Alpha Radio Products 8410 Operating Manual

Alpha Radio Products 8410 Operating Manual

Hf linear amplifier

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ALPHA 8410
HF LINEAR AMPLIFIER
OPERATING MANUAL
© 2009 Alpha Radio Products, Inc
6185 Arapahoe Ave.
Boulder, Colorado 80303
Phone 303 4739232
All rights reserved
Specifications subject to change without notice - Rev. 102
1

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Summary of Contents for Alpha Radio Products 8410

  • Page 1 ALPHA 8410 HF LINEAR AMPLIFIER OPERATING MANUAL © 2009 Alpha Radio Products, Inc 6185 Arapahoe Ave. Boulder, Colorado 80303 Phone 303 4739232 All rights reserved Specifications subject to change without notice - Rev. 102...
  • Page 2 Serial Number ______________________ Date Shipped _______________________ Software Version ____________________ Order Number ______________________...
  • Page 3: Table Of Contents

    Index Specifications Introduction Quick Start Information Station Engineering Considerations Unpacking and Preparation Theory of Operation Operation and Maintenance Trouble Shooting Hints Glossary...
  • Page 4: Specifications

    Specifications Frequency 1.8-29.7 KHz Input drive Level 50 Watts Nominal Power Output 1500 watts SWR Tolerance 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...
  • Page 5: Introduction

    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.
  • Page 6: Shipping Information

    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.
  • Page 7: Owner Assistance

    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...
  • Page 8 Blank Page...
  • Page 9: Quick Start Information

    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.
  • Page 10 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)
  • Page 11: Station Engineering Considerations

    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.
  • Page 12 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.
  • Page 13: Coax And Connectors

    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.
  • Page 14 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...
  • Page 15: Unpacking And Preparation

    It is recommended that the power transformer be installed when the amp is at or near the place it is to be used. The chassis of the 8410 is designed for the mechanical loads it experiences when the amplifier is on a flat surface with the tilt-bail up or down. If the amplifier is tilted too far, such that the transformer is cantilevered or “hanging out”...
  • Page 16: Power Cord Connections

    ALWAYS use grounding type AC connectors which conform to local codes and ensure that the green wire in the Alpha 8410 power cable is wired only to the AC mains safety ground (or to neutral, as may be necessary with a 240V circuit configured 120V-N-120V without a separate ground, commonly found in the US).
  • Page 17 P max = (V x I ) / 2.3 lineline For example, if the Alpha 8410 operates from a circuit that is capable of delivering 120 V AC at a maximum current of 20A, with no other loads connected to the circuit, maximum peak RF output possible without tripping the 20A breaker (or fuse) is approximately: P o max = (120V x 20A) / 2.3 = 2400/2.3 = 1043 W...
  • Page 18 company and ask if they can reduce your line voltage. If this is not possible, you may want to consider placing your own step-down transformer in line between the AC outlet and the amplifier. If this is necessary, a transformer with at least 4-kVA rating is required, due to the nature of the current waveform in the primary.
  • Page 19 FIGURE 4-2-2 Amplifier Rear Air Inlet Key line Input/Output RF Input RF Output USB Input AC Fuses AC Cord Chassis Ground...
  • Page 20 Input AC tap settings can be made by moving the flying lead to the marked AC spade posts marked in the appropriate voltages. The proper taps must be made before the AC power is applied. When making changes make sure the amplifier is unplugged.
  • Page 21: Replacing The Amplifier Cover

    “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 8410 to follow the CW keying. If a T/R timing problem is suspected, connect the CW keyer to the RELAY jack on the Alpha 8410, and connect a cable from KEY OUT on the amplifier to the keying input of the transmitter.
  • Page 22 4.5.3 ALC The Alpha 8410 does not generate or use ALC voltages to control an exciter. For proper operation the exciter transceiver should have its power output set so as not to over drive the amplifier input. Today’s modern transceivers have very good power output limiting.
  • Page 23: Theory Of Operation

    The two tubes are operated in parallel, and the Alpha 8410 is designed with the expectation that a matched pair of tubes will be used in the amplifier. Alpha matches tubes received from the supplier to within 10% for power output and gain when operated in a standardized test fixture.
  • Page 24 multi-function tap selectors, which simultaneously select band taps on the inductors and include varying amounts of capacitance to provide band-spread on the tune and load capacitors. These four wafers are in the RF tank area. A variable resistor inside the front sub-chassis and is used by the control board to determine which band the user has selected.
  • Page 25: Control Board

    A USB port is provided for remote monitoring and is found on the back of the Alpha 8410. The USB driver for the amplifier is provided on the CD shipped with the unit or can be found on the Alpha website at www.alpharadioproducts.com...
  • Page 26 5.9 Center Partition Board This contains the RF decoupling circuit on the B+ line as well as the “crowbar” safety circuit. This safety device consists of a piece of spring metal, which shorts out the B+ line when the top cover of the amplifier is removed. Do not defeat this safety circuit.
  • Page 27: Operation And Maintenance

