ALPHA 8100
Contents
1. 6 3 5 Turning 0n The Amplifier Please Note Every time the ALPHA 8100 is powered up there is a built in 150 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 For about two seconds the bar graph displays and the LEDs on the front panel will be lit randomly as the microcontroller goes through its start up sequence 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 After the two second period 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 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 warmup The Wait LED will be blinking about twice per second indicating that warmup is still in progress The FAULT OPER and STBY LEDs should not be illuminated CAUTION EXHAUST AIR MUST BE DETECTABLE FROM BOTH TOP VENTS ALPHA 8100 OPERATING MANUAL www alpharadioproducts com 40 If exhaust air is not coming from the top vents TURN OFF the amplifier immediately and verify that the exhaust chimneys are properly posit2. is an expensive solution but is a good way to stabilize primary voltage Note If you intend to operate the amplifier on any of the 90 130V settings the two lower 2 amp fuses on the rear panel will have to be changed to 5 amp to allow for the increased in rush current ALPHA 8100 OPERATING MANUAL www alpharadioproducts com 04 Figure 4 3 AC Power setting With the top cover removed the primary voltage taps are located on the top of the Mains Board which is between the transformer and the front panel There is a row of 5 fast on connectors J1 through J5 and a flying jumper connector which mates with them See Figure 4 3 There are 5 nominal primary voltages which cover all the line voltages normally encountered around the world Selecting the appropriate tap for your situation will optimize amplifier performance safety and lifetime The nominal mid range voltage for each tap is printed on the Mains Board circuit board These voltages are 100 120 200 220 and 240 Volts The acceptable line voltage for each tap is the center voltage plus or minus 10 Volts One of these taps is suitable for any of the nominal line voltages encountered worldwide ALPHA 8100 OPERATING MANUAL www alpharadioproducts com 2D 4 4 Complete the Transformer Installation 4 4 1 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 eart
3. transceiver 6 1 2 Dealing with Faults The ALPHA 8100 faults into STBY or OFF when unsafe operating conditions occur This is shown when the amplifier changes from the OPR LED being ON to the Fault and STBY LEDs turning ON instead soft fault or when the amplifier shuts off completely hard fault ALPHA 8100 OPERATING MANUAL www alpharadioproducts com 34 One of four situations will typically result in a fault e Incorrect gain Output too low or too high for the input power supplied e High reflected power SWR e Incorrect plate voltage too high e RF arc in output circuit including antenna If the 8100 encounters unsafe operating conditions it enters a protective Fault mode When this happens the tubes are biased off and the relays are placed in the bypass mode so that RF from the radio goes directly to the antenna The FAULT LED on the front panel will flash on and off for a period of about 4 seconds after which the amplifier will attempt to go back into OPERATE mode unless the OPER STBY switch has been placed in the STBY position This 4 second period can be shortened by toggling the OPER STBY switch While the FAULT LED is flashing the Ip and HV LEDs are used to indicate which of the four fault conditions caused the amplifier to enter fault mode Fault type 1 Neither Ip nor HV LEDs are lit Output relay did not close This fault will rarely be encountered but if it is it must be investigated further
4. KEY OUT on the amplifier to the keying input of the transmitter 4 5 3 ALC The Alpha 8100 does not generate or use ALC voltages to control an exciter ALPHA 8100 OPERATING MANUAL www alpharadioproducts com 27 Key In line from RF output to antenna radio 1500 watts Key Out line op tional to radio RF input from radio 50 60 watts ALPHA 8100 OPERATING MANUAL www alpharadioproducts com 28 ALPHA 8100 OPERATING MANUAL www alpharadioproducts com 29 5 Theory of Operation 5 1 Theory of Operation Overview The Alpha 8100 uses tetrode vacuum power grid tubes 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 8 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 5 2 Tubes The amplifier is designed to use two GU74B tetrode tubes The Svetlana Company of St Petersburg Russia manufactures these tubes The amplifier design uses these tubes well within their ratings At the time of manufacture these tubes are available as new military surplus NMS devices According to Svetlana the 4CX800A tube is a direct commercial rep
