AMERITRON ALS-1306
1200 WATT 160-6 Meter NO TUNE
TMOS-FET AMPLIFIER
INSTRUCTION MANUAL
Revision 1A
116 Willow Road
Starkville, MS 39759 USA
662-323-8211
Table of Contents
QUICK START..............................................................................................................................4
INSTALLATION AND OPERATION........................................................................................4
P
LACEMENT
W
IRING
Power Mains........................................................................................................................... 4
Radio and Antenna Connections............................................................................................. 5
Operation................................................................................................................................ 6
AMPLIFIER FEATURES ............................................................................................................8
INTRODUCTION..........................................................................................................................8
POWER SUPPLY..........................................................................................................................9
Power Line Requirements....................................................................................................... 9
Power Supply Features........................................................................................................... 9
Power Supply Location........................................................................................................... 9
GENERAL INFORMATION.....................................................................................................10
Alert Codes............................................................................................................................ 10
Amplifier Overview............................................................................................................... 10
INSTALLATION.........................................................................................................................11
Installation Clearances......................................................................................................... 11
Installation Warnings............................................................................................................ 11
Installation, Wiring, and Connections.................................................................................. 12
Station Ground...................................................................................................................... 12
Safety and Lighting Grounding............................................................................................. 13
................................................................................................................................. 4
........................................................................................................................................ 4
INTERCONNECTION WIRING ..............................................................................................14
AMPLIFIER REAR PANEL......................................................................................................15
Optional Radio Interface Cables .......................................................................................... 16
FRONT PANEL...........................................................................................................................17
OPERATION ...............................................................................................................................18
MARS or CAP Operation...................................................................................................... 18
W
ARNING LIGHTS
...................................................................................................................... 18
Initial Operation ................................................................................................................... 19
ALC A
DJUSTMENT
.................................................................................................................... 20
ALS-1306 FUNCTIONAL OVERVIEW...................................................................................21
General Operation................................................................................................................ 21
Power Division...................................................................................................................... 21
PA Amplifiers........................................................................................................................ 21
2KWF6 Lowpass Filter Assembly......................................................................................... 22
Control and Protection Logic............................................................................................... 22
SWR....................................................................................................................................... 22
CIRCUIT BOARDS.....................................................................................................................23
BSW3..................................................................................................................................... 23
CB2 ....................................................................................................................................... 23
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MB2....................................................................................................................................... 23
RJ45 ...................................................................................................................................... 23
2KWF6.................................................................................................................................. 23
PA Boards............................................................................................................................. 23
PD8....................................................................................................................................... 23
RLA ....................................................................................................................................... 23
SWR....................................................................................................................................... 24
SCHEMATICS.............................................................................................................................24
Bandswitch BSW3................................................................................................................. 24
Control Board CB2............................................................................................................... 25
Metering Board MB2............................................................................................................ 27
Interface Connections RJ45.................................................................................................. 27
Filter 2KWF6........................................................................................................................ 28
Combiner 2000 watt CMB .................................................................................................... 29
Power Divider PD8............................................................................................................... 29
Relay Board .......................................................................................................................... 29
PA Module ............................................................................................................................ 30
SWR Board............................................................................................................................ 30
REFERENCE FIGURES AND DRAWINGS...........................................................................31
TABLES........................................................................................................................................31
DISCLAIMER..............................................................................................................................32
LIMITED WARRANTY...............................................................................................................32
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Quick Start
Thank you for purchasing this amplifier system. The ALS1306 is a 1200-watt nominal PEP
output amplifier and power supply system. This amplifier covers 160-6 meters. Nominal drive
power is 100 watts or less. This system will not and does not operate on the CB band.
The ALS1306 interfaces with most modern amateur radio transceivers, including band data
information. Band data connection will require purchasing an Ameritron interface cable for your
radio.
Carefully unpack this amplifier and power supply. Cabinets and controls can be broken, bent, or
dented with rough handling. Please inspect everything for physical shipping damage; this
includes cabinets and chassis. Ameritron does not package dented or damaged units. If your unit
is damaged or dented, including broken knobs or switches, it is always from handling somewhere
between Ameritron and the end user. In the event of cabinet damage or broken controls, please
retain all packing materials and containers so damage claims can be resolved.
