical level for the low-power TX of the
driving carrier unit but it can be set for a
higher level if desired.) Key the driving
carrier unit to send low-power TX to the
LPA-2 when initially powered up so that
the LPA-2 can be verified at a low power
setting first before going to full power.
3. Power on the LPA-2 by sliding up the
recessed DC Power switch on the rear
February 2018
Chapter 6 initial adjustment
panel with a small screwdriver. Verify that
the green “AMP OK” LED illuminates. It
should always stay lit when powered on as
long as there is a 50 Ω load or properly
adjusted line tuner connected to the LINE
port (J5).
4. Verify the input level between the AMP IN
/ COMMON test points is equal to the lowpower TX level of the driving carrier unit.
5. Verify the following levels in the order
shown.
Driving
Carrier
Unit
Condition
LL Key
HL Key
LPA-2 Test Points
AMP IN / COM
LINE / COM
5W / +37dBm
50W/+47dBm(50Vrms)
0.5W / +27dBm 5W/+37dBm(15.8Vrms)
The full power (HL Key) output value
should be within +/– 0.3 dB or +/– 1 V of
the value shown above.
If this value needs to be adjusted, because
you are using a different drive level than
the recommended 0.5 W-LL / 5 W-HL, then
turn the front LEVEL ADJUST potentiometer (pot) with a small screwdriver.
Clockwise rotation of this pot increases
output signal level. Also, if desired, a
power meter’s input can be inserted into the
OUT/COMMON test points and the
meter’s output inserted into the LINE /
COMMON test points. Then the pushbutton switch can be pressed to insert the
meter for enough time to measure the
output power. The power meter should
measure a forward power of 50W and show
no or very low reflected power. (or VSWR
close to 1).
6. Power off the LPA-2 and remove the coax
connecting the 50 Ω load to the LINE J5
connector. Then instead connect the LINE
J5 connector to the coax going out to line
tuner (LMU) or into the system.
7. Power on the LPA-2 to verify the output
power remains at approximately 50W and
the reflected power is less than 15%. Very
high reflected power can cause the LPA-2
to temporarily go into shut-down/overload
mode to prevent damage until the reflected
power comes down. The LPA-2 should not
be readjusted at this point as the nonperfect 50 Ω load of the line tuner (LMU)
will cause a difference in the power level.
The greater the % reflected power, then the
greater the difference in measured LPA-2
output power level.
Figure 6–2. Front overlay.
February 2018
Page 6–3
6
linear Power amplifier lPa–2 System manual
2
3
1
Figure 6–3. Simplified Connections – 100 W.
NOTES for Figure 6–3
1) The driving carrier unit must be set for 4-wire operation with TX & rX not connected together.
2) Connect to the short-term 50 Ω load for adjustment & testing only.
3) optional Skewed hybrid shown in dotted lines.
6.3 100 W Adjustment Procedure
Two types of adjustment procedures are given:
• With factory settings (as shipped)
• Custom (due to different desired input
power level, changing out a failed part, or
changing the application of how the
amplifier will be used)
6.3.1 100 W Adjustment (as shipped
from factory)
1. Verify proper connections per the connection diagram, (Figure 6–3). Temporarily
terminate the LINE (J5) output of the
100W LPA-2 with the built-in 50 Ω highwattage load in chassis 1 of 2 by
connecting it to the SHORT-TERM 50 Ω
LOAD connector above it with a coax
cable.
Page 6–4
NOTE:
The 50 Ω load is located on the right side
wall of chassis (viewed from front). It will
heat up but is protected from overheating
by a thermal switch. The load can handle up
to 80W continuously and 100W for up to 2
minutes before disconnecting automatically. If this happens you must wait 10
minutes before reusing the load.
2. Make sure both chassis of the LPA-2 are
not powered up yet and use the LPA-2
input as a load for the driving carrier unit.
With the driving carrier unit’s TX output
connected to the AMP IN (J6) coax
connector, on both chassis’s of the LPA-2,
it will be terminated in a 50Ω load located
on the LPA-2’s input (chassis 1 of 2) that
can handle up to 10W of power. Set the
February 2018
Chapter 6 initial adjustment
high-power TX output level of the driving
carrier unit to 5W (+37 dBm) which will
produce 100W (+50 dBm) at the output of
the LPA-2. Set the low-power TX output
level of the driving carrier unit to 0.5W
which will produce 10W at the output of
the LPA-2. (This is a typical level for the
low-power TX of the driving carrier unit
but it can be set for a higher level if
desired.) Key the driving carrier unit to
send low-power TX to the LPA-2 when
initially powered up so that the LPA-2 can
be verified at a low power setting first
before going to full power.
