AMERITRON ALS-1406/S User manual

AMERITRON ALS-1406/S
1200 WATT 160-6 Meter NO TUNE
LDMOS-FET AMPLIFIER
INSTRUCTION MANUAL
WARNING!
NEVER APPLY POWER TO THIS AMPLIFIER WITH THE COVER REMOVED!
CONTACT WITH THE POWER SUPPLY VOLTAGES IN THIS AMPLIFIER CAN BE FATAL!
PLEASE READ THIS MANUAL BEFORE OPERATING THIS EQUIPMENT!
Factory
116 Willow Road
Starkville, MS 39759 USA
662-323-8211
Version 0
Printed in the USA

Table of Content
AMPLIFIER FEATURES ............................................................................................................................... 4
POWER SUPPLY FEATURES ..................................................................................................................... 4
QUICK START .............................................................................................................................................. 5
Installation and Ope ation......................................................................................................................... 5
Placement............................................................................................................................................. 5
Wi ing........................................................................................................................................................ 5
Powe Mains ......................................................................................................................................... 5
Radio and Antenna Connections.......................................................................................................... 6
Ope ation .................................................................................................................................................. 7
INTRODUCTION........................................................................................................................................... 9
Powe Supply............................................................................................................................................ 9
Powe Line Requi ements .................................................................................................................... 9
Powe Supply Location......................................................................................................................... 9
GENERAL INFORMATION......................................................................................................................... 10
Amplifie Ove view.............................................................................................................................. 10
INSTALLATION........................................................................................................................................... 11
Installation Clea ances ........................................................................................................................... 11
Installation Wa nings .............................................................................................................................. 11
Accesso y Equipment and Devices .................................................................................................... 11
Installation, Wi ing, and Connections ................................................................................................. 11
Safety and Lightning G ounding......................................................................................................... 12
Station RF G ound.............................................................................................................................. 12
Coaxial Line Isolato s ......................................................................................................................... 13
INTERCONNECTION WIRING................................................................................................................... 14
FRONT PANEL CONTROLS ...................................................................................................................... 15
AMPLIFIER REAR PANEL ......................................................................................................................... 16
INTERCONNECTIONS............................................................................................................................... 17
Optional Radio Inte face Cables ........................................................................................................ 18
OPERATION ............................................................................................................................................... 19
MARS o CAP Ope ation ........................................................................................................................ 19
Initial Ope ation....................................................................................................................................... 20
ALC Adjustment...................................................................................................................................... 21
High Duty Cycle Modes .......................................................................................................................... 21
Wa ning Lights........................................................................................................................................ 22
RF EXPOSURE INFORMATION ................................................................................................................ 22
ALS-1300SPS INTERCONNECT DIAGRAM ............................................................................................. 25
AC Mains Selection ................................................................................................................................ 25
50-ALS600SPS-1B Powe Supply Module......................................................................................... 25
50-SPS600-1B Powe Supply Module ............................................................................................... 26
ALS-1406 LIMITED WARRANTY ............................................................................................................... 28
Table
Table 1 Wa ning Ale t Codes........................................................................................................................ 7
Table 2 Optional Radio Inte face Cables .................................................................................................... 18
Table 3 Band F equency Limits .................................................................................................................. 19
Table 4 Wa ning Lights ............................................................................................................................... 22
Table 5 RF Exposu e Distance Cha t ......................................................................................................... 23
Table 6 App oximate Antenna Gain fo Some Common Antennas ............................................................ 24

Figure
Figu e 1 Basic Inte connect ........................................................................................................................ 14
Figu e 2 Basic Inte connect with Radio Inte face Cable............................................................................. 14
Figu e 3 Inte connect with Tune and no KEY LOOP ................................................................................. 14
Figu e 4 Inte connect using KEY LOOP ..................................................................................................... 14
Figu e 5 Amplifie F ont Panel .................................................................................................................... 15
Figu e 6 Amplifie Back Panel..................................................................................................................... 16
Figu e 7 50-ALS600SPS-1B Line Voltage Jumpe s ................................................................................... 25
Figu e 8 50-SPS600-1B Line Voltage Jumpe s .......................................................................................... 26
Ve sion 0 03-22-2021
DISCLAIMER
Information in this manual is designed for user purposes only and is not intended to
supersede information contained in customer regulations, technical manuals/documents,
positional handbooks, or other official publications. The copy of this manual provided to the
customer will not be updated to reflect current data.
Customers using this manual should report errors or omissions, recommendations for
improvements, or other comments to Ameritron 11 Willow Road, Starkville, MS 39759. Phone:
( 2) 323-8211; FAX: ( 2) 323- 551. Business hours: M-F 8-4:30 CST.

