DGV-PA8406Amplifier

RF Concepts LLC

Click to zoom

Application Details

Equipment Class: AMP - Amplifier
Date of Grant: Oct 05, 2010
Application Purpose: Original Equipment
Date of Application: Oct 05, 2010
Equipment Note: Amplifier
Frequency Range: 50.00000000 - 54.00000000
Company: RF Concepts LLC
Country: United States

Documents & Files

Select a file to view

Document Text

Text extracted from the exhibit documents filed with the FCC. Open a document above to read the original.

Users Manual

1 Preliminary ALPHA 8406 6 Meter VHF LINEAR AMPLIFIER OPERATING MANUAL © 2010 RF Concepts, Inc 6185 Arapahoe Ave. Boulder, Colorado 80303 Phone 303 4739232 All rights reserved Specifications subject to change without notice - Rev. 1.1 October 4, 2010 2 Serial Number ______________________ Date Shipped _______________________ Software Version ____________________ Order Number ______________________ Index Specifications 4 Introductions 6 Quick Start Information 9 Station Engineering Considerations 11 Unpacking and Preparation 18 Theory of Operation 26 Operations and Maintenance 30 Trouble Shooting Hints 41 Glossary 46 3 Blank Page 4 Specifications 8406 6 Meter Amplifier Frequency 50-54 MHz Input drive Level 50 Watts Nominal Power Output 1500 watts SWR Tolerance 3:1 Duty Cycle 100 % Tubes (4CX1500B) Inter Modulation Level 34 dB minimum, Two Exciter Harmonics -72 dBc Mode of Operation CW, SSB, FM Input AC Voltage 100-240 Selectable AC Current <13 5mps @240 VAC @1500 watts Input Impedance 50 Ohms Output Impedance 50 Ohms RF Connectors “N” Female Cooling Forced Air Size 17.3” W x 7”H x 21.0”D Including Fan Space Weight 70 lbs., 31.8 kg T/R Relay Vacuum QSK Tuning /Band switching Manual Display Bargraph LED Interface USB Protection Against all common faults RF Bypass Level Less than 200 watts This amplifier meets or exceeds all technical specifications listed above. Technician ____________________________ Date ____________________ 5 Blank Page 6 1 Introduction 1.1 General Description Congratulations on your purchase of a professional quality Alpha 8406 amplifier! With proper installation and care, you can expect to enjoy your Amateur Radio hobby with this amplifier improving your signal for many years to come. Please study this manual carefully before operating your amplifier for the first time. The Alpha 8406 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. See our web site at www.rfconcepts.com or call 303-473-9232 for further information. 1.2 Amplifier Capabilities CAUTION: It is extremely important to thoroughly review the Installation and Operation sections of this manual before attempting to us the Alpha 8406. Failure to do so could result in serious damage that may not be covered under warranty.  Continuous RF Output. The 8406 is capable of 1.5 kW continuous RF output on all commonly used modes and on any authorized amateur frequency from 50-54 MHz  Compatibility with popular amateur transceivers and exciters. The 8406 requires approximately 50-65 W peak RF drive for 1.5 kW output.  Capable of full CW break-in, QSK and all digital modes when used with any appropriate transceiver.  Protective functions are built in. The control system incorporates protective functions that minimize the probability of accidental damage to the amplifier or its power tubes. In most cases, when one of the protective functions is “tripped,” the amplifier will go to Standby. 7 1.3 Shipping Information The Alpha 8406 amplifier ships in two heavy-duty cardboard cartons. One carton holds the power transformer and weighs 43 lb (20 kg) and the second carton contains the amplifier and weighs 38 lb.(17 kg). Both of these cartons are mounted on a wooden pallet and strapped down for a total weight of 98 lb.(45 kg). Alpha recommends that you retain the pallet and the cartons after installation in the unlikely situation that you need to ship the unit later. Contact RF Concepts at 303- 473-9232 for shipping advice and assistance. 1.4 Safety Information – Installation and Operation  Make sure the Alpha 8406 is located where there is good air circulation all around and on top of the cabinet. The unit may become hot during operation.  The Alpha 8406 weighs approximately 70 pounds when the transformer is installed. Use proper lifting techniques and two people when moving the amplifier. Note that amplifier should NEVER be transported with the transformer in place.  The Alpha 8406 is designed to meet international safety standards and FCC regulations. However, one should always remember that the equipment works with high voltages that can be LETHAL! This operating manual holds information, cautions and warnings that must be followed to ensure safe installation and operation. Read Chapter 1 before attempting to unpack or operate the Alpha 8406 amplifier. Warnings: What Not to Do  Never open the amplifier case without unplugging the unit from the wall outlet.  Always resist the temptation to immediately hit the ON button after the amplifier faults to power off.  Never touch an antenna during transmission.  Never attempt to turn on the amplifier without the cover securely in place (all attachment screws reinserted).  Never turn the amplifier back on after a hard fault without waiting at least 20 seconds.  Never allow liquids to enter the amplifier through the cover holes.  Never stick objects into holes in the case. Warnings posted in this manual should be read and thoroughly understood by users. Failure to perform procedures properly may result in amplifier damage, fire hazard, or electric shock. 8 1.5 Owner Assistance Technical Assistance from RF Concepts is available from several sources.  The RF Concepts web site is www.rfconcepts.com. Click on Support and follow the instructions. Many typical problems and their solutions are listed on this site. On this site you can get the following assistance:  Technical Support  Repair Information  Software Downloads  Manuals  Tech Tips  Legacy Equipment Information  FAQ’s  Alpha Forum You can email us for customer support at [email protected] or you can send your request by fax to 303-473-9660, or call us at 303-473-9232 9 2 Quick Start Information 2.1 Overview This section explains in brief the items you need to consider when setting up your Alpha 8406 amplifier. If you already have a well-designed shack and have used an am…

