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Operating Manual
Information in this document is subject to change without
notice. Information provided by Alpha Radio Products Inc.®
is believed to be correct and reliable. However, no
responsibility is assumed by Alpha Radio Products, LLC.,
unless otherwise expressly taken. Companies, names, and
data used as examples are fictitious, unless otherwise noted.
No part of this document may be reproduced or transmitted
in any form or by any means, graphic, electronic, or
mechanical, for any purpose without the express permission
of Alpha Radio Products, Inc. Alpha Radio Products, Inc.
may have patents or pending patents, trademarks,
copyrights, or other property rights covering the subject
matter in this document. The furnishings of this document
does not give you license to these patents, trademarks,
copyrights, or other intellectual property, except as expressly
written in any license agreement form
Alpha Radio Products
6185 Arapahoe Road • Boulder, CO 80303
Phone 303.473.9232 • Fax 303.473.9660
Read this entire manual and all other publications pertaining
to the work to be performed before you install, operate, or
maintain this equipment. Practice all product safety
instructions and precautions. Alpha Radio Products, LLC.
provides information on its products and associated hazards,
but it assumes no responsibility for the after-sale operation of
the equipment or the safety practices of the Owner or User.
See Warranty and Notices Appendix.
©Copyright 2005 by Alpha Radio Products, LLC.
All rights reserved.
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Alpha 87A User Manual Rev 2.0
Table of Contents
Owner Assistance
Equipment Shipped
Protective Functions and “Faults”
Safety: Installation and Operation
Soft Faults
Before Installing Your Alpha 87A
Hard Faults
Before Operating Your Alpha 87A
Fault Codes
Overview of Amplifier Capabilities
RS-232 Serial Communications Link
ALPHA 87A Specifications
Communications Link Set-up
Figures 1-3 Transformer Installation
Serial control lines
Unpacking and Preparing for Operation
Remote Commands
Figure 4 – Inside Top View
Troubleshooting Suggestions
Figure 5 – Front Panel Lowered
Owner Assistance
Figure 6 - Inside Front Panel
Overdrive related faults
Control and Indicator Functions
Repeated power-off shutdowns
ALPHA 87A Functional Configuration
AlphaMax Operating Procedures
Principal Functional Components
Schematic Description
Schematics Available
AlphaRemote Operating Procedures
Installing the AlphaRemote Software
How to Operate the 87A
Step-by-step Procedure
Pre-Tuning Procedure
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Alpha 87A User Manual Rev 2.0
The Alpha 87A is a self-contained HF linear amplifier. It provides continuous maximum-legal-power
on all amateur HF bands with self-tune capability.
This manual provides all information necessary to install and operate the ALPHA 87A. Schematic
diagrams are available on request, at no charge to owners.
Owner Assistance
Assistance is available from Alpha Radio Products at 303.473.9232 x.141, by fax at 303.473.9660,
or by email at [email protected]
Equipment Shipped
The Alpha 87A ships in two heavy-duty cardboard cartons. One carton holds the power transformer
and weighs 43 pounds; the second carton contains the amplifier and weighs 42 pounds.
Safety: Installation and Operation
The Alpha 87A is designed to meet international safety standards and FCC regulations. However, one
should always remember that the equipment works with high voltages that are LETHAL!
This operating manual holds information, cautions and warnings that must be followed to ensure safe
installation and operation. Read Section 1 before attempting to unpack or operate the amplifier. Failure
to perform procedures properly may result in amplifier damage, fire hazard, or electric shock.
Never open the amplifier case without unplugging the unit from the wall outlet.
Never stick objects into holes in the case.
Never touch an antenna during transmission.
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Alpha 87A User Manual Rev 2.0
The ALPHA 87A is extremely easy to install and operate, but failure to carry out each
procedure exactly as described in the manual is likely to lead to amplifier damage, which is
not covered under warranty. Damage to other station equipment may also result.
Before Installing Your Alpha 87A
1. Be careful not to twist or warp the chassis
when handling the amplifier with its cover
removed. Never lift the chassis by a
corner, especially when the transformer
is in place. Never apply AC power
without the transformer properly and fully
6. Solidly bond all station equipment
chassis together. Heavy braid, such as
the outer conductor of RG-8/U coaxial
cable, is recommended for the purpose.
This is important for personal and
equipment safety as well as to avoid RF
2. When installing or removing the
transformer, move carefully and follow
the instructions in this manual exactly.
Insure that all connectors are properly
mated and fully seated. Don’t force
them! Tuck the lifting handle out of the
way so the interlock can close.
7. Never install cover screws longer than
¼”. Longer screws may penetrate
internal boards or wiring and cause
severe damage. Make sure each screw
hole in the cover is aligned with its
corresponding captive nut in the chassis
before inserting screws.
3. Insure that both tubes are solidly seated
in their sockets with the red silicone
rubber chimneys firmly seated against
the chassis.
4. Connect the green conductor in the
Alpha 87A power cord only to the power
source neutral or ground. Connecting
the green wire to a “hot” line is almost
certain to cause immediate damage.
Triple checks your wiring before plugging
5. Make sure the primary power tap is
connected to the tap closest to your
actual AC voltage. See manual section
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Alpha 87A User Manual Rev 2.0
Station Engineering Considerations
The 87A 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 gives a few hints for important things to look for, 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.
AC power Source If you do not have a 220V 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. Select a location for
the outlet as close as possible to where you expect
to operate the 87A. If you are not sure, or
contemplate moving the amplifier, it may be
cheaper to get a second outlet installed at the
same time. Ask your contractor for two or three
matching plugs while he is there, 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 87A
appropriately. If he can, ask him to tell you the line
voltage with a 10 amp current draw, and use this
value for setting the transformer tap.
Antenna Many antennas that are suitable for
general use are unsuited for operation with a full
1500 watts 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: 11 amps and 775 volts. The
voltage and current at various points in or on your
antenna can actually be many times these values.
On a simple dipole with sharp wire ends, corona
(localized ionization) can easily occur. Corona can
(and has!) lead 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
up 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”, replace them.
Doubling-up on insulators is also easy to do,
and may save problems. If there is any
chance of people or object coming close to
the antenna, take steps to move it higher, or
place barriers so that this cannot happen.
Check the SWR of your antenna. If you have
a favorite part of any band you use most
often, consider adjusting the antenna for
minimum SWR in this part of the band.
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 (coax and connectors
continued) approximately 2 S units (12+ dB)
of improvement in your radiated signal. All too
often installations are encountered where
connectors are probably responsible for one S
unit of degradation. This means you could
have bought a 375watt amplifier and achieved
the same radiated signal by buying good
quality feed line components! Use the lowest
loss 50 ohm coaxial cable you can get your
hands on. Use new, clean connectors Clean
the connectors after soldering them, and
before mating them with the amplifier. Make
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Alpha 87A User Manual Rev 2.0
sure any excess solder is removed from the
connector, likewise any fragments of braid etc.
Never use old coax, which may have had moisture
penetrate under the jacket. Run the coax in straight
lines as much as possible. Support it frequently
using non-compressive clips so it does not hang
and stretch under its own weight. Avoid sharp
bends (most manufacturers will specify a minimum
bend radius for their product). Make sure the
transition from feed line to antenna is waterproof.
Provide for disconnection of the feed line when not
in use.
Air Flow It is critical that the 87A airflow is
unrestricted in any way. 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. Poorly designed consoles can result in
outlet air being drawn back into the amplifier air
intake and recirculated, getting hotter and hotter,
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.
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.
If you have any questions regarding engineering
your 87A into your amateur radio station, do not
hesitate to call Alpha Technical Support. Installed
per the manufacturers recommendations.
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Alpha 87A User Manual Rev 2.0
The ALPHA 87A is extremely easy to install and operate, but failure to carry out
each procedure exactly as described in the manual is likely to lead to amplifier damage which
is not covered under warranty. Damage to other station equipment also may result.
