Alpha Radio Products 8410 Operating Manual
ALPHA 8410
HF LINEAR AMPLIFIER
OPERATING MANUAL
© 2009 Alpha Radio Products, Inc
Specifications subject to change without notice - Rev. 102
6185 Arapahoe Ave.
Boulder, Colorado 80303
Phone 303 4739232
All rights reserved
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Serial Number ______________________
Date Shipped _______________________
Software Version ____________________
Order Number ______________________
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Index
Specifications 4
Introduction 5
Quick Start Information 9
Station Engineering Considerations 11
Unpacking and Preparation 15
Theory of Operation 23
Operation and Maintenance 27
Trouble Shooting Hints 39
Glossary 43
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Specifications
Frequency 1.8-29.7 KHz
Input drive Level 50 Watts Nominal
Power Output 1500 watts
SWR Tolerance 3:1
Duty Cycle 100 %
Tubes 2x VTX-X118 Alpha, (4CX1000A)
Inter Modulation Level 30 dB minimum, Two Exciter
Harmonics -50 dBc
Mode of Operation CW, SSB, FM
Input AC Voltage 100-240 Selectable
AC Current <13 5mps @240 VAC @1500 watts
Input Impedance 50 Ohms
Output Impedance 50 Ohms
RF Connectors SO-239
Cooling Forced Air
Size 17.3 W x 7H x 21.0D Including Fan
Space
Weight 70 lbs., 31.8 kg
T/R Relay Vacuum QSK
Tuning /Band switching Manual
Display Bargraph LED
Interface USB
Protection Against all common faults
RF Bypass Level Less than 500 watts
This amplifier meets or exceeds all technical specifications listed above.
Technician ____________________________ Date ____________________
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1 Introduction
1.1 General Description
Congratulations on your purchase of a professional quality Alpha 8410 amplifier! With
proper installation and care, you can expect to enjoy your Amateur Radio hobby with this
amplifier improving your signal for many years to come. Please study this manual
carefully before operating your amplifier for the first time.
The Alpha 8410 is a self-contained manual tune HF linear power amplifier capable of
continuous operation at 1500 W peak power output on SSB, keyed CW, SSTV, RTTY,
digital modes or FM, with no time limit.
Other Alpha products available to enhance your use and enjoyment of the 8410 amplifier
include:
Alpha 2100 full 1500-watt rated 50-ohm dummy loads and
Alpha 4500 series SWR meters / Wattmeter
See our web site at www.alpharadioproducts.com or call 303-473-9232 for further
information.
1.2 Amplifier Capabilities
CAUTION:
It is extremely important to thoroughly review the Installation and
Operation sections of this manual before attempting to us the Alpha
8410. Failure to do so could result in serious damage that may not be
covered under warranty.
Continuous RF Output. The 8410 is capable of 1.5 kW continuous RF output on
all commonly used modes and on any authorized amateur frequency from 1.8 to
29.7 MHz.
Compatibility with popular amateur transceivers and exciters. The 8410 requires
approximately 50-65 W peak RF drive for 1.5 kW output.
Capable of full CW break-in, QSK and all digital modes when used with any
appropriate transceiver.
Protective functions are built in. The control system incorporates protective
functions that minimize the probability of accidental damage to the amplifier or
its power tubes. In most cases, when one of the protective functions is “tripped,”
the amplifier will go to Standby.
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1.3 Shipping Information
The Alpha 8410 amplifier ships in two heavy-duty cardboard cartons. One carton holds
the power transformer and weighs 43 lb (20 kg) and the second carton contains the
amplifier and weighs 38 lb.(17 kg). Both of these cartons are mounted on a wooden pallet
and strapped down for a total weight of 98 lb.(45 kg).
Alpha recommends that you retain the pallet and the cartons after installation in the
unlikely situation that you need to ship the unit later. Contact Alpha at 303-473-9232
for shipping advice and assistance.
1.4 Safety Information Installation and Operation
Make sure the Alpha 8410 is located where there is good air circulation all around
and on top of the cabinet. The unit may become hot during operation.