Text truncated - open the document above for the full version.

Block Diagram

Amplifier Block Diagram and RF Section Voltage and Current Levels

Cover Letter(s)

RF Concepts, LLC - 6185 Arapahoe Road - Boulder, CO 80303 - USA PHONE: 303.473.9232 - FAX: 303.473.9660 - WEB: rfconcepts.com Oct 6, 2010 Attached please find our submission for type acceptance of RF Concepts Alpha 8406 6M Linear Amplifier The attached package consists of the following items 01 - RF Concepts Alpha 8406 FCC Cover 02 - RF Concepts Alpha 8406 Form-731 03 - RF Concepts Alpha 8406 User ver 1.1 100410 04 - RF Concepts Alpha 8406 Theory of operation 05 - RF Concepts Alpha 8406 Tuning procedure 06 - RF Concepts Alpha 8406 FCC Label 07 - RF Concepts Alpha 8406 Block Diagram 08 - RF Concepts Alpha 8406 BOM 09 - RF Concepts Alpha 8406 Test Setup 10 - RF Concepts Alpha 8406 Photo Package 11 - RF Concepts Alpha 8406 Type Acceptance 092110 edited Ver 1.11 12 - RF Concepts Alpha 8406 Schematic Complete 13 - TIA-603C 100817-1608-1 REPORT If you have any questions feel free to contact me regarding this application Steve Farkas President RF Concepts, LLC [email protected]

External Photos

Alpha9500 Photo Package Page 1 Front of the 8406 Amplifier Alpha 8406 Photo Package Power Supply Side of the Amplifier With Transformer Right Side. Alpha 8406 Photo Package RF Tank and Tube Side of the Amplifier Left Side Alpha 8406 Photo Package Output Tank Alpha 8406 Photo Package Rear View Alpha 8406 Photo Package AC Relay PCB - Top Alpha 8406 Photo Package AC Relay PCB - Bottom Alpha 8406 Photo Package Five Volt Power Supply Board High Voltage Filter Board Alpha 8406 Photo Package Digital Display Board Alpha 8406 Photo Package High Voltage Board Alpha 8406 Photo Package Front Panel Inside View Alpha 8406 Photo Package Input Filter Board Alpha 8406 Photo Package Output Low Pass filter Alpha 8406 Photo Package Micro Processor Board Alpha 8406 Photo Package Tube Socket Alpha 8406 Photo Package TR-VSWR Board Alpha 8406 Photo Package FCC Lab Test Setup -1 Alpha 8406 Photo Package FCC Lab Test Setup -2