5. immediately as continued operation with this fault could cause additional damage to the amplifier Fault type 2 Ip LED is blinking This indicates that the plate current in the tubes exceeded 1 5 amps This could be caused by the amplifier being mistuned or by overdriving the amplifier If neither of the above is the case then a problem in the bias control circuitry may be indicated Fault type 3 Both Ip and HV LEDs are blinking This indicates that the gain of the amplifier has fallen below 10 dB This is an important safety feature of the amplifier as many different problems in the amplifier or with its operation can be detected as a drop in gain To avoid this fault occurring while the amplifier is being tuned up the gain fault detection is disabled when drive power to the amplifier is below approximately 20 watts This allows correct initial amplifier tuning to be achieved before going to full power Fault type 4 HV LED is blinking This indicates a reflected power fault The 8100 is set up to trip when the reflected power exceeds approximately 250 watts At 1 500 watts output this would represent an SWR of approximately 2 4 1 Possible causes for this fault are in the antenna No antenna could be ALPHA 8100 OPERATING MANUAL www alpharadioproducts com 30 connected or the wrong antenna for the selected band could be connected In a few cases low pass filters connected between the amplifier and the antenna have failed due to th
6. 0 power magnetically coupled hum from the external transformer field of nearby power transformers In cases where objectionable hum is experienced while using the 8100 and popular microphones such as the Heil series the problem usually can be resolved by keeping the microphone at least 18 to 24 inches from the front of the amplifier and ensuring that transceiver mike gain and speech processing levels are not adjusted to exceed 10 dB In rare cases it may be necessary to use a ceramic or condenser type microphone Grid bias is unexpectedly decreasing 1 Nominal grid bias current is 380 mA If Contact Alpha Customer Support to see if the normal bias is decreasing the tubes are tubes need replacing probably aging Required drive to maintain 1 500 W is steadily increasing 1 If the amount of drive required to maintain Contact Alpha Customer Support to see if 1 500 watts is steadily increasing this is an tubes need replacing indication that the tubes are probably aging 7 2 Troubleshooting Using the Serial Port Information about the amplifier s setup calibration and current operational condition can be obtained through the serial port Use HyperTerm at 115 2kBd 8N1 Two sentences are produced by the amplifier These are as follows ALPHA 8100 OPERATING MANUAL www alpharadioproducts com Identification Sentence Send I to cause the unit to emit a sentence of this format SAPA00 8100074300 1 08 01
7. 546 01714 01397 00297 04540 00000 005 13 00970 00393 00000 0100 0 0025 0200 010 128 074 5621 Start or flag character This can be used by an external program to locate the start of the sentence as it is never used elsewhere The checksum calculation begins after this character APAOO Short for Alpha Power Amplifier type 00 This indicates the sentence is from an Alpha product an amplifier Type 00 sentences are frequently used for identification This is the beginning of the payload portion of the sentence 8100074300 This is the amplifier s manufacturers serial number 1 08 Code version 01546 Forward power meter slope 01714 Forward power engineering units slope 01397 Reflected power slope 00297 Input power slope 04540 Plate voltage slope 00000 Plate voltage offset 00513 Plate current slope 00970 Plate current offset 00393 Grid current power slope 00000 Grid current offset ALPHA 8100 OPERATING MANUAL www alpharadioproducts com 32 01000 Gain slope 0025 Green LED threshold tenths of a mA 0200 Red LED threshold tenths of a mA 010 EBS switching threshold tenths of a watt 128 EBS DAC setting 074 Bias DAC setting End of the payload portion of the sentence The checksum calculation ends with the last character preceding the 5621 Fletcher checksum FCS of the payload portion The FCS is a two byte quantity calculated over the payload portion of the sentence according to the following
8. 8100 output will be approximately 300 500 W 5 Adjust the TUNE control to deflect the GAIN LED maximum rightward 6 Adjust the LOAD control to place the illuminated GAIN LED in between the white lines on the GAIN scale 7 Repeat steps 5 and 6 at least twice 8 Increase the excitation power until the 8100 output is about 1500 W 9 Repeat steps 6 and 7 at least twice 10 Touch up the TUNE for maximum power output 11 The ALPHA 8100 is now correctly tuned to deliver 1500 W RF output on SSB CW FSK SSTV and FM The GAIN LED normally fluctuates during modulation or keying Illumination of the first red LED on the RF OUTPUT bargraph indicates output has exceeded 1500 W The GAIN LED may vary during standard opertaion especially SSB This is normal ALPHA 8100 OPERATING MANUAL www alpharadioproducts com 43 6 4 Normal Use 6 4 1 Tubes The 4CX800A GU74b tubes used in the ALPHA 8100 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 Allow at least three to four inches 10 cm of unobstructed clearance around the air intake and exhaust areas Stacking equipment on top of the amplifier is not recommended Never allow key down plate current to exceed 1 5 A for more than one or two seconds If you do and a plate current trip occurs it will automatic