Installation and Operation
Placement
WARNING: Do not block ventilation holes. Do not expose to water or external heat.
This unit is two units, a power supply and an amplifier section. The power supply, within limits
of cable length, can be placed out of the way. The amplifier section should be in a convenient
location within arm’s reach of the operating position.
Wiring
Power Mains
1.) This amplifier requires a 200-260 Vac, 50-400 Hz, 15-ampere or larger mains supply. This
range includes all typical power lines worldwide, including USA 240-volt systems
(sometimes incorrectly referred to as “220 volt”).
2.) The plug is a NEMA 6-15P, 250 maximum Vac at 15 amperes. This is a standard USA
250V plug with a safety ground pin
3.) The amplifier’s power supply system contains two 30-ampere 50-volt supplies, one for
HV1 and the other for HV2. The supply can be damaged by operation with voltages below
200 volts or above 260 volts.
4.) Larger power wiring will not help performance or power unless amplifier high voltage is
unstable.
5.) While not recommended, the power supply can be rewired for 100-130 Vac operation.
The increase in power line current with reduced power line voltage will limit amplifier
power.
6.) The ALS-1306 power supply system is voltage regulated. You should see very little
change in HV1 and HV2 with amplifier power. Less than 3 volts change from the 50Vdc
nominal voltage is normal.
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7.) The ALS-1306 has two power supply boards in the power supply. Exceeding safe power
supply current on any supply line will force the overloaded supply into shutdown.
Shutdown is reset by turning the main power switch off for a brief time. If the power
supply has a permanent overload or the supply has failed, it will not reset.
Radio and Antenna Connections
WARNING: Forcing connector engagement can result in permanent connector damage.
Solder on the outside of center pins or bent pins are primary causes of female connector
damage. External solder or bent center pins will permanently damage the female.
Do not use Line Isolators on amplifier RF cables. The chassis of the amplifier should be at
the same RF potential as all other desk equipment. Shield isolators allow equipment to float
to different RF chassis potentials. Different chassis potentials are exactly what we do not
want, and isolators on desk coaxial cables encourage different potentials. It is better to cure
RF problems outside the operating position whenever possible.
1.) RF connections are through standard UHF female connectors. Use good cables with
quality UHF male (PL259) connectors. The output cable must safely handle at least 1200
watts.
2.) Look at the connectors. The amplifier‘s female connectors have notches on the outer
thread edge. The cable males should have protruding tabs on the inner shell beyond the
center pin insulator. These tabs and notches prevent unwanted connector rotation. The
male’s tab or tabs must be aligned with the female’s notches. This interlocking prevents
connector rotation.
3.) With a firm handgrip, gradually tighten RF connectors while making sure the male tab
interlocks with the amplifier’s female connector notch. Do not use excessive force on
connectors. Check for proper tightness and seating by wiggling and flexing the cables
near the connector and watching for any indications of abnormal male connector
movement, and by wiggling the cable while hand tightening the male shell. If done
properly, the connector will be solidly locked without need for pliers or other tools
4.) ALC and Relay (keying) connectors are phono females. The phono males from external
cables should push directly in with a snug fit.
5.) The Relay line has low-voltage (<12V) low current (<20 mA). Transmit is enabled by
pulling the Relay line to ground with a relay contact or transistor. Read your radio
manual. Unless you have a very unusual radio, your radio will directly key the amplifier.
6.) The remote and radio band data connectors are specialized connections. They are for use
with Ameritron supplied cables only.
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Operation
This amplifier has alert codes. SWR, PA, TX, and band switch lamps indicate operational faults.
Operational faults reset by placing the amplifier in standby momentarily. The following table
applies to faults:
Warning
light Steady
SWR TX
SWR, PA Band Wrong filter
PA TX PA FET too hot
Warning
light Flash
Fault Cause or Cure
Antenna Reflected
Power
High antenna SWR or
intermittent antenna or feed line
connection
Exciter or amplifier on
incompatible band, filter failure
Excessive power for duty cycle
or SWR, lack of proper airflow
PA Combiner unbalance
REM, PA
10M, PA,
TX
Illegal 11 meter Excessive 27 MHz signal level
No or wrong band when
on remote
Defective or improper remote
cable, or bad radio band data
information
Before attempting operation:
1.) This amplifier is optimized for a 50-ohm load. Be sure your antenna system 50-ohm
SWR is as low as possible. As SWR increases from 1:1, either heat or distortion
will increase.