ID Label/Location Info

Drawing of Equipment ID Plate Note: The above drawing is not to scale. It is shown in expanded view for clarification purposes only. The FCC ID number will be in located on the outside rear panel of the Amplifier. The Proposed FCC ID is DGV-PA8406. The FCC ID will be printed in black block lettering on the gold-anodized chassis finish in a font size of eight-point (or greater). Model: AP 8406 FCC ID:DGV-PA8406 Serial Number: RF Concepts 6185 Arapahoe Ave. Boulder, CO 80303 USA Permanent label location will be on right side rear where temporary label is

Internal Photos

Operational Description

Theory of Operation 5.1 Theory of Operation - Overview The Alpha 8406 uses tetrode vacuum power grid tube (4CX1500B) as the amplifying devices. The main power supply is an unregulated transformer/rectifier/capacitor power supply for the high voltage (HV) and heater circuits. All other power supplies are regulated. The control circuit uses a microprocessor “in the loop” to monitor and control amplifier operation. There are 7 circuit cards in the amplifier. In addition to these, the tubes, tank circuit assembly, and transformer complete the main sections of the amplifier. These major blocks are described below. The 8406 amplifier includes a 5 V power supply that is mounted behind the front panel. Any time the amplifier is plugged into the mains power, this 5 V supply is active and there is power to the micro-controller on the main control board. This feature allows the amplifier to be turned on or off remotely as well as remote monitoring and debugging though a USB cable connected to a computer. 5.2 Tubes The amplifier is designed to use the 4CX1500B tetrode tube. The amplifier design uses these tubes well within their ratings. The tube is operated in Class AB1, with a plate voltage of 2,800V (nominal, full output, key down), a grid 1 voltage of -50 to -60 volts, and a grid 2 voltage of +230 volts. The tube has an inductance resistor in series with the cathode. This resistor stabilizes the tube bias and provides negative feedback, which improves linearity (and hence IMD performance). Electronic bias switching (EBS) increases the negative grid 1 voltage in pauses in speech or between Morse code elements. This reduces the standing bias on the tube, resulting in less waste heat, longer tube life and higher overall amplifier efficiency. The artifacts of EBS are not noticeable under normal communications conditions. 5.3 Output Tank Circuit The output tank circuit of the Alpha 8406 is designed to provide reliable high efficiency, low distortion performance in a very compact volume. The basic topology is “pi-C”, which provides harmonic attenuation adequate to meet the requirements of all countries globally that permits power outputs of 1,500 watts. The amplifier is designed to operate with only a single tube in order to reduce tube capacitance. 5.4 Tube Deck The tube deck is a mechanical assembly built around the tube deck PCB. The tube deck PCB has the tube socket mounted on it, as well as those critical circuit elements that need to be in close proximity to the tubes. The tube socket contains integral screen grid (grid 2) RF bypass capacitors. Also on this PCB is the input bypass relay. This relay is under microprocessor control and in one position switches the input RF to the tube and in the other it switches the input RF to the tube matching circuit. The tube is operated as a “swamped grid” tetrode design. The tube grid is tied at RF to a 50-ohm swamping resistor, which absorbs most of the input drive power. The RF voltage across this resistor is added to the grid 1 DC bias to provide the net low-impedance tube grid 1 bias. The RF impedance represented by grid 1 and its capacitance is compensated for by a series inductance to provide less than 2:1 SWR on each band at the amplifier’s input. 5.5 Mains Board The power supply functions are split between the mains board and the high voltage (HV) board. The mains board mostly deals with the primary side of the transformer. The various taps for the transformer primary are routed through this board and so is the AC line input. Relays on the mains board connect the AC line to the appropriate taps on the primary. One of 5 tap options is selected by using a 5-way jumper field. See section 4.3 for more details on how to set the jumper. Also on the mains board is a step-start circuit. This circuit consists of a relay and a resistor, which are time-sequenced to limit the inrush current into the amplifier when it is first turned on. When initially turned on, the tap relays operate from a voltage derived from resistors from the AC line. They hold via contacts on the trip relay on the HV board. The regulated minus 12 volt and minus 124 volt supplies are also located on this board. Many of the important voltages for the amplifier are brought to test points on this board. 5.5 High Voltage Board The main high voltage for the amplifier is created on this board using a full-wave bridge rectifier and a bank of capacitors. This power supply has two 10-ohm resistors, one in the positive (B+) lead, and the other in the negative return, which goes to ground. The combination of these two resistors limits the surge current in the case of a B+ arc. The voltage across the resistor in the negative return is used to monitor tube plate current in the control board. This voltage is also used to generate the “hard fault” condition. When the power supply current exceeds about 2 to 2.5 Amps, a relay operates to open the coil circuit of the mains tap relays on the mains board. When these relays release, the amplifier goes to the power-off state. This hard fault circuit operates independently of microprocessor control. The regulated screen supply is also located on this board. All power supply filter capacitors on this board have bleeder resistors which will discharge the capacitors in less than 60 seconds. If it is necessary to work on this board, it is nevertheless recommended that the discharged condition be confirmed with a voltmeter, due to the remote possibility of bleeder resistor failure. 5.7 Control Board The control board is the heart of the amplifier. It is based around a PIC microcontroller. This microcontroller has a built-in multi-channel analog-to-digital converter, which is used to monitor all the critical voltages and currents in the amplifier, as well as the input power and output forward and reflected power. It uses these converted values to control the amplifier’s operation and to drive the display board on the front panel. A USB port is provided for remote moni…