9. ALPHA 6100 HF LINEAR AMPLIFIER OPERATING MANUAL O 2006 Alpha Radio Products Inc All rights reserved Specifications subject to change without notice ALPHA 8100 OPERATING MANUAL www alpharadioproducts com ALPHA 8100 OPERATING MANUAL www alpharadioproducts com Table of Contents 1 introduction 7 1 1General Description 7 1 2 Amplifier Capabilities 8 1 3 Shipping Information 8 1 4 Safety Information Installation and Operation 8 1 5 Owner Assistance 9 2 Quick Start Information 11 2 1 Overview 11 2 2 Station Engineering Considerations Checklist 11 2 3 Preparation 11 2 4 Unpacking 12 2 5 Operation 12 3 Station Engineering Considerations 13 3 1 Overview 13 3 2 AC Power Source 13 3 3 Air Flow 13 3 4 Antennas 14 3 5 Coax and Connectors 15 3 6 RF Safety 15 4 Unpacking amp Preparation 17 4 1 Unpacking 17 4 2 Installing the Power Transformer 17 4 2 1 Install the Power Transformer 18 4 2 2 Connecting the Transformer Power Plugs 20 4 2 3 Power Cord Connections 21 4 2 4 Important Information About Operation from 90 130V AC 21 4 3 AC Primary Connections 22 4 4 Complete the Transformer Installation 25 4 4 1 RF Grounding 25 4 4 2 Replacing the Amplifier Cover 25 ALPHA 8100 OPERATING MANUAL www alpharadioproducts com 4 4 4 3 Blower Preparation 25 4 5 Amplifier Station Interconnections 25 4 5 1 Coaxial Cable Types amp Connectors 25 4 5 2T R Control Cable 26 4 5 3ALC 26 5 Theory of Operat
10. F output to the ALPHA 8100 RF INPUT connector with 50 ohm coaxial cable ALPHA 8100 OPERATING MANUAL www alpharadioproducts com 26 RG 58C U or equivalent A 6 ft cable is supplied for this purpose Coaxial cable from the 8100 RF OUTPUT connector to the 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 as it is not rated for 1500 watts 4 5 2 T R Control Cable The Alpha 8100 has a full break in vacuum relay QSK system requiring only the normal interconnection when used with a modern QSK transceiver The Alpha 8100 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 normally open in receive and closed in transmit Shielded wire should be used for the T R control cable The Alpha 8100 end must be fitted with a common phono RCA type plug and the other end with a connector suitable for the transceiver The T R relay contact must close before application of RF drive The Alpha 8100 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 8100 to follow the CW keying If a T R timing problem is suspected connect the CW keyer to the RELAY jack on the Alpha 8100 and connect a cable from
11. MANUAL www alpharadioproducts com 10 e FAQs e You can e mail us for customer support at service alpharadioproducts com or you can send your request by fax to 303 473 9660 ALPHA 8100 OPERATING MANUAL www alpharadioproducts com 11 2 Quick Start Information 2 1 Overview This section explains in brief the items you need to consider when setting up your Alpha 8100 amplifier If you already have a well designed shack and have used an amplifier before please review the items below to make sure you have considered all the critical items for proper installation and operation If you are using an amplifier for the first time please skip this section and go to sections 3 4 and 5 for a more detailed explanation of how to set up your shack for maximum safety and operating enjoyment If you have installation questions do not hesitate to contact Customer Support We much prefer to address questions prior to power up 2 2 Station Engineering Considerations Checklist Make sure you have properly addressed the following concerns Section 2 3 below before installation of your Alpha 8100 amplifier If you are unsure of any of these items please read the noted sections carefully 2 3 Preparation __ 220V AC Power in shack Section 3 2 __ Amplifier placed with proper airflow Section 3 3 __ Antenna ready for 1 500W Section 3 4 __ Adequate RF cabling Section 3 5 ALPHA 8100 OPERATING MANUAL www alpharadioproducts co
12. VOLT RATED FUSES for 190 220 VAC service 25 amp fuses may be used with caution for line voltages of 90 130V The slow blow fuse F3 located below the primary line fuses may prevent damage to the step start resistors and HV rectifiers in the event of abnormal turn on conditions or HV faults If the AC interlock is defeated and primary power is applied while the HV crowbar is closed the step start fuses will normally blow CAUTION DAMAGE RESULTING FROM USE OF A FUSE OF INCORRECT SIZE OR TYPE WILL NOT BE COVERED UNDER WARRANTY AND MAY VOID THE WARRANTY 6 4 4 Plate Overcurrent Relay This relay will quickly turn off the amplifier in the event of grossly excessive plate current or fault in the high voltage circuitry The relay will not prevent tube or other damage due to either short or long term overdrive or improper tuning It is the operator s responsibility to ensure safe tuning drive and general operating conditions Should the overcurrent relay trip remove AC power from the amplifier then determine and correct the cause of the trip before turning the 8100 on again This hard fault trip circuit does not rely on the microntroller for it s operation and will protect the amplifier even if the processor has been damaged or is malfunctioning 6 4 5 Idling Plate Current and Electronic Bias Control tbs Idling plate current of the ALPHA 8100 is approximately 350 to 400 mA during full power transmission A detector senses RF drive an