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Amplifier Feature
This amplifier provides the following standard features:
• 160 through 6 meter operation
• Two conservative linear-service rated, 50-volt dual LD OS FET transistor packages
• 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
Power Supply Feature
• Efficient operation from 200 to 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 S PS.
• Compact lightweight design.

5
Quick Start
Thank you for purchasing this amplifier system. The ALS-1406 is a 1200-watt nominal
PEP output amplifier and power supply system. This amplifier covers 160 to 6 meters.
Nominal drive power is 100 watts or less. This system will not and does not operate on
the CB band.
The ALS-1406 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 bloc ventilation holes. Do not expose to water or external
heat.
This unit is two components, a power supply and an amplifier section. The power
supply, within limits of cable length, may 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 to 260 Vac, 50 to 400 Hz, 15-ampere or larger mains
supply. This range includes all typical power lines worldwide, including USA 240
volt systems.
2.) The plug is a NE A 6-15P, 250 maximum Vac at 15 amperes. This is a standard
USA 250V plug with a safety ground pin. Do not remove the 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 to 130 Vac
operation. The increase in power line current with reduced power line voltage will
limit amplifier power.

6
6.) The ALS-1406 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.
7.) The ALS-1406 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. Power Supply 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 (<14 V) 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.

7
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
Warning
Light
Flashing
Fault Cause or Cure
SWR TX Antenna Reflected
Power
High antenna SWR or
intermittent antenna or feed line
connection
SWR, PA Band Wrong filter Exciter or amplifier on
incompatible band, filter failure
PA TX PA FET too hot Excessive power for duty cycle
or SWR, lack of proper airflow
PA Combiner unbalance
10 , PA,
TX
Illegal 11 meter
operation Excessive 27 Hz signal level
RE , PA No or wrong band when
on remote
Defective or improper remote
cable, or bad radio band data
information
Table 1 Warning Alert Codes
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 lightning 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 to
260 volts.
6.) The low pass filters cut off just above traditional primary bands. This means
primary filters are used on the 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 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.
8.) The ALS-1406 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 RE
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 the power. The
amplifier will shut down if the FETs reach the maximum safe temperature limits.

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Introduction
The Ameritron ALS-1406 is 1200-watt nominal output, 160 through 6-meter amateur
radio band, solid-state amplifier. The ALS-1406 uses two 50-volt, conservatively rated,
linear RFE6VP5600HR6 dual LD OS FETs. These LD OS FETs are specifically
designed for broadcast power amplifier applications. 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 or less 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.
An external 50-volt 50-ampere regulated power supply powers the ALS-1406. 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-1406 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-1406 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. aximum average
power-line 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 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 bus. The station ground bus 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
Amplifier Overview
The Ameritron ALS-1406 is a solid-state, 1200-watt nominal RF output power, 1.8 to 54
Hz amplifier. The ALS-1406 meets or exceeds all FCC requirements governing
amateur radio external power amplifiers.
The ALS-1406 uses two exceptionally low distortion RFE6VP5600HR6 dual LD OS
SSB RF power transistors in push-pull. 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 I performance to the best vacuum tube linear
amplifiers.
There are multiple temperature sensors on each PA (power amplifier) module are to
monitor heat to adjust bias and fan speed. The ALS-1406 will disable the amplifier
before the transistors exceed the safe operating temperature limits.
Harmonic suppression comes from push-pull operation of linear devices, followed by
high-quality 5-pole low-pass filters. any 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 to 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.
Antenna switching is through a pair of sequenced miniature relays on a plug-in module.
This facilitates relay servicing or maintenance. Relay switching time is approximately
five to ten milliseconds. The T/R “Relay” control jack is well within the range of almost
any transceiver or radio. The “Relay” jack has an open circuit voltage of 14 volts, and
closed circuit current less than 20 mA. Virtually any modern amateur radio will directly
key this amplifier.
This amplifier includes full metering using large easy-to-read conventional panel meters.
The meters read all critical parameters including forward and reflected peak envelope
RF power.