Text truncated - open the document above for the full version.

Parts List/Tune Up Info

ItemLine IDMemo TPX-X1701Alpha 8410, 9500, 8100, 99, 91b 240V 3.5KvA CSS Transformer - TPX-X170 ZLX-X2502Made in the USA label MSX-84033Sheet Metal, Wrapper, Top Cover 8410 ZFX-X1554Custom shipping foam set for ZCX-X155 boxes ZMX-X84105Alpha 8410 Manual SKX-X1146KNOB MULTIMETER /99 SKX-X1127Alpha 89 Tune or Load Control Knob VTX-X12084CX1500B Tube, VTX-X120 AHX-84609Main Chassis Assembly - 8406 CKD-102110Capacitor: .001uF 3kV CKM-102111CAP - .001uF 100V FHX-X10212FUSEHOLDER 3AG FLUTED RT ANGLE LITTLEFUSE 03420004H FSX-X11113FUSE 250V 2A Fast Acting FSX-X10914FUSE 20A/250V Ceramic HXA-X18115Feet/ Rear Round-Black HXA-X182169500 RIGHT FEET IHQ-104017MTG PAD- CAP 5.25 X 6.5" W/3/ IHQ-107618Skidpad, Transformer JCX-X12619PHONO JACK MSX-X02220Bail 14 W/ 1L 1R FOOT BUCKEY #1S000810H001" SIX-X10121SWITCH ROLLER SPDT 15A QC TERM MSX-840422Sheet Metal, Main Chassis 8410 AHX-8407238410 Blower Assembly JAX-X30224MTA .100 CONN 1x2P STRAIGHT POST WXX-X132251/8" HEATSHRINK TUBING XKX-X11926VINYL FOAM TAPE 1/8"X1"X AWX-8410278410 main Harness Assy JAX-X71028MTA .100 CONNECTORS CLOSED W/O TABS 10P RED JAX-X72129Conn, MTA, Recept, 2 Pin JAX-X70430MTA 4 Pin header JAX-X72031MTA RECPT 4PIN .100 22AWG HLX-X18332CONN FASTON FLAG 16-14GA HLX-X1363314-16GA .25 FAST-ON BLUE HLX-X1373418-22GA .25 QC FASTON RED HLX-X13835FASTON TERMINALS PIDG RECPT 22-18 AWG RED JAX-X72736CONN MTA .156 3POS PLUG HLX-X1253714-16GA PGBCK FML QUICK- WWX-X08138Wire, #22 WHITE 7-30 UL1061 PVC WWX-X03839Wire, #14 WHITE 600V TEFLON HUE 1419 WE WWX-X05140Wire, 18 white UL STYLE 1430 ahx-1516418410 Stack Board Assy HLX-X1374218-22GA .25 QC FASTON RED HLX-X14943#10 RING TONGUE TERM RED HNS-5013446-32 SS HEX NUT- SM PATT HSS-302445Hardware Screw 4-40 5/16 PP HSS-401946Screw, Mach, 6-32 X 5/16, PPSS HWA-X00147.125 ID X .250 OD SP WASH HWX-400148#6 Int LWSS HWX-402149#6 Flat Washer, Large Pattern HXF-413550Standoff, M/F, .25 X 2" HXF-413651Spacer, Nylon, 6-32 Thd, 