13. a very compact volume The basic topology is pi L which provides harmonic attenuation adequate to meet the requirements of all countries globally that permit power outputs of 1 500 watts Band switching is under manual control and is accomplished by a four wafer band switch Three of these wafers are used as 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 three wafers are in the RF tank area The fourth wafer is inside the front sub chassis and is used by the control board to determine which band the user has selected 5 4 Tube Deck The tube deck is a mechanical assembly built around the tube deck PCB The tube deck PCB has the tube sockets mounted on it as well as those critical circuit elements that need to be in close proximity to the tubes The tube sockets contain 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 tubes and in the other it switches the input RF to the tube matching circuit The tubes are operated as a swamped grid tetrode design The tube grids are 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 T
14. ally reset in about 4 seconds if the amplifier is returned to receive key up Never allow the red GRID LED to stay brightly illuminated for more than a second Frequent on off AC power cycling may shorten the tubes life It is less stressful to leave equipment in standby for several hours than to cycle power repeatedly on off on off over the same period 6 4 2 Interlocks The ALPHA 8100 is equipped with a cover interlock switch intended to remove primary power from the amplifier and a crowbar to short circuit the high voltage to chassis whenever the cover is lifted These interlocks are designed to protect against dangerous electric shock resulting from accidental contact with the lethal voltages inside the amplifier WARNING ALWAYS DISCONNECT THE AC LINE CORD FROM THE POWER SOURCE BEFORE REMOVING THE TOP COVER FROM THE 8100 FOR ANY REASON 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 not be disabled for any reason 6 4 3 Fuses Never replace any fuse with one of a different type or greater current rating Blowing of one ALPHA 8100 OPERATING MANUAL www alpharadioproducts com 44 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 USE ONLY 20 AMP 250
15. 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 8100 amplifier Warnings What Not to Do e Never open the amplifier case without unplugging the unit from the wall outlet e Never stick objects into holes in the case e Never touch an antenna during transmission e Never attempt to turn on the amplifier without the cover securely in place all attachment screws reinserted e Never turn the amplifier back on after a hard fault without waiting at least 20 seconds Always resist the temptation to immediately hit the ON button after the amplifier faults to power off e Never allow liquids to enter the amplifier through the cover holes 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 1 5 Owner Assistance Technical Assistance from Alpha Radio Products is available from several sources e The Alpha Radio Products web site is www alpharadioproducts com Click on Support and follow the instructions Many typical problems and their solutions are listed on this site On this site you can get the following assistance e Technical Support e Repair Information Software Downloads e Manuals e Tech Tips e Legacy Equipment Information ALPHA 8100 OPERATING
16. cover Carefully lift the transformer by the handle and move it into place at the rear of the amplifier taking care not to bump any of the boards and connectors on the power supply stack Locate the set of 4 screws and washers that are supplied with your amp and used to secure the transformer to the chassis Next slide and rotate the amplifier so that the right back corner hangs over the edge of the bench and insert the screw from the bottom of the amplifier and turn it into the nut on the transformer plate Continue this way rotating the amplifier on the bench until all of the screws have been inserted and turned Do not over tighten these screws as doing so may cause excessive vibrations or noise from the transformer Figure 4 1 shows an alternate method of transformer installation The extra piece of wood shipped with your amplifier is the transformer shim which was cut to specific dimensions to aid in this installation Once the transformer has been installed and all of the screws are in place holding it to the chassis you may proceed to attach the connectors as described in section 4 2 2 WARNING The transformer is very heavy and must be moved with due caution using only the lifting handle CAUTION PROCEED SLOWLY to avoid bumping and damaging adjacent wires connectors or components While the top cover is removed make sure each tube is firmly seated in its socket rubber exhaust chimneys are fully and correctly installed and anode co
