MODEL 99 Operating Manual Alpha 99 Power Amplifier
i Manual Alpha 99 Rev 1.
ALPHA 99 Operating Manual ALPHA POWER PRODUCTS 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. © Radio Alpha Products Inc. 6185 Arapahoe Road • Boulder, CO 80303 Phone 303.473.9232 • Fax 303.473.
DISCLAIMER Information in this document is subject to change without notice. Information provided by Radio Alpha Products Inc.® is believed to be correct and reliable. However, no responsibility is assumed by Radio Alpha Products Inc., unless otherwise expressly taken. Companies, names, and data used as examples are fictitious, unless otherwise noted.
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Table of Contents Introduction 7 General Description of the ALPHA 99 Amplifier 7 Equipment Shipped 7 Safety: Installation and Operation 7 Specifications, ALPHA 99 9 Before Installing Your Alpha 99 11 AC power Source 12 Antenna 12 Coax and Connectors 13 Air Flow 13 RF Safety 13 Before Operating Your Alpha 99 14 Figure 1 - Top View 15 Carefully unpack amplifier and transformer. 17 AC Primary Connections & Amplifier Grounding. 17 Install the transformer.
Fuses 31 Plate Overcurrent Relay 31 Idling Plate Current And Electronic Bias Control (Ebs) 31 RF & Mistuning Protection 31 Preventive Maintenance 33 Figure 6 – Simplified Chassis Schematic 38 Figure 7- Display Board ABX-X400 39 Figure 8 – Control Board ABX-X401 40 Figure 9 – Control Board ABX-X401 41 Figure 10 – T/R Status Board, Multimeter Switch and Switch Matrix Board 42 Figure 11 – Power Supply Board 43 Figure 12 – HV Filter and Screen Supply Board 44 Figure 13 – T/R Status Board
1 Section IMPORTANT! Critical precaution during installation of your Alpha 99: While the cover is removed to install the power transformer, make sure that the tubes are properly installed as described in Section 2. Failure to do this may cause severe damage or destruction of both tubes. Such damage is not covered under warranty.
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. Warnings: What Not to Do 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. Never attempt to turn on the amplifier without the cover in place.
Specifications, ALPHA 99 Frequency Coverage: All amateur bands 1.8-29.7 MHz* plus most non-amateur frequencies 6.0-19.0 MHz and 20.0-30.0 MHz. Power Output: 1500 watts peak all modes, including SSB, CW and continuous or modulated carrier. Carrier operation (e.g., A0, RTTY or FM) for more than 5 minutes at or near maximum rated power requires use of the auxiliary cooling fan accessory.) Drive Power: 50 to 60 watts nominal for rated output. Power Gain: Nominally 14 dB, a power increase of 25 times.
Protective Functions: Grid and screen current limiting; trip to standby (automatic reset) for excessive VSWR or average plate current, RF arc, severe mistuning; AC off trip for HV fault; primary and step-start fuses; cover AC interlock and HV crowbar switches; AC inrush-current limiting (Step-start). Status Indicators: STANDBY, WAIT (initial turn-on time delay), OPERATE and FAULT LEDs.
WARNING –READ THE MANUAL CAREFULLY BEFORE INSTALLING YOUR ALPHA 99. The ALPHA 99 is extremely easy to install, 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 Installing Your Alpha 99 1. Be careful not to twist or warp the chassis when handling the amplifier with its cover removed.
Station Engineering Considerations The 99 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.
Coax and Connectors The importance of a well constructed feedline 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, installations are encountered where cheap/poor/under-rated/old coax and connectors are probably responsible for at least one S unit of degradation.
WARNING –READ THE MANUAL CAREFULLY BEFORE OPERATING YOUR ALPHA 99. The ALPHA 99 is extremely easy to 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 99 1. You must set transceiver power output properly. Virtually all damage to date has resulted directly from severe overdrive.
good lightning arrestor, and it’s good practice to disconnect and ground antenna feedlines, and to disconnect AC power, when the equipment is not in use. 6. Never use an automatic antenna tuner into or through the 99. This will cause damage to the Input Wattmeter & Input Relay. Note that many popular transceivers have built in antenna tuners which should be disengaged when driving your amplifier. HAPPY AND SAFE OPERATING.
2 Section Overview of Amplifier Capabilities It is extremely important to thoroughly review the Installation and Operation sections of this manual before attempting to use the ALPHA 99. Failure to do so could result in serious damage not covered under warranty. Continuous RF Output. The 99 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. Compatibility with popular amateur transceiver and exciters.