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In tallation
Please look your amplifier and power supply over carefully. Observe the air inlet and
outlet ventilation holes. Facing the amplifier front panel, the cooling air inlets are on the
top left and lower right side, including the right bottom. The warm air outlet is on the
lower left side of the cabinet as viewed from the normal operating position (front view).
While outlet air will not be particularly warm, it is never a good idea to have warm air
blow into heat sensitive equipment, such as transceivers or other power amplifiers.
Have the same consideration for your new amplifier and power supply. Be sure the air
inlet temperature is not substantially above normal room temperature. Ideally, the air
inlet temperatures should be below 32° C or 90° F, although temperatures up to 41° C
or 106° F are permissible. If ambient temperatures exceed these limits it might become
necessary to reduce duty cycle or power.
Warning: Do not block cooling air inlets and outlets!
Never expose the amplifier to water or mist.
Installation Clearances
The amplifier must have a clear area to the bottom, both sides, and top for proper
airflow, and to the rear for interconnection wiring. It is especially important to avoid
obstructions that block the air inlet on the top left, as well as both lower sides. Two
inches clearance is normally adequate for full ventilation. Keep any papers or loose
objects that might impede airflow away from the air inlets and outlets.
Locate the amplifier and power supply away from sensitive equipment such as
microphones, audio processing equipment, or low level audio or radio frequency
amplifiers. Generally, the best location for the power supply is below the operating desk
and away from antenna feed lines. This will keep fan noise and any RF coupling to a
minimum.
The power supply has an air inlet at the rear, and air outlets on the top. The highly
efficient power supply produces very little heat, but the inlet and outlet must remain
open to normal room temperature air.
Installation Warnings
Accessory Equipment and Devices
One of the most common causes of amplifier failures or erratic fault protection alarms is
installation of antenna switches, lightning protection devices, or baluns with lightning
spark gaps in high SWR lines. If your antenna system has an SWR high enough to
require an antenna tuner, do not use 50-ohm lightning protection devices after the tuner.
Installation, Wirin , and Connections
The power supply is factory wired for 200 to 260 Vac. It uses a standard NE A-6-15P
15-ampere 240-volt plug. The round center pin is the safety ground. Do not remove the
safety ground.
CAUTION! Before connecting the power supply to an electrical outlet, always be sure
you have completed the following four steps:
1. Insert the 15-ampere 250V fuses into the two black fuse caps.

12
2. Insert the fuse and cap assemblies into the power supply’s fuse holders. The
fuses lock in place with a quarter turn.
3. Connect the power supply to the amplifier.
4. Be sure the amplifier power switch is off.
Caution! Fuses have both voltage and current ratings. Use only
2 0V rated fuses in this device. The voltage rating is generally
marked on fuses. DO NOT use automotive-type low voltage fuses in
any power line application. For 240-volt operation, 1 -ampere fast
blow fuses are required.
Warning: Never insert the power supply cord into the outlet until
you have completed the four steps above!
Position the amplifier at or near the desired location on your operating desk so you have
access to the rear panel, and connect the rear panel cables. Do not connect the power
mains at this time!
Safety and Li htnin Groundin
The power supply cabinet grounds through a safety ground pin on the power plug. This
system depends on a properly wired power outlet.
Lightning protection grounds do very little good at the operating desk. Lightning
protection grounds belong at the antenna cable entrance to the building. Station ground
rods must always be electrically bonded, with low impedance and resistance, to the
power line entrance ground. The national electrical code in the USA prohibits isolated
ground systems at a dwelling entrance. Isolated ground rods or systems connected to
conductors entering a dwelling increase the chances of damage from storms, and
increase fire hazard and shock risk.
RF grounds generally belong at the antenna, or at the feed line entrance. With the
special exception of a small floating counterpoise grounds, RF grounds at or very near
the dwelling should bond into the mains ground outside the dwelling. This is especially
true with earth contact grounds.
There is a ground lug on the amplifier rear panel. This ground lug provides a convenient
chassis connection for operating positions with ground bus on the desk. A station
ground bus helps ensure desk area equipment cabinets are close to the same electrical
potential for radio frequencies and lower. Equipment ground lugs are NOT for
independent wires or connections to external ground rods or ground systems from each
piece of equipment. They are for connection to a desktop ground bus system, if you
prefer to use such a system. Independent wire connections are counterproductive, the
opposite of good practices.
Never use RF isolators between the amplifier and radio. Never use long independent
wires to external ground. Never connect desk equipment to ground rods that are not
bonded to the mains ground rod.
Station RF Ground
Common rumor is that a station equipment ground reduces RFI (radio frequency
interference), reduces lightning damage, or improves signal levels. Generally, changes
in RFI or signal quality, with the addition or removal of a station ground, indicate an