17. d 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 ALPHA 8100 OPERATING MANUAL www alpharadioproducts com 33 6 Operation amp Maintenance The ALPHA 8100 is extremely easy to operate but failure to carry out each procedure exactly as described in this manual is likely to lead to amplifier damage which is not covered under warranty Damage to other station equipment may also result 6 1 Before Operating Your Alpha 8100 6 1 1 Setting Input Drive You must set the transceiver output power properly Virtually all damage to date has resulted directly from severe overdrive The ALPHA 8100 requires about 50 W drive for full rated output Damage caused by applying several times rated drive power to the ALPHA 8100 will not be covered under warranty Fortunately most modern transceivers maintain quite consistent output from band to band and mode to mode when set up properly CAUTION Setting only the transceiver POWER or RF PWR control IS NOT SUFFICIENT Several popular transceivers can generate RF spikes of 200 300 W Control of these spikes typically is done with a knob labeled DRIVE IC 781 FT 1000 or PROCESSOR OUT TS 940 TS 950 On SSB when speech processing is not used adjust the MIC or MIKE controls See the operator s manual for your particular
18. d moisture penetrate under the jacket Run the coax in straight lines as much as possible Support it frequently using non compressive clips so that it does not hang or stretch under its own weight Avoid sharp bends most manufacturers will specify a minimum bend radius for their product Make sure the connection from feed line to antenna is waterproof Provide for disconnection of the feed line when it is not in use this protects against damage caused by power surges and lightning strikes which are not covered under the amplifier warranty 3 6 RF Safety The FCC requires users to check their installations for compliance with published values for allowable exposure to RF fields This information is available in ARRL publications FCC printed rules and on the web Alpha Radio Products strongly recommends that this be done for any installation both fixed and at an expedition or contest site If you have any questions regarding engineering your 8100 into your amateur radio station please visit our online technical support website at www alpharadioproducts com ALPHA 8100 OPERATING MANUAL www alpharadioproducts com 16 ALPHA 8100 OPERATING MANUAL www alpharadioproducts com 17 4 Unpacking amp Preparation 4 1 Unpacking Remove the strap securing the two boxes to the pallet Inspect both boxes for physical damage Save all packing material and pallet for possible future use Contact 303 473 9232 if shipping damage is found Care
19. d reduces plate current to 30 50 mA during pauses in speech and key up intervals thus substantially reducing average power supply loading heat generation and wasted energy 6 4 6 RF and Mistuning Protection The ALPHA 8100 s exclusive circuit senses the beginning of any RF arc in for example a TUNE or LOAD variable capacitor and automatically switches the amplifier to standby within a few milliseconds This system has virtually eliminated RF arc damage in current ALPHA amplifiers The system similarly detects severe miss tuning of the 8100 and if drive exceeds about 25 W switches the amplifier to standby The 25 watt input trip threshold permits safe tune up at low power levels without aggravating and unnecessary trip outs ALPHA 8100 OPERATING MANUAL www alpharadioproducts com 45 6 5 Standard Maintenance Tasks 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 There are no user accessible lubrication points in the amplifier Do not apply oil or grease to any of the components The exterior ofthe ALPHA 8100 may be cleaned with a mild household liquid detergent Do not use chemical solvents as these may severely damage the front panel or cabin
20. e high power from the amplifier In addition inadequately rated coax or poorly assembled coax connectors may fail over time The cause should be investigated and corrected A good way to get more detailed information on antenna SWR is to use the Alpha Power 4510 or similar wattmeter 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 If the tube current exceeds about 2 5 amps the amplifier is shut off completely that is the AC is shut off The ON OFF switch will need to be used to put the amplifier back on line To avoid problems wait at least 20 seconds after this occurs before attempting to put the amplifier back on line If the amplifier trips again immediately investigate and cure the problem before attempting to turn the amplifier on again Repeatedly hitting the ON switch when the amplifier trips out is likely to result in severe damage to components in the amplifier If a hard fault trips the amplifier all the way OFF wait at least 20 seconds before turning the amplifier power on again If you are certain that you have taken care of the problem that caused the fault you may turn the amplifier back to operate and proceed with use 6 1 3 High SWR Considerations On any frequency where your antenna VSWR exceeds 1 5 1 it s important to carefully tune the ALPHA 8100 for a proper match The ALPHA 8100 does not contain an antenna tuner The SWR ca