    You must set the transceiver output power properly. Virtually all damage to has resulted directly from severe overdrive. The ALPHA 8410 requires about 50 W drive for full rated output. Damage caused by applying several times rated drive power to the ALPHA 8410 will not be covered under warranty.
  • Page 28 Fault type 4 HV LED is blinking. This indicates a reflected power fault. The 8410 is set up to trip when the reflected power exceeds approximately 300 watts. At 1,500 watts output, this would represent an The fault type codes above are also reported in the amplifier telemetry data via the serial or USB ports on the rear of the amplifier.
  • Page 29 Alpha 8410. Nevertheless, if the system SWR is below 2:1, the additional RF power loss of an antenna tuner can be avoided by tuning the 8410 into the slight mismatch. There is no advantage to using a tuner to “tweak” the last bit of SWR - in fact you will lose power this way.
  • Page 30: Control Functions

    6.2 Transceiver Connections The Alpha 8410 “relay” jack has approximately 12 V on it. When pulled all the way to ground, a current of 10 mA flows. Consult your transceiver manual for additional information on how to connect to an external amplifier.
  • Page 31: Turning On The Amplifier

    6.3.5 Turning On The Amplifier Please Note: Every time the ALPHA 8410 is powered up, there is a built-in 180 second warm up wait. 1. Place the OPR/STBY switch to STBY (standby).
  • Page 32 When the warm up delay is complete, the WAIT LED will extinguish and the OPR or STBY lights will stop blinking. Put the OPR/STBY switch to OPR and the Alpha 8410 is now “ready”.
  • Page 33 Alpha Radio Products recommended tune up procedure. “Dip and Load” Method Tuning up for Operation at 1,500 W RF Output. Preset BAND, TUNE, and LOAD controls to the nominal positions given in your amp’s specific tune up table or Table 6.3: Note: Final TUNE and LOAD settings will vary with the operating frequency, antenna characteristics and power level.
  • Page 34 9. Repeat steps 6 and 7 at least twice. 10. Touch up the TUNE control for maximum power output. 11.The ALPHA 8410 is now correctly tuned to deliver 1,500 W RF output on SSB, CW, FSK, SSTV and FM. The TUNE LED normally fluctuates during modulation or keying.
  • Page 35: Normal Use

    6.4 Normal Use 6.4.1 Tubes The VTX-X118 tubes used in the Alpha 8410 are supplied as a matched pair. They 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 – such as overdrive or blockage of cooling airflow.
  • Page 36 AC power from the amplifier, then determine and correct the cause of the trip before turning the 8410 on again. This “hard fault” trip circuit does not rely on the microcontroller for it’s operation, and will protect the amplifier even if the processor has been damaged or is malfunctioning.
  • Page 37 There are no user-accessible lubrication points in the amplifier. Do not apply oil or grease to any of the components. The exterior of the ALPHA 8410 may be cleaned with a mild household liquid detergent. Do not use chemical solvents, as these may severely damage the front panel or cabinet finish.
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  • Page 39: Troubleshooting Hints

    7 Troubleshooting Hints 7.1 Normal Troubleshooting 8410 will not turn on; nothing happens when ON switch is pushed. Problem Correction 1) External AC wiring, fuse or circuit Check & correct wiring, replace fuse, or breaker may be open. reset circuit breaker.
  • Page 40 Amplifier turns on but no multimeter indication; other LED bargraphs are operative. Problem Correction 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. Problem Correction 1) Defect or damage in timing circuitry on...
  • Page 41 STBY to OPR. Problem Correction 1) RELAY (T/R) control cable from Check T/R control cable to make sure it is transceiver is shorted. switching properly. Replace if needed. 2) Transceiver locked in transmit Make sure transceiver is properly switching between transmit and receive. See transceiver’s User’s Manual for assistance.
  • Page 42 Problem Correction 1) If the amount of drive required to Contact Alpha Customer Support to see if maintain 1,500 watts is steadily increasing, this is an tubes need replacing. indication that the tubes are probably aging.
  • Page 43: Glossary

    ARRL-American Radio Relay League AWG-American Wire Gauge CW-Continuous wave dB-Decibel EBS-Electronic bias switching Exciter-The radio that provides RF drive for the 8410 to operate FCC-Federal Communications Commission FM-Frequency modulation FSK-Frequency-shift keying HF-High frequency (3 to 30 MHz) HV-High voltage...
  • Page 44 US – United States. VAC – Volts of alternating current. VDC – Volts of direct current. VSWR – Voltage Standing Wave Ratio Manual written by: Mike Higgins - K6AER...
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