3 Section Unpack and Prepare for Operation (Refer to Figures. 1-5, pages 13, 19, 21) Carefully unpack amplifier and transformer. Inspect both for physical damage. Save all packing material for future use. AC Primary Connections & Amplifier Grounding. Remove the amplifier top cover. Primary voltage taps are selected at the terminal strip numbered “1” to “7” and located on the mains board mounted on the chassis center divider, left of the transformer.
an absolutely essential part of the cooling system. Make sure the chimneys are straight and fully installed so that the bottom of the chimney is firmly against the tube deck and completely covers the airflow openings in the deck. Tube cooling air must exit only through the tube anode fins; it must not be allowed to escape outside them. Failure to ensure proper cooling airflow may result in tube damage or destruction which is not covered under warranty.
NOTE: Do not operate amplifier without the cover in place and all cover screws installed. Do not operate amplifier without a good RF ground connection on the rear panel ground terminal. Power Cord Connections WARNING! To avoid the hazard of a potentially fatal electric shock and/or severe damage to the ALPHA 99 and other equipment, always use an AC plug that is appropriate for the primary mains voltage, current rating and configuration. NEVER use 120V-type plugs and power receptacles for 190-250V circuits.
If the same circuit also supplies a transceiver drawing peak line current of 5A and a lamp drawing 1A, only 20-5-1 = 14A is available for the amplifier and maximum possible output is about: Po max = (115V x 14A) /2.3 = 1610/2.3 = 700W. RF Grounding A ground stud with wing nut is provided on the rear of the chassis. Connection should be made from this stud to a good RF earth ground, such as a copper water pipe or driven rod, via heavy copper braid or strap.
Figures 2 - 4 - Transformer Installation Radio Alpha Products Inc.
4 Section Amplifier/Station Interconnections See figure 5 Coaxial Cable Types & Connectors Connect the transceiver RF output to the ALPHA 99 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 99 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.
99 ALC potentiometer may be set accordingly. While driving the amplifier, adjust the ALC pot to limit maximum transceiver output as desired. We recommend contacting Radio Alpha Products customer service before attempting to use external ALC with the Alpha 99. Figure 5 - Alpha 99 Rear panel RF OUTPUT to Key In Line from antenna radio ALC ADJUST pot. Key Out Line (optional) to radio. RF INPUT from radio 5060 watts. ALC OUTPUT to radio (not recommended with modern radios) Radio Alpha Products Inc.
5 Section Initial Set-up and Tuning Control Functions (See front cover photo) BAND Use to select amateur band desired (in MHz). TUNE Sets output tank circuit to resonance. Higher frequencies tend to tune toward the “0” end of the dial scale, while lower frequencies tend to tune further toward the “100” end. LOAD Sets amplifier plate loading and determines the power level at which best efficiency and linearity are achieved. In general, loading is heavier at greater scale settings.
POWER: overdrive and flattopping. A switch-selected monitors three additional functions: bargraph TUNE: Permits a simple and safe tune-up procedure to be performed at low output power. See section Tune-up below. IP: Plate current, 1.5 amperes full scale (approximately 75 mA per segment). HV: Plate voltage, 3000 VDC full scale (150 V per segment).
other amplifiers. ALC The 99 grid current limiting circuits provide substantial tube protection against possible damage. The ALC voltage generated by the 99 is for external feedback to transcievers. It cannot control the amplifier itself and is not applied internally. If ALC control is required, a connection must be made from the 99 to the transceiver ALC input. Warm-up Procedure NOTE: The forward and reflected power LED bargraphs and GRID LEDs are peakresponding.
Radio Alpha Products Inc.
1. Tuning Up for Operation at 1,500 Watts RF Output Preset BAND, TUNE, and LOAD controls to the nominal positions given in Table 1, below*: Table 1 – Preliminary Tuneup Settings Band (MHz) Frequency (MHz) Tune Load 1.8 1.8 3.5 3.5 3.5 7 10 14 18 21 24 28 28 28 1.8 2.0 3.5 3.75 4.0 7.15 10.13 14.2 18.1 21.2 24.9 28.0 28.6 29.
7. Adjust LOAD control to place the illuminated TUNE LED at the “V” mark on the TUNE scale. 8. Repeat steps 6 and 7 at least twice. 9. Increase excitation until 99 output is about 1500 watts. 10. Repeat steps 6 and 7 at least twice. 11. Touch up TUNE for maximum power output. The ALPHA 99 is now correctly tuned to deliver 1500 watts RF output on SSB, CW, FSK, SSTV and FM. The TUNE LED normally fluctuates during modulation or keying.