21. ecting to external amplifiers 6 3 Initial Setup Tuning 6 3 1 Control functions The following chart shows the controls that allow you to adjust and monitor the amplifier RF OUTPUT kW 50 80 1 0 1 5 REFLECTED POWER W ALPHA 8100 HF LINEAR AMPLIFIER BAND MHz sTBY WAIT O O BAND Used to select amateur band desired in MHz 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 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 ALPHA 8100 OPERATING MANUAL www alpharadioproducts com 38 POWER Press ON to apply primary AC power to the amplifier or to reset power if the plate overcurrent relay has tripped Press OFF to remove primary AC power OPR STBY Operate OPR places the amplifier in line With the 8100 off in standby STBY or in warm up with the WAIT LED lighted the amplifier is bypassed and the exciter is connected directly to the antenna Metering LEDs Separate bargraphs provide instantaneous full time display of peak values amp Bargraphs RF OUTPUT Red and
22. ed with any appropriate transceiver e 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 1 3 Shipping Information The Alpha 8100 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 Ib 17 kg Both of these cartons are mounted on a wooden pallet and strapped down for a total weight of 98 lb 45 kg Alpha recommends that you retain the pallet and the cartons after installation in the unlikely situation that you need to ship the unit later Contact Alpha at 303 473 9232 for shipping advice and assistance 1 4 Safety Information Installation and Operation e Make sure the Alpha 8100 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 8100 weighs approximately 68 pounds when the transformer is installed Use proper lifting techniques and two people when moving the amplifier ALPHA 8100 OPERATING MANUAL www alpharadioproducts com e The Alpha 8100 is designed to meet international safety standards and FCC regulations However one should always remember that the equipment works with high voltages that can
23. et finish Never use an abrasive cleaner ALPHA 8100 OPERATING MANUAL www alpharadioproducts com 46 ALPHA 8100 OPERATING MANUAL www alpharadioproducts com 47 7 Troubleshooting Hints 7 1 Normal Troubleshooting 8100 will not turn on nothing happens when ON switch is pushed Correction 1 External AC wiring fuse or circuit breaker Check amp correct wiring replace fuse or reset may be open circuit breaker 2 Amplifier cover is not in place or properly Make sure cover is replaced and all screws secured cover safety interlock is open securely inserted 3 Fuse F1 F4 open or missing Check fuses Check and replace any blown fuses with fuses with an ohmmeter of the same size 4 Step start resistor open Check resistor If damaged replace Amplifier turns on but no HV is indicated by the multimeter LED bargraph Problem 1 Multimeter selector switch in wrong Set Multimeter switch to the correct position position e g Ip 2 Possible HV circuit fault 3 HV sampling resistor in power supply damaged 4 Transformer plugged into power supply Check power supply wiring and connectors to incorrectly be sure input and output connectors are set properly and the voltage taps have been set properly ALPHA 8100 OPERATING MANUAL www alpharadioproducts com 48 Amplifier turns on but no multimeter indication other LED bargraphs are operative 1 Low voltage power supply problem EA 2 De
24. fect or damage on control board O Amplifier turns on but time delay will not complete WAIT LED does not turn off Problem 1 Defect or damage in timing circuitry on Contact Alpha Customer Service control board Amplifier turns on time delay completes but amplifier will not transmit Problem 1 Open T R control line from transceiver to Contact Alpha Customer Service RELAY jack Amplifier transmits but red GRID LED illuminates often Problem 1 Amplifier overdriven or under loaded Reduce transceiver output and or increase amplifier loading 2 Load VSWR reflected power exceeds 200 W Check output cabling and antenna Correct impedance mismatches 3 Exciter output poorly controlled Consult exciter s User s Manual for assistance on controlling output 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 Problem 1 Input RF load resistor or bias circuitry Contact Alpha Customer Service damaged ALPHA 8100 OPERATING MANUAL www alpharadioproducts com 49 2 Possible damaged or defective tube s Contact Alpha Customer Service Receive signals disappear or are severely attenuated when switching from STBY to OPR 1 RELAY T R control cable from transceiver is Check T R control cable to make sure it is shorted switching properly Replace if needed 2 Transceiver locked i