2" JFX-X18252.100 WIRE MOUNT CONN 20P WRX-X11053FLAT CABLE 20 COND 28GA DRX-X13654DIODE HV Bridge ACX-X81555AC Mains Assy - 8410 CEX-3302-D56CAP 33UF 450V ELECT PW RADIAL CEX-3361-C57CAP 33UF 250V 20% RADIAL, NICHICON#UVZ2E330MHH CHX-1012-A58CAP 100PF 50V 5% 0805 SMD CERAMIC CHIP CHX-1015-C59CAP 100pF 500V 10% 1808 HIGH VOLTAGE ARC GUARD CER CHIP CHX-1023-B60CAP 0805 SMD CERAMIC CHIP CAP 1000PF 50V X7R 10% CHX-1034-B61CAP 0805 SMD CERAMIC SHIP CAP 0.01UF 50 VOLTS X7R 10% CHX-1035-C62CAP, 10000PF, 1000V, CERAMIC MULTILAYER CHX-1050-B63CAP 1.0UF 10V CERAMIC X7R 0805 CKD-1032-J64CAP 0.01uF 500V -20% +80% DZX-X11465Diode- Zener 1N5363BG 30V HLX-X22066LUG PDB MOUNT .250 H/99 JAX-X30467MTA .100 CONN 1x4P STRAIGHT POST JAX-X31768Headers 20P STRT 2 ROW GOLD JAX-X70869MTA 8 Pin Header JAX-X71370CONN MTA .156 FRCTN LK HDR STR 8P SQUARE POST TIN JAX-X72571Headers FRICTION LCK HDR 3P Straight Post tin JTX-X10072TEST POINT BLK .063 JTX-X10173TEST POINT, RED KDX-X14274RELAY PC MNT SPST-NO 30A 5VDC RFO-E102-C75RESISTOR 1k 2W Metal Oxide RFW-R25076RESISTOR R250 SOLDER LUG POWER 25WATTS 25 HMS 5% - RFW-R250 BCX-X81577PCB, Alpha 8410 Mains Board DRA-X01278DIODE SCHOTTKY 300MA CA SOT-23 DRX-X15679RECTIFIERS- BRIDGE 4A 600V JAX-X31280MTA .100 CONN 1x12P STRAIGHT POST CDX-1021-A81CAP,CER DISC,1000PF,1KV ACX-X81682HVPS Assy - 8410 CEX-106283CAP- 10UF/50V ELECT. VERT CEX-3311-C84CAP 330UF 450V ELECT KMQ SNAP CEX-3302-D85CAP 33UF 450V ELECT PW RADIAL CHX-1025-B86CAP CER 1000PF 500V X7R 0805 CHX-1034-B87CAP 0805 SMD CERAMIC SHIP CAP 0.01UF 50 VOLTS X7R 10% CHX-1035-C88CAP, 10000PF, 1000V, CERAMIC MULTILAYER DRX-X12889DIODE 1000v 1A DZA-X01490TVS DIODES 400Vso 447VBR 2.3A DZX-X10391DIODE ZENER DIODE 1N4746A 18V DZX-X11492Diode- Zener 1N5363BG 30V DZX-X12593DIODE ZENER 1N751A 5.1V DZX-X15694DIODE ZENER 5W 3.3V DO41 DZX-X15795DIODE-ZENER 9.1V 5W HLX-X22096LUG PDB MOUNT .250 H/99 JAX-X31797Headers 20P STRT 2 ROW GOLD JAX-X606986 PIN MTA JACK-18GA .156 KDX-X14099RELAY LATCHING 2A 5VDC PC MNT QTX-X109100TRANSISTOR FAIRCHILD 