2.) Be sure your antenna system, including any lighting protection devices, will safely
handle high power.
3.) Connectors, cables, and antennas must not have loose connections or insulation
issues.
4.) Your exciter must be less than 100 watts output.
5.) Power mains should capable of 15 amperes, reasonably stable, and 200-260 volts.
6.) The low pass filters cut off just above traditional primary bands. This means
primary filters are used on WARC bands. Some radios do not supply enough band
data to know the exact band, so with some radios the amplifier band data displays
the next higher primary band above a WARC band. Do not be alarmed if, for
example, 15 meters illuminates when 17 meters is selected on some radios.
7.) The amplifier will automatically attempt to reduce power if it appears thermal
limits will be reached.
8.) The amplifier will shut off if an incorrect band is selected, if antenna SWR is too
high (even for an instant), if thermal limits are reached, or if there is a catastrophic
failure.
9.) The alert codes are in a table above on page 10.
10.) The ALS-1306 metering reads peak envelope power on all RF power functions.
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With proper installation, basic operation is straightforward:
1.) Set the bandswitch to the desired band. This happens automatically in the REM position
with a suitable radio interface cable
2.) Set the exciter or transceiver to the desired power below 100-watts.
3.) Place the standby switch in the operate position
4.) Transmit, and watching Forward Power metering, be sure power does not exceed 1200-
watts on peaks.
5.) For high duty cycle modes and long transmissions, reduce power. The amplifier will
attempt to reduce power if the FETs approach safe limits.
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Amplifier Features
This amplifier provides the following standard features:
• 160- through 6-meter operation, full-power on six meters
• Eight conservative linear-service rated, 50-volt MOSFET transistors
• New push-pull stripline PA layout with exceptional VHF performance
• Energy-efficient solid-state design greatly reduces heat, <100-watts power line draw on
receive
• Exceptional harmonic suppression
• Operational in a few seconds, no long filament warm-up time
• Clean layout with easy-to-service modular construction
• Quiet variable-speed forced-air cooling system
• Power module current and voltage meters with LED illumination
• Accurate PEP Forward and PEP Reflected output power metering
• Power module balance metering with PA unbalance protection
• Reflected power protection
• Thermal overload protection
• Bandswitch error protection
• Easy to understand front panel LED indicators for rapid fault-error diagnosis
• Standard negative-going ALC output with front panel adjustment
• ALC metering and ALC LED indicator
• Fully-regulated external power supply
• Compact size 17.5” deep x 7” high x 10.5” wide
• Weight amplifier section 23 pounds
Introduction
The Ameritron ALS-1306 is 1200-watt nominal output, 160 through 6-meter amateur radio band,
solid-state amplifier. The ALS-1306 uses eight 50-volt, conservatively rated, linear RF
MOSFETs. These MOSFETs are specifically designed for linear power amplifier applications,
not class C or pulse service. They provide exceptionally low SSB distortion when compared to
other solid-state devices. Fan speed is regulated by temperature sensors; assuring conservative
cooling with minimal noise.
Nominal driving power is 100-watts for 1200-watts output (approximately 11 dB gain) on most
bands. The compact 10” wide by 6-1/2” high amplifier package (depth only 18”) fits nearly any
station configuration. The attractive desktop amplifier unit weighs only 24 pounds.
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An external 50-volt 50-ampere regulated power supply powers the ALS-1306. The supply is
wired for 240 VAC (200-260 VAC, 50-60 Hz, 15 amperes), but can be rewired for 120 VAC
operation for lighter duty operation.