3. Power on both chassis of the LPA-2 by
sliding up the recessed DC Power switch
on the rear panel with a small screwdriver.
Verify that the green “AMP OK” LED illuminates. It should always stay lit when
powered on as long as there is a 50 Ω load
or properly adjusted line tuner connected to
the LINE port (J5).
4. Verify the input level between the AMP IN
/ COMMON test points is equal to the lowpower TX level of the driving carrier unit.
5. Verify the following levels, in the order
shown, on chassis 1 of 2 only. (not on
chassis 2 of 2).
Driving
Carrier
Unit
(All measurements made on chassis 1 of 2)
LL Key
0.5W / +27dBm
Condition
HL Key
LPA-2 Test Points (Chassis 1 of 2)
AMP IN / COM
5W / +37dBm
LINE / COM
10W / +40dBm (22.4 Vrms)
100W / +50dBm (70.7 Vrms)
The full power (HL Key) output value
should be within +/– 0.3 dB or +/– 2 V of
the value shown above.
Also, if desired, a power meter’s input can
be inserted into the OUT / COMMON test
points and the meter’s output inserted into
the LINE / COMMON test points. Then the
pushbutton switch can be pressed to insert
the meter for enough time to measure the
output power. The power meter should
measure the forward power of 100W and
February 2018
should show no or very low reflected
power.
6. Power off the LPA-2 and remove the coax
connecting the 50 Ω load to the LINE J5
connector. Then instead connect the LINE
J5 connector to the coax going out to line
tuner (LMU) or into the system.
7. Power on the LPA-2 to verify the output
power remains at approximately 100W and
the reflected power is less than 15%. Very
high reflected power can cause the LPA-2
to go into shut-down/overload mode to
prevent damage until the reflected power
comes down. The greater the % reflected
power, then the greater the difference in
measured LPA-2 output power level.
6.3.2 100 W Custom Adjustment
1. Verify proper connections per the connection diagram, (Figure 6–3). Temporarily
terminate the LINE (J5) output of the
100W LPA-2 with the built-in 50 Ω highwattage load inside chassis 1 of 2 by
connecting it to the SHORT-TERM 50 Ω
LOAD connector above it with a coax
cable.
2. Make sure both chassis of the LPA-2 are
not powered up yet and use the LPA-2
input as a load for the driving carrier unit.
With the driving carrier unit’s TX output
connected to the AMP IN (J6) coax
connector it will be terminated in a 50Ω
load located on the LPA-2’s input (chassis
1 of 2) that can handle up to 10W of power.
Set the high-power TX output level of the
driving carrier unit to 5W (+37 dBm)
which will produce 100W (+50dBm) at the
output of the LPA-2. Set the low-power TX
output level of the driving carrier unit to
0.5W which will produce 10W at the output
of the LPA-2. (This is a typical level for the
low-power TX of the driving carrier unit
but it can be set for a higher level if
desired.) Key the driving carrier unit to
send high-power TX. Initial adjustment is
best done at full power.
Page 6–5
6
linear Power amplifier lPa–2 System manual
3. Turn the LEVEL ADJUST potentiometer
(pot) all the way down on both chassis’s (1
of 2 and 2 of 2). That is full counterclockwise rotation for at least 20 full turns
(zero gain setting).
4. Power on both chassis 1 & 2 by sliding up
the recessed DC Power switch on the rear
panels with a small screwdriver. Verify that
the green “AMP OK” LED illuminates. It
should always stay lit when powered on as
long as there is a 50 Ω load or properly
adjusted line tuner connected to the LINE
port (J5).
5. Verify the input level between the AMP IN
/ COMMON test points is equal to the lowpower TX level of the driving carrier unit.
6. Make all measurements on chassis 1 of 2.
But adjust both of the two chassis LEVEL
ADJUST pots starting with chassis 1 of 2
first. With the driving carrier unit keyed to
high-level, first use the chassis 1 of 2
LEVEL ADJUST pot to set the output level
between the LINE / COMMON test points
as shown in the table below.
Next, use the chassis 2 of 2 LEVEL
ADJUST pot to set the output level of
chassis 2 of 2. Measuring between the
100W NULL / COMMON test points
(chassis 1 of 2), set this level to a minimum
(null). This step balances the 2nd 50W
LPA-2 chassis’ output level with the first so
that they are both putting out 50W of
power. Finally measure the total output
level between the LINE / COMMON test
points of chassis 1 of 2 and verify it is at
100W (± 0.3dB or ± 2V). Then verify the
LPA-2 puts out approximately 10W with its
driving carrier unit keyed at low-level. This
low-level is not very critical and does not
have to be as accurate as the high-level.