25. fully unpack the amplifier and transformer Carefully remove the amplifier and place it on a workbench or table where you can install the power transformer This is a good time to remove the screws on the back panel which lock down the blower motor for transportation Retain these screws as they should be re installed if the amplifier is shipped again 4 2 Installing the Power Transformer 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 8100 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 to any degree the chassis of the amplifier can distort This may affect a number of things from the alignment of screw holes on the top cover to the band switch alignment and tension If the amplifier is moved even if only from one site to another locally remove the transformer to avoid the possibility of damage CAUTION Do not operate amplifier without the cover in place and all cover screws installed Do not operate the amplifier without a good RF ground connection on the rear panel ground terminal ALPHA 8100 OPERATING MANUAL www alpharadioproducts com 18 4 2 1 Install the Power Transformer Place the amplifier on the bench or desk where it is to be used and remove the cover screws and the
26. green GRID LEDs indicate respectively that normal peak drive has amp REFLECTED been reached and the onset of overdrive and flattopping A switch selected POWER bargraph monitors three additional functions TUNE Permits a simple and safe tune up procedure to be performed at low output power See section 6 3 2 Tune Up Plate current 1 5 amperes full scale approximately 75 mA per segment Plate voltage 3000 VDC full scale 150 V per segment 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 flattopping 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 Alpha Radio Products makes the ALPHA 2100 in line dummy load which simplifies this process Using the AP 2100 the operator can switch between the dummy load and the antenna at the flip of a switch 6 3 3 Grid Current Information The ALPHA 8100 operates in Class AB2 w
27. h ground such as a copper water pipe or driven rod via heavy copper braid or strap CAUTION When using any high power amplifier failure to connect ALL station equipment to a good common ground may allow RF feedback to leak into the transceiver and cause severe signal distortion 4 4 2 Replacing the Amplifier Cover Replace all attachment screws Use only the 6 32 screws supplied with the amplifier and do not tighten any of the screws until all are started Do not attempt to operate the amplifier with the cover removed or only placed back on the unit without the attachment screws This WILL cause damage to the Alpha 8100 and may also lead to injury or death to the operator 4 4 3 Blower Preparation The cooling fan is secured to the rear panel for shipping Be sure to remove the fan shipping hardware two 10 32 bolts fiber washers rubber shim from rear chassis wall Save this hardware It must be reinstalled whenever the chassis is transported 4 5 Amplifier Station Interconnections Once the power transformer is installed properly configured and the cover replaced place the amplifier in its operating position The amplifier with the transformer installed is heavy so you may need assistance to safely move it Make sure it is placed on a stable surface and that there is sufficient space to the rear sides and top to allow good air flow and safe placement of cables 4 5 1 Coaxial Cable Types amp Connectors Connect the transceiver R
28. he 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 At higher frequencies a relay shorts out some of this compensating inductance This relay is under microprocessor control and is actuated according to the band switch setting 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 minus12 volt and minus 124 volt supplies are also located on this board ALPHA 8100 OPERATING MANUAL www alpharadioproducts com 3 5 6 High Voltage Board The main high voltage for the amplifier is created on this board using a full wave bridge rectifie
29. hen 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 ALPHA 8100 OPERATING MANUAL www alpharadioproducts com 39 power output is reached readjust amplifier loading before continuing On SSB optimum output consistent with good linearity occurs when the green GRID LED 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 reduce drive and or increase amplifier loading The 8100 s 4CX800A GU74b tubes are 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 8100 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
30. ific For this reason the amplifier is not shipped with a power plug Select a location for the outlet as close as possible to where you expect to operate the 8100 If you are not sure or contemplate moving the amplifier you may choose to get a second outlet installed at the same time Ask your contractor for two or three matching plugs during installation as there are several styles of connector available Ask the contractor to measure the voltage and record it so you can set the line voltage tap on the 8100 appropriately If possible have the contractor measure the line voltage with a 10 amp current draw and use this value for setting the transformer tap The Alpha 8100 can run when connected to a 110V AC outlet However you WILL NOT achieve full legal limit output in this case If the amplifier is connected to a 110V AC outlet you should not expect more than 1000 W output 3 3 Air Flaw It is critical that airflow around the Alpha 8100 remain unimpeded at all times Keep the top of the amplifier clear of any restrictions If you are mounting the amplifier in a console make sure that the exhaust air is properly and fully removed from the console Poorly designed consoles can result in outlet air being drawn back into the amplifier air intake and recirculated thus getting ALPHA 8100 OPERATING MANUAL www alpharadioproducts com 14 Figure 3 3 Minimum clear ance for proper airflow To ensure adequate cooling make sure the top and