13
antenna or feed line installation problem. Typical problems causing desktop RF
problems include the following:
1. Lack of suitable baluns or chokes.
2. Improper feed line routing near antennas, or improperly designed antennas.
3. Antennas too close to the operating position.
4. Poor equipment cabinet design, such as non-bonded or grounded equipment
covers or panels.
5. Poorly designed low-level audio line shield entrances, such as shields allowed to
enter cabinets instead of grounding at the enclosure entrance.
6. Improper antenna feed line building entrance, lacking a properly grounded
entrance panel.
Rather than patching a system problem at the desk, it is much better to correct defects
at the source.
Coaxial Line Isolators
Never install coaxial line isolators between desktop radio equipment. The goal of every
operating position is to maintain all equipment cabinets and housings at the same RF
potential. Isolators on or near the desk are contrary to this goal, and actually promote or
encourage cabinet or chassis RF potential differences. If an RF problem appears at the
operating position the correction, repair, or replacement of defective equipment is in
order.
The only proper line-isolator installation points are either just outside the operating room
entrance and/or close to the problem’s actual source. If the desktop has defective
cables or connectors, or poor equipment cabinet design, locate and correct the actual
problem.

14
Interconnection Wiring
Figure 1 Basic Interconnect
Figure 2 Basic Interconnect with Radio Interface Cable
Figure 3 Interconnect with Tuner and no KE LOOP
Figure 4 Interconnect using KE LOOP

15
Front Panel Control
Figure 5 Amplifier Front Panel
The front panel contains the following indicators and controls. To prevent damage,
become familiar with the front panel before operating the amplifier.
1 PA Module Current meters
2 Forward Power meter and Multimeter (reflected power, module RF balance,
ALC, and odule supply voltages) selected by knob 7.
3 Band or REMote selector knob.
4 Backlit Band and REMote LED indicators.
5 ALC limit adjustment.
6 Backlit Function and Fault Warning LED indicators.
7 Multimeter (meter 2) scale function selector knob.
8 Operate/Standby switch, also resets fault warnings.
9 Main Power, also resets power supply overload.
Note: The right-hand meter’s left scale-arc (fig.5 ref 2) continuously indicates forward peak
envelope power (PEP) output directly in kilowatts. It is 100 watts, or 0.1 kW, per meter scale
picket. PEP has no fixed relationship to long-term average power except, for constant
amplitude carriers like a steady CW carrier, when PEP and average powers are equal. PEP is
the highest average power during one (or more) radio frequency cycle(s) at the modulation
envelope crest.
The right-hand meter’s rightmost scale-arc is used for PEP reflected power in watts and
combiner imbalance on the upper scale numbers and pickets. Notice power meter calibrations
are not evenly spaced. Lower scale numbers and pickets are evenly spaced, and are for other
functions. The lower right scale is used for relative ALC setting and power amplifier modules
HV (0-70 volts).

16
Amplifier Rear Panel
Figure 6 Amplifier Back Panel
POWER INPUT The power supply should be unplugged before installing or
removing this connector. This connector is indexed by a slight
vertical offset in the two round index pins. ate the round
pins and holes. Seat the male plug fully onto the amplifier rear
panel male connector pins. After seating, the power supply
can be plugged into the AC mains outlet.
ALC Optional connection. Connects to radio ALC input.
RELAY Connect to radio amplifier keying line. Radio must pull this
line below 2 volts to transmit.
KEY LOOP Output for remote tuner use.
KEY LOOP Switch Switch to turn on and off the KEY LOOP function.
GND Connect to station ground bus, if available. This connection is
primarily for extra safety.
RF IN Connect through good 50-ohm coaxial cable of any
reasonable length to radio’s antenna output connector. This
can be a smaller cable, such as RG-58/U.
RF OUT To 50-ohm antenna, antenna tuner, power meter. This is the
high power output. 50-ohm coaxial cable and system beyond
must safely handle at least 1200 watts.
RADIO INTERFACE This connector is for use with Ameritron radio interface
cables. It allows automatic band selection (following the
radio). It also provides amplifier actuation in transmit mode
with some radios.