The Alpha 8410 weighs approximately 70 pounds when the transformer is
installed. Use proper lifting techniques and two people when moving the
amplifier. Note that amplifier should NEVER be transported with the transformer
in place.
The Alpha 8410 is designed to meet international safety standards and FCC
regulations. However, one should always remember that the equipment works
with high voltages that can be LETHAL!
This operating manual holds information, cautions and warnings that must
be followed to ensure safe installation and operation. Read Chapter 1
before attempting to unpack or operate the Alpha 8410 amplifier.
Warnings: What Not to Do
Never open the amplifier case without unplugging the unit from
the wall outlet.
Always resist the temptation to immediately hit the ON button after
the amplifier faults to power off.
Never touch an antenna during transmission.
Never attempt to turn on the amplifier without the cover
securely in place (all attachment screws reinserted).
Never turn the amplifier back on after a hard fault without
waiting at least 20 seconds.
Never allow liquids to enter the amplifier through the cover holes.
Never stick objects into holes in the case.
Warnings posted in this manual should be read and thoroughly
understood by users. Failure to perform procedures properly may
result in amplifier damage, fire hazard, or electric shock.
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1.5 Owner Assistance
Technical Assistance from Alpha Radio Products is available from several sources.
The Alpha Radio Products web site is www.alpharadioproducts.com. Click
on Support and follow the instructions. Many typical problems and their
solutions are listed on this site. On this site you can get the following
assistance:
Technical Support
Repair Information
Software Downloads
Manuals
Tech Tips
Legacy Equipment Information
FAQ’s
Alpha Forum
You can email us for customer support at service@alpharadioproducts.com or
you can send your request by fax to 303-473-9660, or call us at 303-4739232
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2 Quick Start Information
2.1 Overview
This section explains in brief the items you need to consider when setting up your
Alpha 8410 amplifier.
If you already have a well-designed shack and have used an amplifier before, please
review the items below to make sure you have considered all the critical items for
proper installation and operation.
If you are using an amplifier for the first time, please skip this section and go to sections
3, 4, and 5 for a more detailed explanation of how to set up your shack for maximum
safety and operating enjoyment.
If you have installation questions, do not hesitate to contact Customer Support. We
much prefer to address questions prior to power up.
2.2 Station Engineering Considerations - Checklist
Make sure you have properly addressed the following concerns (Section 2.3 below)
before installation of your Alpha 8410 amplifier. If you are unsure of any of these
items, please read the noted sections carefully.
2.3 Preparation
__ 240V AC Power in shack? (Section 3.2)
__ Amplifier placed with proper airflow? (Section 3.3)
__ Antenna ready for 1,500W? (Section 3.4)
__ Adequate RF cabling? (Section 3.5)
2.4 Unpacking
__ Unit Checked for Damage?
__ Transformer Installed? (Section 4.2.1, 4.2.2)
__ Power Cord Connector Attached? (Section 4.2.3)
__ AC Primary Voltage Set? (Section 4.3.6)
___Amplifier Grounded Properly? (Section 4.4.1)
__ Amplifier Cover Replaced and Secured? (Section 4.3.6)
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2.5 Operation
__ All Exciter Interconnections Set? (Section 6.2)
__ Exciter Drive Correctly Set? (Section 6.1.1)
__ Amplifier Tuned to Antenna System? (Section 6.3.6)
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3 Station Engineering Considerations
3.1 Overview
The Alpha 8410 is capable of dramatically improving the performance of your amateur
station. It is important that you observe good engineering practices to achieve all the
benefits of such a station in a safe and reliable manner. This section provides a few
hints for important operational considerations, but it is recommended that the user also
consult a good source of general information such as “The Radio Amateur’s
Handbook” by the ARRL, especially if this is the first high-power amplifier you have
used.