Before Operating Your Alpha 87A
1. You must set transceiver power output properly.
The Alpha 87A requires about 50 watts drive for
full rated output.
Damage caused by
overdriving the ALPHA 87A will not be
covered under warranty. Fortunately, most
modern transceivers maintain quite consistent
output from band to band and mode-to-mode if
set up properly. We recommend that you only
run the Alpha 87A in high voltage mode, running
your amp in low voltage mode with high plate
current can damage components.
Setting the transceiver POWER or RF PWR
control IS NOT SUFFICIENT. Several popular
transceivers can generate RF spikes of 200300W or more unless the transceiver internal
ALC (drive level) is also adjusted carefully
according to its manufacturer’s instructions. This
typically is done with a knob labeled DRIVE (IC781, FT-1000), PROCESSOR OUT (TS-940, TS950) or, on SSB when speech processing is not
in use, MIC or MIKE.
2. The ALPHA 87A “faults” into STBY or OFF
when unsafe operating conditions occur. If
this happens, record which SEGMENT LEDs are
flashing to indicate a BCD fault number, and refer
to manual section 8.0.
3. On any frequency where your antenna
VSWR exceeds 1.5:1, it’s important to
manually program the ALPHA 87A for a
proper match. See manual sections 7.27.4. Efficiency, linearity, and output often
can be improved even when VSWR is
less than 1.5:1. The 87A does not
contain an antenna tuner. The SWR will
need to be tuned via the antenna or an
external tuner connected to the output of
the Alpha 87A.
after manually tuning your ALPHA 87A in
any given segment, first press ENTER;
then, while the ENTER LED is flashing,
press the desired SEGMENT button.
4. To operate the ALPHA 87A efficiently
and cleanly at power output much
different from 1.5kW it must be manually
tuned and loaded (i.e. programmed)
accordingly or AlphaMax must be turned
on. See Section 7.
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Alpha 87A User Manual Rev 2.0
5. Induced energy from nearby electrical
storms or other power transients may
damage components. Such damage is not
covered under warranty. It is important to
use a good lightning arrestor, and it is good
practice to disconnect and ground antenna
feed lines, and to disconnect A-C power,
when the equipment is not in use.
6. Never use an automatic antenna tuner into or
through the Alpha 87A. This will cause
damage to the input wattmeter & input relay.
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Alpha 87A User Manual Rev 2.0
Overview of Amplifier
It is extremely important to thoroughly review the Installation and Operation sections of this manual
before attempting to use the ALPHA 87A. Failure to do so could result in serious damage not covered
under warranty.
Continuous RF Output. The Alpha 87A
is capable of 1.5kW continuous RF
output on all commonly used modes and
on any authorized amateur frequency
from 1.8 to 29.7 MHz. Band change
and tune-up are microprocessor
controlled and no special cables or
adapters are required.
Compatibility with popular amateur
transceiver and exciters. The Alpha 87A
requires approximately 50-55 watts peak
RF drive for 1.5kW output. No user
programming or adjustments are
necessary for maximum-legal-power
amateur operation into load VSWRs as
high as 1.5:1. However, the amplifier
may easily be user-programmed to
optimize operation with VSWRs up to
2:1, on non-amateur frequencies, and
at various power levels.
Capable of full CW break-in (QSK) and
all digital modes when used with any
appropriate transceiver. All front panel
functions plus numerous other
diagnostic and control functions are
communications port.
Protective functions built in.
microprocessor-based 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,” front
panel LED indicators display a fault
code, which indicates the nature of
the problem, (e.g. excessive grid or
plate current, load VSWR, etc.)
AlphaMax firmware comes with added
features to readjust output network, trim
tune-up time, and re-adjust loading to
prevent distortion due to overdrive.
AlphaRemote software lets you to control
all functions of your Alpha 87A from a
compact toolbar on your Windows
Optional auxiliary cooling fan available.
We recommend using the external
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Alpha 87A User Manual Rev 2.0
auxiliary fan for extended RTTY or other
“locked key” service. This is available
separately from Alpha Radio Products.
Capable of no more than 150 watts into a
50dB load in bypass mode.
Page 10
Alpha 87A User Manual Rev 2.0
ALPHA 87A Specifications
FCC rules do not permit new amateur amplifiers to be operable on 24-30 MHz as delivered
within the US and possessions. Owners who send Alpha Technical Support a photocopy of
their authorizing amateur license will promptly be provided information on “unlocking” 12 and
10 meter coverage..
Band Change & Tuning: Automatic under
microprocessor control; average time required for
complete band change and tune-up, <1 second.
No special cables or connections required.
Frequency Coverage: All amateur bands 1.8-29.7
MHz* plus most non-amateur frequencies 6.0-19.0
MHz and 20-30 MHz.
Power Output: 1500 watts PEP, keyed CW, or
continuous carrier, no time limit. Auxiliary cooling
fan (optional) recommended for very high duty
cycle continuous operation i.e. contesting & RTTY.
Drive Power: Typically 50 to 55 watts for full rated
Input VSWR: < 1.5:1 within amateur bands; < 2:1
Tube Complement: Two Eimac 3CX800A7
triodes in grounded grid.
T/R System: Heavy-duty PIN diode switch capable
of feed through and hot switching of 150W exciter
Switching time approximately 1ms.
Enclosed mechanical bypass relay.
Grid-current-derived, -10V maximum,
adjustable gain.
Harmonic Output: Better than 50 dB below rated
Intermodualtion: Better than 35 dB below rated
Fault Protection: Plate current, grid current, load
VSWR, T/R sequencing, gain (i.e., severe mistune
or RF arc), overdrive, open heater, over
temperature, others.
Displays: LED bar graphs for peak Pout, Prefl & Ig,
and switched bar graph for Ip, HV, and Tune
Cooling: Full cabinet ducted air, rear intake/top
exhaust. Floating blower mount for quietest
Primary Power: 190-250V (200, 220, 240V
nominal taps), 50-60 Hz, single phase; fused 20A.
Size & Weight: 17.3” W x 7”H x 16.5” D (439 x
178 x 419 mm) excluding controls, feet, and
connectors. 75 lb. (34kg) net.
Note: Alpha Radio Products reserves the right to
change design and/or specifications without prior
notice or obligation.
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Alpha 87A User Manual Rev 2.0
Figures 1-3 Transformer
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Alpha 87A User Manual Rev 2.0
Unpacking and Preparing for
(Refer to Figures. 1-5, pages 6, 8, 9)
4.1 Carefully unpack amplifier and
Inspect both for physical
damage. Save all packing material for future
tap (200, 220, or 240V) closest to your
nominal AC line voltage. (Amplifiers for US
distribution destinations normally are shipped
connected for 240V input.)
4.2 Remove cover by removing all screws
except the two located in the perforated tube
exhaust areas. Inspect carefully for shipping
damage. Check all connectors for proper
seating. If damage is discovered, call Alpha
Technical Support immediately.
4.3 Remove blower motor shipping hardware
from rear chassis wall. Save the two 10-32
bolts, fiber washers, and rubber shim; reinstall
this hardware whenever the chassis is
transported. NOTE: For heavy-duty use or
50 Hz operation, the optional auxiliary fan
must be installed.
4.4 Connect the proper internal line voltage
tap. The ALPHA 87A may be operated from
any AC power source of 190-250V, 50-60 Hz,
20-ampere capacity. It is advisable to check
the actual voltage at the connector you are
going to use for the Alpha 87A. Use an
accurate meter such as a DMM set to AC
A 4-terminal barrier strip for tap
selection is located atop the AC module to the
left of the transformer, approximately where
the arrow points in fig. 1A. DO NOT MOVE
the wire connected to the terminal marked
PRI! If necessary, move the other wire to the
4.5 Install Transformer. Position amplifier flat
on a table with the right side of the chassis
facing forward. Install the transformer per
Figures 1 through 3, using its wire handle.