Power Supply
The external power supply for the ALS-1306 is a voltage-regulated current-limited switching
supply. It contains 14-volt positive and negative supplies, as well as dual 50-volt 25-ampere
continuous (30-ampere peak) fully current-limited supplies. Each PA (power amplifier) module
in the ALS-1306 operates from independent 50-volt modules, giving a total dc supply rating of
2500 watts average power and 3000 watts peak power to the power amplifier modules.
Power supply to amplifier interconnections are through a heavy-duty cable using a large Cinch
Jones connector.
Power Line Requirements
This amplifier ships wired for a nominal mains voltage of 230 Vac. Maximum average powerline current at full power output is 12 amperes at 240 volts. Two 250-volt 15-ampere fuses fuse
the power line. The switching power supply automatically adapts to any mains voltage between
200 Vac and 260 Vac, and does not require adjustments or tap changes within that range.
Note: 120-volt power mains operation is possible with a reduction in CW or RTTY power.
Because average power is very low, SSB operation is unaffected by 120-volt operation. 120-V
fuse size is 25-amperes maximum.
Power Supply Features
• Efficient operation from 200-260 volts ac (12 amperes typical at full output power).
• Low standby and receive power drain, typically less than 100-watts.
• Generator and inverter friendly with acceptable power line frequency range 40 to 400 Hz.
• Fully regulated current-limited outputs.
• Step-start to limit stress on power supply components.
• Exceptional filtering and RFI suppression eliminates receiver birdies common to most
SMPS.
• Compact lightweight design.
Power Supply Location
Locate the power supply in a convenient ventilated area near the amplifier location. Avoid
placing the power supply next to sensitive equipment, such as audio processors, transceivers, or
microphones. For safety, ground the wing nut stud on the supply rear to the station ground buss.
The station ground buss should comply with National Electrical Codes. NEC and fire protection
codes mandate directly bonding of station grounds to the power-line entrance ground. If station
ground rods are not bonded to the utility entrance ground, likelihood of equipment or property
damage and personal risk increases.
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General Information
Alert Codes
The SWR, PA, TX lamps, and band switch lamps indicate operational faults. Operational faults
reset by placing the amplifier in standby. The following table applies to faults:
Warning
light Steady
SWR TX
SWR, PA Band Wrong filter
PA TX PA FET too hot
PA Combiner unbalance
REM, PA
Warning
light Flash
10M, PA,
TX
Fault Cause or Cure
Antenna Reflected
Power
High antenna SWR or
intermittent antenna or feed line
connection
Exciter or amplifier on
incompatible band, filter failure
Excessive power for duty cycle
or SWR, lack of proper airflow
Illegal 11 meter Excessive 27 MHz signal level
No or wrong band when
on remote
Defective or improper remote
cable, or bad radio band data
information
Amplifier Overview
The Ameritron ALS-1306 is a solid-state, 1200-watt nominal RF output power, 1.8-54 MHz
amplifier. The ALS-1306 meets or exceeds all FCC requirements governing amateur radio
external power amplifiers.
The ALS-1306 uses four pairs of exceptionally low distortion, push-pull MRF-150 (or
equivalent) SSB RF power transistors. The characteristics of linear high-voltage FETs are very
much like those of triode vacuum tubes. While this amplifier will run more than 1200 watts PEP
output, linearity might suffer. Ameritron recommends running 1200 watts or less peak power for
maximum linearity. If these instructions are followed this amplifier will have comparable IM
performance to the best vacuum tube linear amplifiers.
Temperature sensors on each PA (power amplifier) module monitor heat. Bias and fan speed
track FET temperature. The ALS-1306 protection circuitry reduces power as transistors approach
conservative thermal limits, and disables the amplifier before transistor exceed safe operating
temperature limits.
Harmonic suppression comes from push-pull operation of linear devices, followed by highquality 5-pole low-pass filters. Many amplifiers use inexpensive ceramic disc or mica capacitors.
Lead inductance of mica or disc capacitors reduces high-order harmonic suppression. This
amplifier uses quality multi-layer high voltage chip capacitors.
This amplifier greatly exceeds FCC harmonic requirements. HF harmonic suppression typically
10-15 times better than FCC mandated suppression levels. Harmonics are practically
immeasurable on all television channels. An external low-pass filter has minimal effect with this
amplifier.
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