3.2 AC Power Source
This amplifier runs best when powered by a 200V - 240V AC circuit. If you do not have
a 240V AC outlet in your shack, you will need to get a licensed electrical contractor to
install one. A minimum of a 20 amp capacity is required. A 20 amp breaker on your
240V circuit is sufficient. There are many styles of plugs, some of which are countryspecific. For this reason, the amplifier is not shipped with a power plug. Select a
location for the outlet as close as possible to where you expect to operate the 8410. If
you are not sure, or contemplate moving the amplifier, you may choose to get a second
outlet installed at the same time. Ask your contractor for two or three matching plugs
during installation as there are several styles of connector available. Ask the contractor
to measure the voltage and record it, so you can set the line voltage tap on the 8410
appropriately. If possible, have the contractor measure the line voltage with a 10 amp
current draw, and use this value for setting the transformer tap. The Alpha 8410 can run
when connected to an 120V AC outlet. However, you WILL NOT achieve full legal
limit output in this case. If the amplifier is connected to an 120V AC outlet, you should
not expect more than 1000 W output.
3.3 Air Flow
It is critical that airflow around the Alpha 8410 remain unimpeded at all times. Keep the
top of the amplifier clear of any restrictions. If you are mounting the amplifier in a
console, make sure that the exhaust air is properly and fully removed from the console.
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Figure 3.3 -Minimum clearance for proper airflow
Keep top tube exhaust clear
Keep rear intake clear
Make sure the exhausted air
cannot be recirculated back
into the amplifier air intake.
Too ensure adequate cooling,
make sure the top and rear of
your amplifier have at least 3”
of clearance to allow
unobstructed airflow.
Poorly designed consoles can result in outlet air being drawn back into the amplifier air
intake and recirculated, thus getting hotter and hotter and resulting in degraded amplifier
performance or even failure. If you are designing your own console, consider putting in
additional fans and/or ducting to deal with waste heat. Try to minimize the possibility of
dust or other contamination getting drawn into or falling on the amplifier. It is also
advisable to periodically (at least annually) clean the dust out of your amplifier for
continued flawless operation. Alpha Radio Products recommends the use of compressed
air for dust removal.
3.4 Antennas
Many antennas that are suitable for general use are unsuited for operation with a full
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1500 W of power. At this power level in a 50-ohm circuit, the RMS current is 5.5 amps
and the peak RF voltage is 387 volts. With a 2:1 SWR, these values double to 11 amps
and 775 volts. The actual voltage and current at various points in or on your antenna may
actually be many times these values. On a simple dipole with sharp wire ends, corona
(localized ionization) can easily occur. Corona can (and has!) led to fire in nearby
objects. Traps in beams and verticals can heat up significantly during high power
operation. Instances of melting or flashover of traps have occurred in many installations
where insufficient thought has been given to their ratings. If an antenna has been
deployed for a long period of time, it may be worth taking it down for inspection prior to
full power operation. If any insulators are cracked or show signs of “tracking”, in this
part of the band.
3.5 Coax and Connectors
The importance of a well-constructed feed-line system cannot be overstated. After all, the
purpose of the amplifier is to provide approximately 2 S units (12+ dB) of improvement
in your radiated signal. All too often, installation problems are encountered where cheap,
poor or under-rated coax and connectors are used. These often are responsible for at least
one S unit of degradation. (This means you could have bought a 375 W amplifier and
achieved the same radiated signal by buying good quality feed-line components!) Use
the lowest loss 50-ohm coaxial cable you can obtain. Use new, clean connectors installed
according to the manufacturer’s recommendation. Clean the connectors after soldering
them, and before mating them with the amplifier. Make sure any excess solder is
removed from the connector; likewise remove any fragments of braid etc. Never use old
coax, which may have had moisture penetrate under the jacket. Support the coax
frequently using non-compressive clips so that it does not hang or stretch under its own
weight. Avoid sharp or kinked bends (most manufacturers will specify a minimum bend
radius for their product). Make sure the connection from feed-line to antenna is
waterproof. Provide for disconnection of the feed-line when it is not in use; this protects
against damage caused by power surges and lightning strikes, which are not covered
under the amplifier warranty.
3.6 RF Safety
The FCC requires users to check their installations for compliance with published values
for allowable exposure to RF fields. This information is available in ARRL publications,
FCC printed rules, and on the web. Alpha Radio Products strongly recommends that this
be done for any installation, both fixed and at an expedition or contest site.
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If you have any questions regarding engineering your 8410 into your amateur radio
station, please visit our online technical support website at:
www.alpharadioproducts.com
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