Use care not to damage wiring or
Page 13
Alpha 87A User Manual Rev 2.0
components. You may wish to have a helper
steady the chassis during the following two
steps. (Bolts must be installed for safe
Align the transformer captive nuts with
corresponding chassis holes. Taking care not
to torque or twist the chassis, carefully extend
it over the edge of the table just far enough to
loosely screw in the two outside transformermounting bolts (1/4-20 hex head with flat
washers, supplied).
Do not stand the amplifier on edge or move it
further over the table edge. Instead, rotate it
so as to install the bolts. Now center the
transformer as much as possible so that both
sides are well clear of metalwork. Move
chassis as above while tightening all 4 bolts.
Inspect the connectors on the transformer to
be sure there is nothing blocking the
connector holes, such as pieces of shipping
One of the transformer’s
connectors plugs into the AC power module
near the top/rear of the chassis center
partition, on the power supply side. Another
connector plugs into the low voltage power
supply board, which is immediately in front of
the transformer near the chassis floor.
A third (HVAC) connector plugs into the HV
board in front of the transformer and up high.
(See Fig. 3 and views A-A and B-B). Make
certain the connectors are properly mated and
seated, but don’t force them; they mate and
latch easily.
4.6 Insure that both tubes are fully seated in
their sockets with their red rubber chimneys
firmly contacting the chassis.
4.7 Make sure the HV crowbar works
4.8 Replace the cover and carefully
reinstall all screws. Be careful not to force
or cross thread the screws. Never use
screws longer than ¼”! (Screws supplied are
Do not attempt to operate the amplifier with
the cover removed. This could cause
damage to the Alpha 87A or you.
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Alpha 87A User Manual Rev 2.0
Figure 4 – Inside Top View
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Alpha 87A User Manual Rev 2.0
Figure 5 – Front Panel
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Alpha 87A User Manual Rev 2.0
Figure 6 - Inside Front
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Alpha 87A User Manual Rev 2.0
Figure 7 - Rear Panel
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Alpha 87A User Manual Rev 2.0
Control and Indicator
REFLECTED POWER bargraphs are peakreading and generally self-explanatory.
Example: 1.5 kW output (forward power into
a 50 ohm load) is indicated when all green
LED segments to the left of the 1.5 (kW) label
are fully lighted and the first red LED segment
is barely illuminated. The primary calibration
point for RF OUTPUT is at 1.5 kW on 14
MHz. Accuracy of the meter is approximately
5.2 TUNE/IP/HV “multimeter”: The function
of this indicator is selected by buttons at its
right. It is a moving-dot display. HV (plate
voltage) is read on the 0-3 kV top scale and Ip
(plate current) on the 0-1.5 A bottom scale.
The TUNE meter function permits fast and
safe manual tuning and loading of the
amplifier at reduced power (Sec. 7.3)
87A automatically switches bands and tunes
up, if necessary, upon application of RF drive.
BAND and SEGMENT buttons may, however,
be used before applying drive to avoid the
brief amplifier bypass, which occurs during
automatic band change with drive applied.
When a new BAND is selected manually, the
amplifier automatically selects the segment
last used on that band unless a different
SEGMENT button is pushed. To protect
against improper tuning, the ALPHA 87A
automatically overrides any improper manual
band or segment selection upon application of
The SEGMENT buttons and the row of
buttons below them also are used in field
programming of the ALPHA 87A as
described later.
5.3 BAND and SEGMENT buttons: Each
band (tuning range) is represented by a
button with indicator LED on the upper left
front panel. On each band, five memory
channels, or segments, are provided for
factory programmed tuning data and five for
user (field) programmed data. On the front
panel, five SEGMENT buttons with LED
indicators correspond to these band
segments as detailed below.
Each BAND button is labeled with the nominal
(MHz) frequency of the principal amateur
band covered within its tuning range.
Labeling below each SEGMENT button
indicates its factory programmed frequency
coverage relative to the frequency in MHz
shown below the BAND button. As may be
deduced, on all bands except 1.8 and 28 MHz
segment center frequencies are factory turned
at 100 kHz spacing; 1.8 MHz segments are
spaced 40 kHz, 28MHz segments 400 kHz.
BAND or SEGMENT buttons are not used
during routine operation because the ALPHA
5.5 Factory Programming: Each segment is
factory (default) programmed so that the
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Alpha 87A User Manual Rev 2.0
ALPHA 87A will deliver 1.5 kW output (into a
50-ohm load of VSWR of <1.5:1) efficiently
across the frequency range indicated under
that SEGMENT button.
Example: Using default (factory) tuning with
the “14” (BAND, MHz) button and the number
3 SEGMENT button illuminated, ALPHA 87A
tuning is centered at 14.250 MHz for optimum
performance from approximately 14.2 to 14.3
MHz. Panel labeling shows the nominal
edges of factory segments in the 1.8 and 28
MHz bands. Actual segment coverages
overlap somewhat to prevent “hunting”.
KEY OUT – Provides a pull-down to ground
(through 47 ohm resistor) which follows the
line connected to the RELAY jack when the
amplifier is ON and in OPERATE condition.
When the 87A is in STANDBY or OFF, KEY
OUT is directly connected to the RELAY jack
by a closed relay contact I the amplifier.
Useful for special T/R hook-ups when
amplifier is used with exciters having poor T/R
sequencing. Contact Alpha Power Customer
Support for specific advice.
J1-RS-232 communications link; see Section
9.Figure 7 Rear Panel Connections
5.6 User Programming, TUNE & LOAD
buttons: The ALPHA 87A may be user-tuned
at any five different center frequencies in each
band; the five SEGMENT buttons may be
assigned to these frequencies in any desired
order, as explained in Section 7.2. The TUNE
and LOAD buttons are used during user
Each segment is identified in memory by its
center frequency and nominal width. During
automatic segment selection the amplifier
seeks first the nearest user segment centered
within 50 kHz of the drive frequency (10M,
+200 kHz) then such a factory segment. If
neither exists it selects the nearest segment.
5.7 DEFAULT button: May be used to
override automatically selected user tuneup
data for a segment and instead “default” to
factory data.
5.8 ENTER button: Used in conjunction with
SEGMENT buttons to memorize user-tuning
data. (See Section 7.)
5.9 Special rear-panel connections: (See
figure 7, opposite)
ALC & ALC Adjust – See sections 7.1 & 10.2.
IG & PFWD – Provide d-c signal outputs
proportional to grid current and power output,
Page 20
Alpha 87A User Manual Rev 2.0
(Refer to Fig. 7, page 20)
6.1 Coaxial Cable Types & Connectors
Connect the transceiver RF output to the
ALPHA 87A RF INPUT with 50 ohm coaxial
cable – RG-58C/U or equivalent. A 6 ft. cable
is supplied for this purpose.
Coaxial cable from the Alpha 87A RF
OUTPUT to antenna should be RG-8A/U,
RG-213/U, or equivalent high quality type with
a PL-259 UHF-type plug on the amplifier end.
RG8X cable is not recommended.
6.2 T/R Control Cable
The 87A has a full break-in PIN diode QSK
system requiring only the normal
interconnection when used with a modern
QSK transceiver. The Alpha 87A requires a
contact closure (short circuit) on transmit from
its RELAY jack center pin to chassis. This
function is supplied by the transceiver, usually
from a dedicated relay that is open in receive
and closed in transmit. Shielded wire should
be used for the T/R control cable. The Alpha
87A end must be fitted with a common phono
(RCA-type) plug and the other end with a
connector suitable for the transceiver. See
connections. The voltage at the relay jack is
5V at 1mA; this is acceptable for most modern
The T/R relay contact must close before
application of RF drive. 87A protection
circuitry prevents “hot-switching” with RF drive
applied. Modern transceivers have the proper
time delay between key-up and the start of the
transmitted signal to allow the Alpha 87A to
follow the CW keying. If a T/R timing problem
is suspected, connect the CW keyer to the
RELAY jack on the 87A, and connect a cable
from KEY OUT on the 87A to the keying input
of the transmitter.