17
REMOTE These RJ45 connectors are for an Ameritron remote control
head, or remote operation with an interface box. It provides
access to controls, including most metering functions.
Interconnection
1. If you use a desktop grounding bus system, connect the station ground bus to
the amplifier’s rear panel wing nut. National safety codes require the station
ground electrically bond to the power mains safety ground at the building
entrance. Do not connect the amplifier to its own isolated ground rod or ground
system.
2. Connect the power supply to the amplifier.
3. Connect the RELAY line to the transceiver’s amplifier control port. This port is
usually described or defined in the amplifier interfacing section of the radio or
transceiver manual. This port must pull low for transmit, and be open circuit when
receiving. Relay control voltage from the ALS-1406 is 13 volts positive with only
15 mA current. You should always check your transceiver’s manual, but almost
any standard transceiver directly interfaces with this amplifier.
4. Connect the RF OUT (output) port to the appropriate point in your station. This is
the high power RF output cable. This connection would go to your 1500-watt
rated Power/SWR meter, antenna, or antenna matching device. Good quality
ini-8 or RG-8X cables are acceptable for anything but RTTY use, although
larger RG-8 style cables are normally preferred. Your antenna matching
system, or antenna tuner, must connect to this port.
5. Connect the IN connector to your transceiver. Do not install any active antenna
matching devices on this port. In general, the shortest and most direct cable
connection is best, although high quality cables can be very long without adverse
effect on performance. RG-58/U or ini-8 (RG-8X) style cables are acceptable.
You should ne er use a tuner of any type on the amplifier input, nor should
you dri e this amplifier with o er 100 watts peak en elope power.
6. The ALC line is optional. In general, transceiver internal ALC is all that is
necessary. The ALC monitors the RF output power and reflected power supplied
by the ALS-1406 to the load.
7. Operate the bandswitch manually during initial testing. Do not connect band
decoders, band data lines, or computer interfaces until initial tests are completed
and the amplifier is functioning normally.
8. When using an automatic antenna tuner that has the capability to inhibit the
amplifier from operating either during tuning or when conditions are outside of the
tuner’s capability; and when the Radio Interface Cable that has the Amplifier
Relay line included (not using the RELAY jack); the KEY LINE can be used. The
KEY LOOP Switch is used to route the key signal from the interface to the amp
directly or out the KEY LOOP jack.
a. If the KEY LOOP is not used, set the KEY LOOP Switch to OFF so the
Radio Interface Cable can key the amplifier.
b. If the KEY LOOP is used with an automatic antenna tuner switch the KEY
LOOP Switch to ON, run a cable from the KEY LOOP connector on the

18
amp to the A P ENABLE IN connector on the tuner, and run a cable from
the A P ENABLE OUT connector to the RELAY connector on the amp.
Optional Radio Interface Cables
ALS-1406/ALS-706/ALS-1306/RCS-12 Radio Interface Cables available from
Ameritron.
Model No. Description Notes
DB-13D ICOM with ACC, 13-Pin DIN
DB-7DI ICOM with ACC 2, 7-Pin DIN
DB-DB7DK Kenwood with DB9 (except
TS-480)
SET Baud RATE 9600
TS-590 menu 53 (HF) 54 (50 MHz) #2,
TS-5 0 menu 39 (HF) and 40 (50
MHz)#2
TS-990 s menu 11 (HF) and menu 12 (50
MHz) set to 3= active high+relay+delay
TS-2000 menu 28A #2
DB-DB8MK Kenwood TS-480 Baud rate 9 00, menu 28 (HF) channel 2
and 29 (50 MHz) channel 2
DB-8MY2 Yaesu FT-
897/857/817/840/890/990/100
DB-8DY Yaesu with standard 8-Pin DIN
Band Data
DB-10MY Yaesu FT-450/950/1200
DB-DB15Y Yaesu FT-DX3000
DB-DB15HE Elecraft
Table 2 Optional Radio Interface Cables