2N3906TA QTX-X177101TRANSISTOR 600V CASE (TO-220AB 10V RFC-C1004-A102RES MF 1MOHM .50W 350V RFF-B472-C103RES-4.7K 1/4W 5% CARB FLM RFM-B1001-A104RES 1 OHM METAL FILM 1/4 WATT 1% RFM-B1002-A105RES 10K OHM METAL FILM 1/4 WATT 1% RFF-B471-C106RES-470 1/4W 5% CARB FILM RFO-D222-C107resistor RFO-E154-D108RES 150K0HM 5% RFO-H220-C109Res, MO, 5W, 22 ohms RFW-E101-C110WIREWOUND RESISTOR 100 OHM 5% 2W RFW-H601111600 ohm 5 W wire wound RFW-R100112SOLDER LUG POWER RESISTORS 25WATTS 10 OHMS 5% RVK-1033-D113POT 10K OHM SQ CERMET SIDE JTX-X100114TEST POINT BLK .063 JTX-X101115TEST POINT, RED UAX-X044116IC OP AMP CMOS SINGL MICRO 8SOIC CDX-2221-C117CAP 2200PF 6K VOLTS 20% .375 L.S. RADIAL MSX-8417118Alpha 8400 Bottom Cover ACX-X846119Silver plated Tank Coil Assembly - 8406 IHC-8460120Tank Coil Unplated Assembly - 8406 XSX-X122121Solder, Silver-bearing, .062". 1 lb XTX-X1051223/16 OD COPPER 50FT ROLL AHX-8462123Center Partition Assy - 8406 JBX-X113124Terminal Block, 4 Term HSS-40311256-32 X1/2 S/S PPHMS HWX-4001126#6 Int LWSS RFW-P003-A127ALUMINUM POWER REISTORS .03 OHM 1% HSS-3024128Hardware Screw 4-40 5/16 PP HWX-3003129#4 INT LWSS HXF-X148130Standoff Hex 6-32 Thd Alum .750" HSS-4019131Screw, Mach, 6-32 X 5/16, PPSS HSN-9000132Screw, Nylon, 8-32 X 1/8" MSX-X658133MSX-X658_B Crow bar contact spring safety interlock IHQ-1054134HV Crowbar Insulator STNOFF HGX-X102135HARDWARE RUBBER GROMMET .312 WWX-023136Wire, HV Red HLX-X13613714-16GA .25 FAST-ON BLUE HSS-40511386-32 X 7/8 PPSS HNS-50131396-32 SS HEX NUT- SM PATT HSS-602214010-32 X 1/2 SSPPHMS HWX-6009141.062 THK-.194 ID-#10FIBER ABX-X412142High Voltage Filter Assy - 9500 CDX-2022143CAPACITOR .002uF 3KV DISC HLX-X220144LUG PDB MOUNT .250 H/99 LCX-X101145Choke 15uH L005 BCX-X412146PCB, HV DC FILTER HWX-6005147#10 INT LW SS JBX-X114148TERMINAL BLOCKS MARKING STRIP 4 TRM CTX-6002149Cap, Air Var, 46 pF, 3.7 KV, 12 mm shaft CTX-6003150Cap, Air Var, 46 pF, 3.7 KV, 112 mm shaft ABX-X4386151Output Board assy - 8406 DZX-X155152DIODE ZENER 5W 5.6V DO41 DRA-X009153DIODE…