6.3 Antenna
Connect a nominal 50 ohm antenna of VSWR
<2:1 at the frequency to be used to the 87A
6.4 Ground Wire
Connect a heavy copper strap or braid from
the #10 ground stud & wing nut on the rear
panel of the 87A to the chassis of the
transceiver and other station equipment, and
to the main station RF ground.
6.5 Green Wire
Connect to A-C power consistent with tap
selected. CAUTION: Be sure the 87A
green wire connects to A-C ground or
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Alpha 87A User Manual Rev 2.0
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Alpha 87A User Manual Rev 2.0
AlphaMax is new firmware designed to add
new features to the Alpha 87A. All amplifiers
shipped after October 1999 have AlphMax
already installed. If you have a amplifier that
was shipped from the factory prior to October
1999, the installation of new chips on the 87A
controller board is required. The chips to be
replaced are in sockets, but if you are not
completely comfortable with opening your 87A
and installing new chips, then please call Alpha
Customer Support for telephone support or for
a Return Authorization. Alpha Customer
Support will install and test the new firmware at
no charge other than the 2-way shipping
As you transmit, AlphaMax automatically readjusts your 87A’s output network to deliver
maximum power output (within maximum
capabilities of the ALPHA 87A) and linearity for
the specific antenna and frequency actually in
AlphaMax even prevents distortion due to
overdrive. If peak RF input to your 87A changes
significantly,* AlphaMax detects the onset of
non-linearity. It quickly re-adjusts loading and
tuning to avert flattopping and splatter - while
maximizing power output. No other amplifier,
vacuum tube or solid state, can do
AlphaMax Operating
The AlphaMax firmware upgrade enables the
Alpha 87A to automatically optimize itself for
changes in drive level, or antenna impedance.
This allows the amplifier to re-tune as the
operating frequency is changed and allows
the amplifier to re-tune if different antennas
are selected. This dynamic adjustment of the
tune and load controls helps to provide
optimum tuning of the 87A to improve
efficiency and reduce the change of distortion.
The classical approach for autotune utilizes a
phase detector but AlphaMax uses artificial
intelligence to readjust the tune and load
controls to optimize the output power while
reducing the grid current and plate currents.
This approach was chosen to enable the large
number of Alpha 87As already in operation to
be upgraded without the expensive addition of
a phase detector and other associated
The software emulates the way a human
operator would monitor an amplifier and
readjust it for optimum performance under
varying conditions. The firmware constantly
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Alpha 87A User Manual Rev 2.0
monitors the various operating parameters and
changes the tune and load controls in response
to varying levels of drive and load impedance.
starting point for the algorithms to find an
optimized value in situations where the
autotune gives up after 80 iterations.
AlphaMax autotune algorithms only engage at
input power levels of 30 watts or greater, where
the improvement in efficiency will provide a
Autotune operation may be stopped by
clicking on AUTO OFF under Alpha/Remote
or may be stopped by hitting either TUNE or
LOAD UP or DOWN buttons on either the
front panel of the 87A or under AlphaRemote.
The optimum settings of the tune and load
controls is dependent on both drive level and
antenna impedance. SSB is an amplitudevarying modulation and the firmware will make
adjustments during operation but may take a few
seconds to finalize the best settings for the
particular amount of drive. CW autotune
typically happens somewhat faster.
AlphaMax may be engaged remotely from the
AlphaRemote software by clicking on AUTO with
the left button of the mouse. AlphaMax may
also be engaged locally by pressing the ENTER
button simultaneously with the LOAD^ button.
When AlphaMax is operating, the DEFAULT
LED will flash.
AlphaMax will attempt to make up to 80
adjustments of the TUNE and LOAD controls in
order to find the optimum settings. Under some
conditions AlphaMax will not be able to find an
optimized setting within the parameters as
defined in the firmware. Under such conditions
AlphaMax will stop hunting and the DEFAULT
LED will stop flashing. AlphaMax may be
restarted by clicking on the AUTO button in
AlphaRemote or depressing ENTER and
LOAD/UP simultaneously. (Note:
transceivers appear to have a power drop after a
few seconds of operation and this power drop
(and subsequent power increase after a few
seconds in receive) will tend to make AlphaMax
hunt for the proper settings for more than 80
tries and then shut off. This is a problem with
the transceiver and the transceiver should be
It is advisable to store different default values for
a given band and band segment as a better
The AlphaMax algorithm will tune up the 87A
into an acceptable range (or window) of
values. Manually tuning may result in slightly
better settings. For best results and fastest
operation manually tune the 87A to the best
setting for the preferred antenna and drive
level and then store these settings as the
DEFAULT values. AlphaMax will then adjust
the tuning and loading controls only when the
antenna impedance changes or the drive level
AlphaMax will attempt to tune the 87A to the
optimum gain point, which results in maximum
efficiency and lowest distortion. Under high
drive levels this may result in more than 1500
watts output. Output power should be
adjusted by setting the input drive level to the
appropriate level rather than by mis-tuning the
amplifier to reduce power output.
Three new commands control autotune
AUTOTUNE - queries and returns the
autotune status
AUTOTUNE ON - enables autotune
AUTOTUNE OFF - disables autotune
When autotune action is disabled, the
LOAD/UP and TUNE/DOWN LEDs provide a
indication of what action would be taken if
autotune was enabled. For example, when
the grid current exceeds the threshold value
Page 24
Alpha 87A User Manual Rev 2.0
associated with the current input power level, the
LOAD/UP LED will be turned on to indicate
which action would be taken by the autotune
algorithm if it was enabled. If the autotune
subroutine determines that the gain is too low,
the TUNE/DOWN LED will flash to indicate that
autotune action would adjust both TUNE and
LOAD values in an attempt to increase the gain.
The above serial port commands may be utilized
by software other than AlphaRemote.
AlphaMaxdoesn’t change normal operation of
your ALPHA 87A in any way. You can activate
or de-activate AlphaMaxat the touch of a
button, but we don’t think you’ll want to turn it
off. And it’s easy to install in any 87A; a
qualified technician can do it in about 15
NOTE: AlphaMax can be used without
AlphaRemote (see below). However,
AlphaRemote REQUIRES the installation of
AlphaMax first. AlphaRemote utilizes new
commands that are only available in the
AlphaMax ROM upgrade.
AlphaRemote is new software to add remote
control to your Alpha 87A. It requires the
connection of a Windows based computer to
your 87A via the serial port.
NOTE: AlphaRemote will work with the
Alpha/Power Digital Antenna Selection (DAS)
antenna selector installed but requires that the
instructions in the DAS manual concerning the
serial cable be followed exactly.
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Alpha 87A User Manual Rev 2.0
There are lethal voltages in the Alpha 87A amplifier. Special
precautions must be taken to allow for the safe completion of these
1) Always unplug the amplifier from the 240 vac mains before
opening the case and doing any work on your 87A.
2) The high voltage crowbar activates when the cover is removed
and should eliminate any residual high voltage within the amplifier
but it is always prudent to short the high voltage to ground in the
area of the tube plates or the plate RF choke with an insulated
screw driver as an extra precaution.
3) Do not attempt to test the modifications with the cover removed
since the built-in interlocks will not allow the amplifier to be
4) Do not defeat the interlocks as a means of testing the amplifier
with the cover removed. Proper operation of the amplifier requires
that the cover be in place for shielding the digital circuitry from the
radiated RF signal.