19
Operation
This amplifier covers all Amateur Radio frequencies below 54 Hz, as restricted by
FCC or your local governing authority. Once you have established proper connections,
please set the amplifier (Fig. 5, ref 3) to one of the following bands:
Band Frequency
Range
Notes
160 1.8 - 2.2 Hz
80 3.0 - 4.8 Hz
40 4.8 - 9.0 Hz
30 9.0 - 14.5 Hz USA 30 meter power limit currently 200 watts
20 9.0 - 14.5 Hz
17 14.5 - 22.5 Hz
15 14.5 - 22.5 Hz
12 22.0 – 30.0 Hz Amplifier automatically disables above 26 Hz
10 22.0 – 30.0 Hz Amplifier automatically disables below 28 Hz
6 50.0 – 54.0 Hz
Table 3 Band Frequency Limits
Do not operate the amplifier with the band switch on a higher band than the indicated
range. Doing so will cause harmonics that will exceed the FCC limits and cause
interference with Amateur and other services. Do not operate the ALS-1406 in the 6-
eter position on any of the other bands. Damage to the filter board can occur.
Caution: This amplifier has an FCC mandated automatic disconnect and other features
preventing 27 Hz operations. There is no available circuitry or control provision to
circumvent this lockout.
MARS or CAP Operation
For licensed amateur radio operators participating in ilitary Affiliate Radio Systems or
Civil Air Patrol, this amplifier is suitable for use on all frequencies between 1.8 and 54
Hz with some precautions. The upper frequency limits are in bold type in the table
above. Do not operate above the bold-type frequency limits in the table above or PA
(power amplifier) or filter damage may occur.
Ameritron guarantees to exceed FCC Part 97.317 harmonic suppression standards
inside the amateur bands listed in the table above. Ameritron does not guarantee
harmonic suppression or operation outside amateur bands. ost commercial
services prohibit use of non-commercial radio equipment.
This amplifier is inoperable between 26 and 28 Hz. odifications allowing operation
in the 26-28 Hz range is not available, irrespective of licensing or end-use.

20
Initial Operation
For your personal and equipment safety, double-check all wiring and connections (fig.
1) before turning power on. After you have verified amplifier connections, follow the
procedures below. The following steps are necessary during initial checks:
1. Place the MULTIMETER switch (fig.5 ref 7) in the HV2 position. Place the ALC
SET control (fig.5 ref 5) full clockwise (10 on knob scale). The multimeter is the
right-side scale on the rightmost panel meter (fig.5 ref 7).
2. With the STANDBY/OPERATE switch (fig.5 ref 8) on STANDBY, turn the power
switch (ref 9) ON.
3. There will be a slightly delayed “click” from the power supply. HV2 (fig.5, ref 2)
should immediately rise to near full scale, and after another delay, you should
hear another “click”. The meters and the appropriate BAND LED (fig.5, ref 4)
should illuminate.
4. The multimeter HV2 scale (fig.5, ref 2, bottom right scale) should read between
45 and 55 volts.
5. Change the meter switch (fig.5 ref 7) to HV1. The voltage should be the same as
in step 4.
6. Rotate the BAND switch (fig.5 ref 3) through all positions. The appropriate BAND
LED will illuminate, and you should hear band-filter relays switch between 160-
80, 80-40, 40-30, 20-17, 15-12, and 10-6 selector position changes.
7. Set the BAND switch (fig.5 ref 3) to a band where you have a good 50-ohm high-
power load connected.
8. Change the meter switch (fig.5 ref 7) to REF. In this position, the multimeter
indicates reflected power.
9. With no modulation in the F , A , RTTY, or CW mode, and the amplifier still on
standby, adjust your exciter power to about ten watts. This is to have a steady
unmodulated carrier. Verify you have very low power, ideally around 10 watts
carrier (not critical), and that VSWR of the antenna system is low. You should
see almost no deflection on the reflected power scale (fig.5 ref 2) with the
MULTIMETER switch in the REF position. If you see reflected power deflection,
check your RF cables and antenna system. Reminder: You cannot use a tuner
in your radio, or between your radio and this amplifier, to match the
antenna system. Any antenna matching must be between the amplifier and
the antenna, and the antenna tuner and other items beyond the amplifier
must be conservatively able to handle over 1200 watts of carrier or pea
envelope power.
10. Place the amplifier in OPERATE position (fig.5 ref 8). Be sure the BAND on the
amplifier matches the band selected on the transceiver.
11. Place the transmitter or transceiver into transmit in F , A , RTTY, or CW
modes. The green TX LED (fig.5 ref 6) should light. The forward power (fig.5 ref
2) should increase to approximately ten times the initial exciter power reading.
Reflected power should remain very low, and the PA current should increase
slightly on both scales of the current meter (fig.5 ref 1). No other LED’s should
illuminate.