Text truncated - open the document above for the full version.

Parts List/Tune Up Info

6.3 Initial Setup and Tuning 6.3.1 Control Functions The following chart shows the controls that allow you to adjust and monitor the amplifier. BAND Used to select amateur band desired (in MHz). TUNE Sets output tank circuit to resonance within each band. 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. Higher frequencies tend to load more toward the “100” end of the dial scale and lower frequencies toward the “0” end. 6.3.2 Tune-Up The objective of tune-up is to adjust the amplifier (and the drive applied to it) to obtain optimum efficiency and linearity at the desired output power. Any linear amplifier must be adjusted for optimum efficiency and linearity at each specific power level. If operation at higher power is then attempted without appropriate readjustment, the result will be flat topping also known as “splatter,” and (usually) excessive amplifier grid current. If operated at a much lower power level than it has been adjusted for, the amplifier’s efficiency decreases considerably. Recommended practice is to tune first into a dummy load or artificial antenna, then connect the antenna and make any slight final adjustments that may be needed. 6.3.3 Grid Current Information The ALPHA 8406 operates in Class AB1 when delivering maximum output power consistent with excellent linearity. A small amount of grid current flows and the green GRID MIN LED illuminates as drive approaches the optimum level. The green GRID LED will flicker on SSB voice peaks and illuminate under CW/SSTV/RTTY carrier conditions. As overdrive approaches, grid current increases rapidly and the red GRID MAX LED illuminates. At maximum output and efficiency, the red LED lights dimly; full illumination of the red LED indicates overdrive and must be avoided. If the red LED lights up before the desired value of plate current and/or against grid current fluctuations. On SSB, optimum output consistent with good linearity, occurs when the green forward LED’s illuminates on most voice peaks and the red LED flickers dimly on only the highest peaks. Excessive grid current results from overdrive and/or inadequate loading. The solution is to restrict drive, and/or increase amplifier loading. The 8406's 4CX1500B tube is well protected and these adjustments tend to be less critical than in many other amplifiers. Grid bias is stabilized against grid current fluctuations. 6.3.4 ALC The 8406 grid current limiting circuits provide substantial tube protection against possible damage, therefore no ALC control is necessary. It is only necessary to set the drive power from the radio as detailed in this manual. 6.3.5 Turning On The Amplifier Please Note: Every time the ALPHA 8406 is powered up, there is a built-in 180 second warm up wait. 1. Place the OPR/STBY switch to STBY (standby). 2. Rotate the multimeter selector switch to HV. 3. Depress the POWER/ON switch. The fan and blower should immediately begin to operate. If there is no air flow from the amplifier and no sound of blower operation, immediately turn the amplifier off and investigate. 4. Within two seconds, the HV display should be all the way to the right, certainly above 2,500 Volts. If it is lower than this, investigate further- perhaps the primary taps are not correctly set. 5. At this time the red LED representing 1800 W output power is illuminated, indicating 180 seconds countdown remaining (1800/10 = 180 seconds). As the timer counts down, the remaining time will be indicated by the currently illuminated LED on the power output bar graph moving to the left. 6. Move the multimeter switch to the Ip position. There should be no current indicated, and this should be true during the entire period the amplifier is warming up. Leave the switch in the Ip position during amplifier warm up. The “Wait” LED will be blinking about twice per second, indicating that warm up is still in progress. The FAULT, OPER and STBY LED’s should not be illuminated.

RF Exposure Info

15 ¼ Wave Vertical Antenna Interpretation of Results 1. The power value entered into these calculations should be the average power seen at the antenna and not Peak Envelope Power (PEP). You should also consider feedline loss in calculating your average power at the antenna. 2. If you wish to estimate the power density at a point below the main lobe of a directional antenna, and if the antenna's vertical pattern is known, recalculate using the antenna's gain in the relevant direction. 3. Please also consult FCC OET Bulletin 65 Supplement B, the Amateur Radio supplement to FCC OET Bulletin 65. It contains a thorough discussion of the RF Safety regulations as they apply to amateur stations and contains numerous charts, tables, worksheets and other data to help determine station compliance. The above calculation is for a vertical ground plane antenna at 20 feet elevation feed with a short piece of coax with the station located just below the antenna. Minimum safe distance is represented in Red. The antenna is located at ten feet above ground. Calculation Results Average Power at the Antenna 1500 watts Antenna Gain in dBi 2 dBi Distance to the Area of Interest 100 feet 30.48 meters Frequency of Operation 50 MHz Are Ground Reflections Calculated? Yes Estimated RF Power Density 0.0522 mW/cm 2 Controlled Environment Uncontrolled Environment Maximum Permissible Exposure (MPE) 1.005 mW/cm 2 0.205 mW/cm 2 Distance to Compliance From Centre of Antenna 22.8821 feet 6.9745 meters 51.1041 feet 15.5765 meters Does the Area of Interest Appear to be in Compliance? yes yes

Schematics

!" #$$ $! ! $% & '##!! # % %$ ##$ # $ # #' ## % ## $##!'### # ""() """() #* $+ , # # ! RF POWER REF POWER MULTI METER Display Brightness Bar Graph Driver ! , $ '" ' # % ' # # #% "" !-' ) ) ) ) %$ R1 10K ! R3 - # - # #! # # # , # # #. # '" %$ ! ( /! , ' ' ' ' ' ' ' & " 0! ( , ( , ( , ( , # # #! # # ## # # # # # # # #! # ## # # #! # # # ######!## # # # # # # # #! # # ! !" ###$%&""" ##$%&"" ! ' ! ' '(' ( ' ' ) ! ! ! #!*"+,&-" !*"+,&- ' ( ."" . ! ! ( ' (." #&# ." "%"%"."%"%". #&#// #&#. #&#. #&#. #&#. """"" ""0 ""0 """"" …

Text truncated - open the document above for the full version.