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Alpha 87A User Manual Rev 2.0
AlphaRemote Operating Procedures
AlphaRemote software allows you to control the Alpha
87A from a computer screen under MS Windows TM with
a mouse. The front panel controls of the 87A are
represented on the monitor screen and can be actuated
with a “left click” of the mouse.The Alpha 87A must be
plugged into the AC Mains before the AlphaRemote
software is started. But the 87A does not have to be
turned ON. The 87A microprocessor runs whenever the
87A is plugged into the AC mains and the AlphaRemote
software initializes the amplifier each time it is started. If
the amplifier is not properly initialized, the bar graph
metering in the AlphaRemote software will not operate. If
this situation occurs then the 87A was not AC powered at
turn on and the software will need to be restarted once
the 87A is plugged into the AC Mains.
The display format of the AlphaRemote software may be
controlled by holding down the “left button” of the mouse
while the cursor is on the lower left or lower right corner of
the current display. By “dragging” the display to an
alternate shape the display will change to the format
desired–as shown in Figure 2. showing the display
Power ON and OFF, Mode OPERATE and STANDBY,
and High Voltage HIGH and LOW can be controlled by
left clicking on their appropriate “button”. The current
status of the 87A is displayed on the STBY, OK, and
READY indicators.
TUNE and LOAD settings can be changed manually by
clicking on the “up” and “down” arrows.
Manually changing the TUNE and LOAD controls using
either the controls on the 87A or the equivalent controls
on the Windows screen will result in AlphaMax being
turned of. To engage the AlphaMax software again you
can either clicking on the AUTO button again or by
simultaneously pressing the 87A’s ENTER and LOAD^.
The software DEFAULT and ENTER buttons operate in
the same fashion as the controls of the same name on
the front panel of the 87A.
Status and fault messages are displayed in the window
under the control buttons.
The bar graph meter displays differ from the LED
displays in that the entire display changes color when a
limit is exceeded. This aids in determining when the
amplifier is being driven beyond its normal conditions.
Experimentation with the mouse will quickly provide
additional information on the operation of the 87A via the
AlphaRemote software. Every effort has been made to
ensure the operation of the software is intuitive and
closely simulates normal operation of the front panel
Band and Segment selection is made with pull down
menus by left clicking the mouse and selecting the
desired band and segment.
AUTO TUNE (AlphaMax firmware) can be engaged by
clicking on the AUTO button. If the autotune disengages
the text display will notify the operator and the AlphaMax
firmware can be restarted by clicking on the AUTO button
again or by simultaneously pressing the 87A’s ENTER
and LOAD^.
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Alpha 87A User Manual Rev 2.0
Installing the AlphaRemote Software
1. Close any programs running under Windows.
2. Insert AlphaRemote CD into CD drive (or disk #1 in
floppy drive).
3. Click START on taskbar, then RUN.
4. Click BROWSE and select My Computer,
X:\setup.exe, then click OPEN. When X:\setup.exe
is showing in RUN window, click OK to start
installation of AlphaRemote. Follow the instructions
on screen. (Note: X is the drive letter for your CD or
floppy drive).
5. To run the AlphaRemote program click START on
taskbar, then PROGRAMS, then select the Program
Group where software was installed (default is
AlphaRemote). Click the AlphaRemote icon once to
start program. (NOTE: The Alpha 87A must be
connected to the AC power BEFORE starting the
8. The front panel controls of the amplifier are
duplicated in the AlphaRemote window. Both Local
and Remote control of the 87A are possible when
the program is running.
9. A standard 25-pin to 9-pin modem cable will provide
the correct connections between the Alpha 87A and
computer serial port for 4800 baud data. If a 25-pin
to 25-pin cable is used between the 87A and
computer, refer to attached sheet (or page 19 of the
87A Operating Manual) for pins that must be
disconnected at one end of the cable.
10. If AlphaRemote software is to be used with an 87A
which also has a DAS connected, the cable between
the DAS and computer must have pins
disconnected on the DAS end (see attached sheet).
This is necessary whether using a 25-pin to 9-pin
cable OR a 25-pin to 25-pin cable between the DAS
and computer.
6. Click once on CONTROL, then CONFIGURE, then
ADD AMPLIFIER. Select the desired serial port.
The default SETTINGS for communications
parameters will be correct if a standard 25-pin (87A)
to 9-pin (computer) modem cable is used (see
paragraph 9 below). Click OK to save the selected
7. If you have more than one 87A then select another
amplifier to configure or click OK to close the
CONFIGURE window if you are only setting up one
87A. The AlphaRemote window will open showing
status and operating parameters of the selected 87A
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Alpha 87A User Manual Rev 2.0
Figure 8.
Examples of
Select the desired configuration by clicking and
holding down the left mouse button while the
pointer is touching either the lower left or lower
right corner of the current display and dragging
the display into the desired format.
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Alpha 87A User Manual Rev 2.0
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Alpha 87A User Manual Rev 2.0
How to Operate the 87A
Regardless of what frequency the ALPHA 87A was previously on, it is necessary only to apply AC
power, wait 3 minutes for tube warm-up, and apply a few watts RF drive*. If driven on a band different
from its existing setting the 87A automatically bypasses the transceiver output to the antenna for about
one second while it change bands and tunes up. It then switches itself back in-line and the operator
can confirm approximately 13-15 dB (20x-30x) power gain.
FCC rules do not permit new amateur amplifiers to be operable on 24-30 MHz as delivered
within the US and possessions. Owners who send Alpha Customer Support a photocopy of
their authorizing amateur license will promptly be provided information on “unlocking” 12 and
10 meter coverage.
Step-by-step Procedure
b) After the red WAIT (tube warm-up) LED
extinguishes, the OPR LED will light.
Apply 10-25 watts of excitation on the
desired operating frequency.
mode) so that peak output as indicated
on the RF OUTPUT bargraph is about
1.5 kW. (Once you’ve become familiar
with operation of your ALPHA 87A, it’s
quite possible that you won’t need to readjust transceiver output when changing
c) Automatic band change and tune-up,
when necessary, require only about one
second, during which time transceiver
output is by-passed directly to the
antenna. After the Alpha switches back
in line, adjust drive power (in the desired
With RF output peaking near 1.5 kW, highest
indicated grid current peaks should be 20-50
mA to insure both efficiency and linearity. If
peak grid current is higher or lower, drive from
the transceiver can be adjusted to correct it.
Alternatively, the ALPHA 87A’s field (user)
a) Press POWER ON button; set mode
switches to HI and OPR.
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Alpha 87A User Manual Rev 2.0
programming capability may be used to
accurately match the actual antenna in use
while achieving optimum efficiency and
linearity at the power level desired. See
Section 7.2.
7.1 ALC: Alpha Radio Products does not
recommend use of ALC (Automatic Level
Control) in most cases. In the rare case
where faults or distortion recur because
exciter power output cannot be adequately
controlled, ALC feedback may be useful. See
Sections 10.1 & 10.2.
7.2 User Tuneup Programming: The
ALPHA 87A may easily be field-programmed
as follows to achieve maximum efficiency and
desired loading into the user’s actual
antennas on any frequency within the
capability of the amplifier:
Each of the 5 channel memories represented
by the 5 SEGMENT buttons may be userprogrammed for any frequency within the
tuning range of each band. The frequency
labeling of SEGMENT buttons applies only to
factory programming and to user segments
programmed at the same center frequencies
(e.g., 1.860, 14.050, or 28.600 MHz).
Therefore it’s usually convenient (but not
required) to use factory center frequencies
when user-programming amateur bands.
Each segment is identified in memory by its
center frequency and nominal width. During
automatic segment selection the amplifier
seeks first the nearest user segment centered
within + 50 kHz of the drive frequency (10m,
+200kHz, 160m, +20 kHz), then such a
factory segment. If neither exists it selects the
nearest segment.
The basic approach to user programming is to
use the TUNE meter function to pre-adjust
tuning and loading at the desired frequency
(for amateur use, preferably the center of a
factory segment) with the actual load. Then
“fine tune” to peak output power, and finally
save the resulting tuning data in amplifier
7.3 Pre-Tuning Using the TUNE Meter: The
goal (for 1.5 kW peak output) is to adjust
LOAD and TUNE alternately until the TUNE
LED is positioned at the mid-scale “V” mark.