7. Also, if desired, a power meter’s input can
be inserted into the OUT / COMMON test
points and the meter’s output inserted into
the LINE / COMMON test points. Then the
pushbutton switch can be pressed to insert
the meter for enough time to measure the
output power. The power meter can
measure the forward power of 100W and
should show no or very low reflected
power. The greater the % reflected power,
then the greater the difference in measured
LPA-2 output power level.
8. Power off the LPA-2 and remove the coax
connecting the 50 Ω load to the LINE J5
connector. Then instead connect the LINE
J5 connector to the coax going out to line
tuner (LMU) or into the system.
9. Power on the LPA-2 to verify the output
power remains at approximately 100W and
the reflected power is less than 15%. Very
high reflected power can cause the LPA-2
to go into shut-down/overload mode to
prevent damage until the reflected power
comes down.
NOTE:
Chassis 1 of 2 level is ¼ (–6dB) of the normal level because only one chassis is
outputting and half the power of one chassis is being lost in the “unbalanced”
combiner. Once it is balanced with chassis 2 of 2 there will be no loss in the combiner.
Driving
Carrier Unit
Condition
LL Key
LL Key
HL Key
HL Key
Page 6–6
LPA-2
Level Adj. Pot
LPA-2 Chassis 1 of 2 Test Points
(ALL measurements are made on chassis 1 of 2 only)
AMP IN / COM
Chassis 1 of 2 0.5 W / +27 dBm
100 W NULL / COM
–
2.5W / +34dBm (11.2 Vrms)
–
25W / +44dBm (35.4 Vrms)
Chassis 2 of 2 0.5 W / +27 dBm Min., < +9 dBm (0.6 Vrms)
Chassis 1 or 2
Chassis 2 of 2
5 W / +37 dBm
5 W / +37 dBm
LINE / COM
Min., < +20 dBm (2 Vrms)
10W / +40dBm (22.4 Vrms)
100W / +50dBm (70.7 Vrms)
February 2018
Chapter 7. Maintenance / Troubleshooting
7.1 Periodic Checks
If there are no alarms on the driving carrier unit or
the LPA-2, then checks can be on whatever
normal maintenance interval your company uses.
The following values should be measured.
• Full Power TX Output (within 0.5 dB of
last time measured value)
• TX Reflected Power % (or VSWR) –
should be less than 15% (VSWR < 2.3), the
lower the better performance.
We recommend that you keep a log book as a
visible record of periodic checks and to note any
gradual degradation in a unit’s performance.
7.2 Troubleshooting Sequence
CASE #1: If the green AMP OK LED goes off and
the red OVERLOAD LED illuminates, then the
alarm relay will deenergize giving an alarm. Also,
the LPA-2 may be pulsing on and off in the alarm
state, which usually indicates a problem with the
load on the LPA-2’s LINE port. If this happens
follow the steps below.
1. Power off the LPA-2 using the rear
ON/OFF slide switch.
2. Remove the coax from the LINE (J5) port
on the LPA-2 and connect it temporarily to
the 50 Ω short-term load (for J5) with a
coax cable. This removes any possibilities
of an improper load causing a problem with
the LPA-2.
3. Power on the LPA-2 using the rear
ON/OFF slide switch, and see if the green
LED illuminates and the red LED goes off.
If not, then verify the signal level on the
AMP IN test point is at the correct level
(normally 5W input for LPA-2 full output).
If it is too high, then the driving carrier unit
will need to be adjusted down in level.
4. Once the LPA-2 is proven to be working
properly with the 50 Ω short-term load,
then reconnect the system coax cable to the
LPA-2 and if the problem still exists, troubleshooting will need to be done to verify
the coax cable is good, the line tuner
(LMU) is good/adjusted properly for less
than 15% reflected power, and any other
devices between the line tuner and output
of the LPA-2 are good.
5. Verify the reflected power is less than 15%
CASE #2: If no LEDs are illuminated.
1. Verify that the rear ON/OFF slide switch is
in the ON position.
2. Verify that the proper dc voltage is applied
in the correct polarity to the rear terminal
block on terminals 1 (+) and 2 (–).
3. Power off the LPA-2 using the rear
ON/OFF slide switch. Remove fuse F1 on
the rear using a small screwdriver to twist
the cap off. Then verify if the fuse is good.
4. If needing to replace fuse F1 and the fuse
blows again, this usually indicates that
there is a failure due to either the Power
Supply in the LPA-2 partially failing or the
main amplifier itself failing.
5. The unit will need to be sent back to
AMETEK for repair. See page iii.
Copyright © ameTeK
7
linear Power amplifier lPa–2 System manual
USER NOTES
Page 7–2
February 2018
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