6 Section Use and Maintenance Tubes The 4CX800A/GU74b tubes used in the ALPHA 99 are very rugged and normally operate with a large margin of safety. They should provide outstanding service for many years if not damaged by abuse - especially overdrive or blockage of cooling airflow. Allow at least twelve inches (31 cm) unobstructed clearance around the air intake and exhaust areas. Stacking equipment is not recommended. Never allow key-down plate current to exceed 1.
Cover interlocks are intended only as back-up protection against accidents. Never depend on them! Always disconnect the power cord from the AC mains before removing the cover! Interlock switches should never be disabled for any reason. Fuses Never replace any fuse with one of a different type or greater current rating. Blowing of one or both primary line fuses indicates that the maximum safe average power capability of the amplifier has been substantially exceeded or that an equipment failure has occurred.
32 Manual Alpha 99 Rev 1.
Preventive Maintenance The amplifier interior, particularly high voltage areas, should be cleaned with a vacuum cleaner and a soft bristle brush frequently enough to prevent visible accumulation of dust. In extremely dusty conditions it may be advisable to secure a thin air filter of the type used for window air conditioners across the air intake on the rear panel. The ALPHA accessory cooling fan also should be installed to insure adequate cooling airflow.
7 Section Troubleshooting Hints *NOTE: FCC rules do not permit new amateur amplifiers to be operable on 24-30 MHz as delivered within the US and possessions. As shipped to a US address, the amplifier is not operable on 21 MHz and above. Owners who send Alpha Power Customer Support a photocopy of their authorizing amateur license will promptly be provided information on “unlocking” 12 and 10 meter coverage. 99 will not turn on; nothing happens when ON switch is pushed.
1) Low voltage power supply problem. 2) Defect or damage on control board. Amplifier turns on but time delay will not complete; WAIT LED does not turn off. 1) Defect or damage in timing circuitry on control board. Amplifier turns on, time delay completes but amplifier will not transmit. 1) Open T/R control line from transceiver to RELAY jack. Radio Alpha Products Inc.
Amplifier transmits but red GRID LED often lights. 1) Amplifier overdriven or underloaded; reduce transceiver output and /or increase amplifier loading. 2) Load VSWR (reflected power) exceeds 200W. 3) Exciter output poorly controlled. External ALC may help. Amplifier operates but green GRID LED will not light and plate current is low; transceiver does not seem to be able to drive amplifier to its rated RF output power level.
microphone or key cable, or other unshielded station patch cables. 4) Poor station RF ground. Low frequency audio hum on transmitted signal. 1) Defective microphone cord (especially, broken ground lead). 2) Dynamic (magnetic) microphone located within about two feet of 99 power transformer. All dynamic microphones pick up some magnetically-coupled hum from the external field of nearby power transformers.
Figure 6 – Simplified Chassis Schematic Radio Alpha Products Inc.
Figure 7- Display Board ABX-X400 Radio Alpha Products Inc.
Figure 8 – Control Board ABX-X401 Radio Alpha Products Inc.
Figure 9 – Control Board ABX-X401 Page 2 of 2 Radio Alpha Products Inc.
Figure 10 – T/R Status Board, Multimeter Switch and Switch Matrix Board Radio Alpha Products Inc.
Figure 11 – Power Supply Board Radio Alpha Products Inc.
Figure 12 – HV Filter and Screen Supply Board Radio Alpha Products Inc.
Figure 13 – T/R Status Board and Multimeter Switch Radio Alpha Products Inc.
Figure 14 – Output Wattmeter Board Radio Alpha Products Inc.
Figure 15 – Center Partition Board Radio Alpha Products Inc.
Figure 16 – Tube Deck BCX-X413 Radio Alpha Products Inc.
Figure 17 – Wiring Harness Radio Alpha Products Inc.
ALPHA PRODUCTS WARRANTY RADIO ALPHA PRODUCTS, INC WARRANTS AS FOLLOWS EACH NEW ALPHA/POWER AMATEUR RADIO PRODUCT OF ITS MANUFACTURE, SOLD AND USED IN THE UNITED STATES, ITS POSSESSIONS, AND CANADA: 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).
UNDER PROVISIONS OF THE FEDERAL MAGNUSON-MOSS WARRANTY ACT, THIS WARRANTY POLICY IS CLASSIFIED AS A LIMITED WARRANTY. Radio Alpha Products Inc.
52 Manual Alpha 99 Rev 1.