Heavier loading results when the LED is to the
right of mid-scale, while lighter loading occurs
when the LED is to the left.
Pre-Tuning Procedure
a) Select the TUNE meter function and
apply about 20 watts drive at the
center frequency of the segment to
be programmed.
b) Use the TUNE buttons to move or
“dip” the TUNE bargraph as far to
the left as possible.
c) If the TUNE indicator is to the left of
the desired position, press the
(up) button until the
indicator moves to the desired
position, OR
d) If the indicator is to the right of the
desired position, use the LOAD
(down) button instead.
e) Repeat steps 2. and 3. above until
the TUNE indicator is correctly
positioned for the power level
7.4 Final Touchup & Data Storage:
a) Increase drive until the RF output is
about 1kW. TUNE for maximum RF
b) If the grid current reaches 70mA
during operation at or below the
desired power, press the LOAD
button once to increase loading and
then retune for maximum RF output.
Repeat if necessary until peak grid
current at desired output is 2050mA.
Page 32
Alpha 87A User Manual Rev 2.0
IMPORTANT: As the final tuneup
step, always adjust TUNE for
maximum RF output.
c) To store tuning data in memory,
press ENTER. While the ENTER
LED is flashing, press the desired
SEGMENT button.
d) Continue as above with remaining
bands and segments.
1. User segments may be reprogrammed
any number of times by simply repeating
the procedures for Pretuning and Final
2. If bad user data is entered for any
segment, factory data may be substituted
by selecting the segment, pressing
DEFAULT, ENTER, and then the
segment button again.
3. Arrows (up or down) under TUNE
buttons indicate increase or decrease
tuning capacitance, respectively.
4. Arrows under LOAD buttons indicate (up)
greater or (down) lighter loading.
Increased loading moves the TUNE LED
to the right, decreased loading to the left.
5. A lighted TUNE or LOAD button LED
indicates the capacitor has reached its
rotational limit. Capacitor rotation is 100
steps limit-to-limit.
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Alpha 87A User Manual Rev 2.0
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Alpha 87A User Manual Rev 2.0
Protective Functions and
The ALPHA 87A's microprocessor-based control system constantly monitors various signals and
conditions within the amplifier. If any signal or condition is detected that could cause damage or
improper operation, the amplifier enters a fault condition. There are two types of faults; soft faults and
hard faults. Both cause the amplifier to stop operating, hard faults cause the amplifier to turn itself off.
Soft Faults
Soft Faults may be caused by two conditions:
1. Improper operating conditions, usually overdrive (and possibly excessive plate or grid current),
high load VSWR, or improper T/R control cable connections or timing.
2. Abnormal amplifier conditions (e.g. low bias) which may result in damage in the OPERATE mode.
When such a condition occurs, the control system automatically switches the amplifier to STANDBY.
The FAULT LED lights, and one or more of the five SEGMENT LEDs display a binary fault code
(faults numbered 33-37 and 99 are displayed differently, as described in the following Fault Codes
Section.) The code displayed indicates the nature of the fault as follows:
Segment buttons----------------->
LEDsDecimal value of LED if flashing:
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Alpha 87A User Manual Rev 2.0
The fault number is determined by adding the values of all lighted LEDs.
Example: (+ = flashing LED, o = dark) + o o + + = fault code number (16 + 2 + 1) = 19. A listing of
fault codes with a brief explanation of each can be found in the following Fault Codes section.
To reset a soft fault:
Return the transceiver to receive
Switch the ALPHA 87A to STANDBY
Correct the condition that caused the fault, and finally
Return the ALPHA 87A to OPERATE
Hard Faults
Failures such as HV shorts (extremely high plate current) or bias or control system failure result in
immediate shutdown of amplifier AC power to avoid damage.
To reset a hard fault:
After the cause of the hard (power-off) fault is corrected, simply press the ON button. The fault code
will then be displayed on the SEGMENT LEDs for 30 seconds during warm-up, and then clear
automatically. You must not turn off the power before the
fault clears, or it will log another hard fault the next time the power is turned on.
Six of the SAME hard fault shutdowns over ANY period of time (with no other kind of Hard fault) will
then put the 87A in Fault 99 which locks it up. This function was put in the amplifier to prevent any
further damage if operation was attempted after a failure had occurred.
If the hard fault persists refer to Chart 2 in Troubleshooting Section.
ALC: In the rare case where faults or distortion recur because exciter output can’t be well controlled,
refer to Section 10, Troubleshooting Suggestions.
Page 36
Alpha 87A User Manual Rev 2.0
Fault Codes
Note: You must not turn off the power before the fault clears, or it will
log another hard fault the next time the power is turned on.
*(+=flashing LED, o =
C dark)
Receive PIN back bias voltage not at minimum
required level with key down and no RF drive.
Same but with R/F drive present.
ooo +o
Five volt supply voltage too low.
Five volt supply voltage too high.
Plate voltage abnormally low.
Plate voltage abnormally high.
Cathode and/or power PIN diode back bias (109V) not switching to the required low level with
key down.
Transmit PIN diode back bias below minimum
required value key up.
Transmit PIN diode forward current below
minimum required value key down.
Transmit PIN diode forward current exceeds
maximum limit key down.
Excessive input reflected power.
Excessive and unsafe drive power.
Excessive load reflected power or RF voltage.
May be caused by excessive load VSWR at an
otherwise acceptable power (e.g. 4:1 at 1.5 kW)
or excessive power at otherwise acceptable load
VSWR (e.g. 2.5 kW at 1.9:1).
Page 37
Alpha 87A User Manual Rev 2.0
Plate current greater than 1.35 amp for more than
4 seconds continuous. Note: The Ip button LED
flashes for several seconds before a fault 16 Ip
trip occurs.
Abnormally low or high amplifier power gain.
Usually due to extreme mis-tuning or possibly an
RF arc.
Filament current less than 2.0 amp. Possible
open tube filament.
Filament current greater than 3.5 amp. Possible
shorted filament.
Excessive tube temp. in transmit (key down);
abnormal dissipation and/or insufficient airflow.
Control system fault; D/A feedback)” not working.
Control system fault; D/A feedback “1” not
System voltage fault. High voltage, +/-15 volts, or
–109 volts below safe operating level.
RF drive before or without amplifier keyed
(possibly mis-sequenced T/R), or attempted
automatic band change with excessive RF drive.
Attempt to transmit on invalid frequency, such as
above 24 MHz without unlocking 24-30 MHz
Excessive grid current; above 100mA
continuously for 2 seconds. NOTE: Red LED in
Ig bargraph flashes before Ig trip occurs.
& LEDs
Control system fault; TUNE capacitor not
& LEDs
Control system fault; TUNE capacitor not moving
or zero sensor position not working.
& LEDs
Control system fault; LOAD capacitor not
& LEDs
Control system fault; LOAD capacitor not moving
or zero sensor not working.
Page 38
Alpha 87A User Manual Rev 2.0
LEDs Hard
Unit refuses to turn on
Control system fault; bandswitch not moving.
Results when the same hard fault occurs 6 consecutive times
without one successful power-up.
Call Alpha Customer Support at Alpha Radio Products
for advice if this occurs. This fault protects the amplifier
against repetitive abuse and cannot be cleared with user
controls. Warranty will not apply to resulting damage if
this fault is reset by user without factory authorization.
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Alpha 87A User Manual Rev 2.0
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Alpha 87A User Manual Rev 2.0
RS-232 Serial Communications
The status of the amplifier can be determined
via an RS 232 serial communications link.
You need to use a modem communications
For example, Windows
95/98/NT/2000 comes with one called
HyperTerminal. It is usually located under
configuration files can be downloaded from, in the tech tips
When you click on HYPERTRM.EXE, it will
open a window for a new connection. Give it
a name, and in the next window select the
"Connect Using: Direct to COMx" pulldown
menu (in the bottom of the box on my version
of Win95); select the Com port you will use.
This is the same one that you were using with
the AlphaRemote software. If the COM port
you select is available it will open another box
called "COMx Properties". Going down the
list, select Bps-4800, Data bits-8, ParityNONE, Stop bits-1, Flow control-NONE. Click
OK to close the window. Now pull down the
FILE menu and click PROPERTIES. Click the
SETTING tab and then click ASCII SETUP at
the bottom of the window.
Click the box for "Echo typed characters
locally" (it could have a check in the box).
Click OK to close both windows.
respond with the firmware version number. If
you see garbage you will need to remove pin
22 of the 25-pin end of the cable (the 87A
end). It is used to set the baud rate of the
amplifier (see below for a complete
explanation of connections).
Once communications are established with
the amplifier, type SF and HF to display the
Fault and Hard Fault logs (press Enter key
after each command). Save the result of
those commands. A list of more commands
follows this section.
Plug in the amp (power off) and it should be
communicating with the computer. Type VER
and press the Enter key. The 87A should
Page 41
Alpha 87A User Manual Rev 2.0
Communications Link Set-up
Line set-up (default):
Baud rate:
Data bits:8
Stop bits: 1
Terminal set-up:
Terminal emulation:
TTY, ANSI, VT102, etc.1
1 The ALPHA 87A needs no emulation as it provides only ASCII output with no control codes.
Serial control lines
Computer or
To >>
DB-25 M
DB-9 M
Pin 2
Pin 2
Pin 3
Pin 3
Pin 3
Pin 2
Pin 4
Pin 4
Pin 7
Pin 5
Pin 5
Pin 8
Pin 7
Pin 7
Pin 5
Make no connection from pins 9, 22, 12, 13, or 14 of the DB-25 F connector on the ALPHA 87A to the
computer or terminal. These pins are used for baud rate and diagnostic modes of the unit.
Optional baud rate select:
Baud rate
Pin 12
Pin 22
Pin 9
Baud rate
Pin 12
Pin 22
Pin 9
Page 42
Alpha 87A User Manual Rev 2.0
Default 4800
Example: To set baud rate to 9600, tie pins 12,22 and 9 to pin 7 (signal ground).
View of Male Connector (pin end).
Page 43
Alpha 87A User Manual Rev 2.0
Remote Commands
OFF or ON mode commands:
Is AC power on or off?
Turns AC power off.
Turns AC power on.
Turns AC power off. Same as AC OFF.
Reports date code and serial number
Displays a list of available commands.
Reports (up to) eight most recent uncorrected hard faults.
What is RS-232 hand-shaking flow control set to?
Sets hand-shaking flow control off.
Sets hand-shaking to hardware flow control.
Are front panel controls enabled or disabled?
Disables the front panel controls.
Enables the front panel control.
Reports date code and serial number.
Reports (up to ) eight most recent soft faults.
Reports unit status: state warm-up, standby, or operate: HV mode,
low or high; 24-30 MHz enabled or disabled, panel enabled or
disabled, frequency last entered, band last selected, segment last
used, tune and load capacitor positions.
Reports version of firmware installed.
ON mode commands:
Reports current band setting: band 1 for 1.8 MHz through band 9 for
28 MHz.
BAND # (1-9)
Sets band switch to any band one through nine.
Sets band switch down one band.
Sets band switch up one band.
Sets tune, load and frequency to default or factory settings.
Used to diagnose unit with factory assistance.
Use with SEG command for saving data.
What frequency is the unit on or last frequency used?
FREQ # (in kHz)
Sets up unit for this entered frequency.
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Alpha 87A User Manual Rev 2.0
Reports current grid current in mA.
ON mode commands:
Reports current load capacitor setting (0-100).
LOAD # (0-100)
Adjusts load capacitor setting (0-100).
Adjusts load capacitor down one step.
Adjusts load capacitor up one step.
Reports 24-30 MHz disabled or enabled.
LOCK # (24-30 MHz With unit in proper configuration, the unit can unlock 24-30 MHz
unlock code)
bands with this command.
Reports current reading of the front panel multimeter.
Sets multimeter to HV mode & reports value.
Sets multimeter to Ip mode & reports value.
Sets multimeter to TUNE mode & reports value.
Reports current HV power supply setting, HI or LO.
Sets high voltage power supply to high mode.
Sets high voltage power supply to low mode.
Reports whether in operate or standby.
Sets to standby mode.
Sets to operate mode if ready.
Reports current forward power out in watts.
Reports current load reflected power in watts.
Reports current segment setting.
SEG # (1-5)
Sets segment to entered value.
Sets segment down one from previous.
Sets segment up one from previous.
Reports current tune capacitor setting (0-100).
TUNE # (0-100)
Sets tune capacitor to value entered.
Sets tune capacitor down one step.
Sets tune capacitor up one step.
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Alpha 87A User Manual Rev 2.0
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Alpha 87A User Manual Rev 2.0
Owner Assistance
Assistance is available from Alpha Radio Products Customer Support at 303.473.9232, by fax at
303.473.9660, or by email at [email protected]
Most apparent problems with the ALPHA 87A, especially when first putting one into operation, result
directly from failure to observe carefully the procedures given in this manual, especially those repeated
as cautions on pages 1 and 2 of the manual and on the handy quick-reference card provided. A few
other points learned from experience are given here.
Overdrive related faults
(13 & 26)
These nearly always result from failure to set
up transceiver power controls properly. Most
transceivers have two power-related controls,
which operate in an independent fashion.
Setting the transceiver POWER or RF PWR
control IS NOT SUFFICIENT. Several
popular transceivers can generate RF spikes
of 200-300W or more and output may vary
widely from band-to-band and mode-to-mode
unless the transceiver internal ALC (drive
level) also is adjusted carefully according to its
manufacturers’ instructions! Typically, this is
done with a knob labeled DRIVE (IC-781, FT1000), PROCESSOR OUT (TS-940, TS-950)
or, on SSB when speech processing is not in
use, MIC or MIKE.
Automatic Level Control is a system used in
transmitters, which is similar in operation to
AGC (Automatic Gain Control) in receivers.
When the signal at some reference point in an
amplifier chain exceeds a preset level, a bias
voltage is generated and used to reduce the
gain of a preceding, low-level driver stage.
The effect is to more or less limit drive and
output to the preset level.
Alpha Radio Products, LLC. does not
generally recommend use of ALC from
amplifier to transceiver because smooth,
distortion-free operation requires that
characteristics of the ALC bias source be
matched to those of the controlled stage.
characteristics are not standardized; each
model has its own unique gain and dynamic
characteristics. (Internal ALC in transceivers
works well because the ALC source and
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Alpha 87A User Manual Rev 2.0
current of 50 mA.
With some
transceivers (e.g. recent ICOMs) this pot
setting may be only a fraction of a turn
clockwise from the counterclockwise
stop; with Kenwoods and some other
transceivers it may be half to nearly full
clockwise rotation.
controlled stage are designed together, as a
ALC feedback from ALPHA 87A to
transceiver normally isn’t necessary because
the power output of most modern transceivers
can be quite accurately controlled as
discussed above, and because the ALPHA
87A’s grid current limiting system easily
absorbs occasional drive peaks. Extensive
tests with TS-850, TS-940, TS-950, IC-761,
IC-781, IC-756, IC-746, FT-1000, and FT1000MP transceivers have revealed no need
for ALPHA 87A-to-transceiver ALC feedback
to achieve excellent results.
However, the 87A does incorporate an
excellent and versatile ALC generator.
Therefore, in the rare case where transceiver
output cannot be adequately controlled, this
can usually be handled by using ALC
feedback if the transceiver has an input for
negative-going-from-zero ALC. (This type of
ALC is standard with most modern
In this case, (refer to Figure 7, p. 18) connect
the transceiver ALC input to the ALPHA 87A’s
phone-type ALC jack with a shielded cable.
Turn the ALC adjust pot fully clockwise to start
(except set it to mid-rotation when using Icom
The adjustment goal is to use the smallest
amount of ALC feedback (the least clockwise
rotation of the ALC pot) that will eliminate
overdrive faults and distortion. No fixed
universal procedure exists, but the following
should give good results:
With the ALPHA 87A in STBY, set
transceiver peak RF output in CW or
SSB as close as possible to the power
level (approximately 50W) needed to
drive the amplifier to 1.5 kW.
Check under both CW carrier and SSB
voice conditions for any sign of instability
or “motorboating”. If either is detected,
try turning the ALC pot in small steps
while monitoring results.
experimentation will probably be
necessary to find the best adjustment; a
monitoring scope such as the Kenwood
SM-220 may be useful in evaluating
Repeated power-off shutdowns (typically fault 1, 5,
8, or 16)
During the first hundred or so hours of
operation, even when in receive or standby a
new amplifier may simply shut off. The
shutdown may be accompanied by a modest
“thump.” Usually this is the result of internal
tube flashovers, or “hiccups,” which are
characteristic of many new ceramic-metal
tubes. “Thumps” generally occur infrequently
and stop entirely after one to perhaps ten
occurrences without causing damage or
indicating a tube defect.
When such a shutdown occurs, reapply AC
power. For possible future reference make a
note of the fault code number which is
displayed on the SEGMENT LEDs for the first
30 seconds thereafter.
b. Switch the amplifier to OPERATE and,
while driving it as above, turn the ALC
pot counterclockwise (CCW) as far as
possible without exceeding amplifier grid
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Alpha 87A User Manual Rev 2.0
No response (or immediate shutdown)
when the POWER ON button is pressed,
or the occurrence of such shutdowns
more than about ten times, may indicate a
more serious problem. In such a case,
Alpha Customer Support should be
contacted before proceeding.
1. Footswitch use: Users have found that
some footswitches exhibit contact bounce,
which can intermittently cause improper T/R
sequencing. Usually this shows up as
amplifier drop-out (exciter bypass to the
antenna) on occasional CW characters or
SSB transmit periods. A capacitor of about
.01-.10µf across the switch contacts normally
cures the problem. Use the smallest value
that works.
2. Repeated high or low voltage hard faults
(e.g. faults 1-6): Is the primary voltage tap
correctly set (See section 4.3)? Is an AC line
unusually high or low, or regulation bad?
Check wiring.
3. Overtemperature fault 21: Are air intake
(rear panel) and exhaust (above tubes)
openings clear of obstructions? A log book
lying on top of the amplifier? Intake and
exhaust openings should be at least 6 inches
clear of any obstructions, and amplifier must
be located so that hot exhaust air cannot
recirculate into the air intake.
4. Fault 22: This is a typical result of incorrect
transformer installation, (e.g., a connector not
properly mated and seated.)
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Alpha 87A User Manual Rev 2.0
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Alpha 87A User Manual Rev 2.0
ALPHA 87A Functional
The complexity of the ALPHA 87A is such that describing its circuitry in detail here is impractical.
However, its basic functional organization is quite easily understood from the following:
Figure 8 (page 37) is a simplified block diagram of the ALPHA 87A, and Figure 9 (page 38) is a
simplified schematic showing the principal RF signal paths and primary AC power circuits.
Principal Functional Components
The following block diagram emphasizes the
principal functional components as follows:
Heavy rectangular boxes represent individual
modules of the amplifier, in most (but not all)
cases circuit boards (PCBs).
a. Signal paths used in both transmit and
receive are shown by heavy solid lines.
e. designations of the control, monitoring
and power distribution lines, which
comprise it.
Principal interfaces to the outside
(connectors & controls) are located
around the perimeter of the block
b. Signal paths used only in transmit, by
heavy dashed lines.
Signal paths used only in receive, by
heavy dotted lines.
d. Internal wiring harnesses are shown as
light solid lines. Each is labeled with the
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Alpha 87A User Manual Rev 2.0
Schematic Description
Transmit signal path: Drive from the transceiver, applied at the TX RF INPUT connector, passes
sequentially through the input wattmeter, tube deck T/R section, input T/R PCB, input matching
network, (pair of) 3CX800A7 triode tubes, plate tuning network, output pin diode PCB, output T/R
PCB, and output wattmeter PCB to the tx rf out/rx rf in jack.
Receive signal path: TX RF out/RX RF in jack, output wattmeter, output T/R PCB, input T/R PCB,
input T/R PCB, tube deck T/R section, and input wattmeter to the TX RF input jack (which is, of
course, also the RX signal output to the transceiver).
RS-232 communications port: This 25 pin connector and wiring to it is located at the lower left
corner of the block diagram.
Schematics Available
One set of current Alpha 87A schematics will be provided at no charge to any owner on request, and
assistance with specific questions or problems is always available from Alpha Power Customer
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Alpha 87A User Manual Rev 2.0
List of Figures
Page Number
Transformer installation
Inside top view
View with front panel lowered
Front panel view
Rear panel view
Examples of AlphaRemote screen configurations
ALPHA 87A Functional block
ALPHA 87A Simplified schematic
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Alpha 87A User Manual Rev 2.0
Alpha Radio Products (Alpha Radio Products LLC) WARRANTS
Workmanship and all components except RF power tubes are warranted for FOUR YEARS from
date of original purchase if used exclusively in licensed amateur radio service. WARRANTY IS
VOIDED BY ILLEGAL SALE OR USE OF EQUIPMENT (e.g. U.S. sale of export models).
All power tubes are warranted for one year. Eimac power tubes are warranted by their
manufacturer; warranty requests on Eimac power tubes must be submitted to Alpha Radio
Products. Svetlana power tubes are warranted by Alpha Radio Products for one year from date of
original purchase. Installation and use of power tubes not authorized by Alpha Radio Products will
render any and all remaining warranty null and void.
Warranty does not apply to repair of damage resulting from neglect, abuse, power surges
(generated by lightning strikes or defective public service) or improper installation, nor to units not
operated in accordance with specifications and instructions furnished by Alpha Radio Products.
The Warranty will be considered null and void if the unit is repaired or altered with parts and/or by
persons not authorized by Alpha Radio Products, or in cases where the serial number has been
removed, altered, or defaced.
If a malfunction is suspected, before attempting repairs or returning equipment to Alpha Radio
Products for service, the owner shall contact the Alpha Radio factory service department,
providing model and serial number plus details of equipment hookup, accessory equipment used,
operating conditions, and abnormalities observed. Alpha Radio Products will furnish a new part in
exchange for any covered defective part or, if it is determined that factory service is required, will
authorize return to factory. Equipment authorized for return shall be shipped to Alpha Radio
Products fully prepaid and insured, USING ONLY FACTORY APPROVED PACKING; REMOVE
FROM THE FACTORY WITH TRANSFORMER REMOVED! Shipping charges, to and from the
factory, and a $25.00 service fee are the responsibility of the owner.
Original purchasers will be informed of any required factory maintenance. Alpha Radio Products
will make a best-faith effort to publicize required factory maintenance via Internet and press
releases for owners who did not purchase affected units from Alpha Radio Products. Units
effected by a required factory maintenance must be returned to the factory for service within OneYear of issuance of required factory maintenance notice. Service, modification and upgrade
charges for units effected by required factory maintenance will be assumed by the owner if said
unit is not returned the factory within One-Year of a required factory maintenance notice. In the
event of required factory maintenance shipping charges to the factory are the responsibility of the
In the absence of an Alpha Radio Products sales receipt the term of the four-year warranty will be
assessed by the unit’s construction date.
No person is authorized to assume for Alpha Radio Products any liability in connection with our
products, other than as set forth in this warrant. Alpha Radio Products reserves the right to
change its products as it deems desirable, without obligating itself to make such changes
available for previously manufactured products.
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Alpha 87A User Manual Rev 2.0
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