31. ifier 3 Key radio with 20W drive and adjust TUNE control for a peak in RF out which should be at the same point as a dip in Ip 4 Increase drive to get 1000W output going back and forth between the TUNE and LOAD to peak the RF output If more output is desired increase drive from radio slightly increase LOAD for a peak in RF out then peak RF out with TUNE control 5 When the amplifier is tuned correctly on 160m thru 40m the Ip should range between 0 9A and 1 1 A read on the 0 to 1 5A scale for 1500W output and input drive should not need to be more than about 60W On 20m the Ip will usually be about 1 0A for 1500W output 6 Plate current Ip is the most useful parameter to monitor on the multimeter bargraph during normal operation of the amplifier ALPHA 8100 OPERATING MANUAL www alpharadioproducts com 4D Alpha Radio Products alternate tune up procedure Nominal Gain Method Tuning up for Operation at 1 500 W RF Output Preset BAND GAIN and LOAD controls to the nominal positions given in your amp 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 1 Reduce transceiver carrier output control to ZERO 2 Press OPR operate on OPR STBY switch OPR LED should illuminate 3 Select the TUNE function of the multimeter bargraph 4 Switch transceiver to CW and increase its carrier output to approximately 15 W
32. ion 29 5 1 Theory of Operation Overview 29 5 2Tubes 29 5 3 Output Tank Circuit 30 5 4Tube Deck 30 5 5 Mains Board 30 5 6 High Voltage Board 31 5 7 Control Board 31 5 8 Display Board 31 5 9 Output Wattmeter Board 31 5 10 Center Partition Board 32 6 Operation amp Maintenance 33 6 1 Before Operating Your Alpha 8100 33 6 1 1 Setting Input Drive 33 6 1 2 Dealing with Faults 33 6 1 3 High SWR Considerations 35 6 1 4 Operating at Less Than 1 5 kW Requires Retuning 35 6 1 5 Lightning Protection 36 6 1 6 Operating in Bypass Mode 36 6 1 7 Never Use Transceiver Automatic AntennaTuner 36 6 2 Transceiver Connections 36 6 3 Initial Setup amp Tuning 37 6 3 1 Control Functions 37 6 3 2 Tune Up 38 6 3 3 Grid Current Information 38 6 3 4 ALC 39 6 3 5 Turning On The Amplifier 39 ALPHA 8100 OPERATING MANUAL www alpharadioproducts com 6 3 6 Tuning the Amplifier 40 6 4 Normal Use 43 6 4 1 Tubes 43 6 4 2 Interlocks 43 6 4 3 Fuses 43 6 4 4 Plate Overcurrent Relay 44 6 4 5 Idling Plate Current and Electronic Bias Control Ebs 44 6 4 6 RF and Mistuning Protection 44 6 5 Standard Maintenance Tasks 45 7 Troubleshooting Hints 47 7 1 Normal Troubleshooting 47 7 2 Troubleshooting Using the Serial Port 50 8 Glossary 55 ALPHA 8100 OPERATING MANUAL www alpharadioproducts com ALPHA 8100 OPERATING MANUAL www alpharadioproducts com 1 Introduction 1 1 General Description Congratulations on your purchase
33. ioned over the tubes When the warm up delay is complete about 150 seconds the WAIT LED will extinguish Put the OPR STBY switch to OPR and ALPHA 8100 is now ready 6 3 6 Tuning the amplifier po Bg o w o 3s as ss 60 A a w 65 6 Each ALPHA 8100 shipped from our factory will include an individual table showing the tune and load settings we used to achieve full output power on that amplifier into an AP 2100 a 50 ohm dummy load These settings usually vary slightly from those in the manual ALPHA 8100 OPERATING MANUAL www alpharadioproducts com 4 CAUTION Ifat any time in the following procedure the amplifier fails to respond as described remove drive immediately and turn the OPR STBY switch to STBY Verify all connections and cables turn the amplifier switch to OPR and proceed with the tuning procedure Alpha Radio Products recommmended 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 1 Please limit the transceiver drive to about 65W for tuning up and operating the amp 2 Set Multimeter to Ip Plate Current Set TUNE and LOAD controls to numbers indicated in the tuneup sheet originally included with the ampl
34. lacement for the GU74B The two tubes are operated in parallel and the Alpha 8100 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 Note that power output efficiency tube life and amplifier reliability may be compromised if tubes are used that do not meet Alpha s matching criteria Any damage sustained as a result of using unmatched tubes may not be covered under warranty The tubes are operated in Class AB1 with a plate voltage of 2 500V nominal full output key down a grid 1 voltage of 50 60 volts and a grid 2 voltage of 340 360 volts Each tube has a 15 ohm low inductance resistor in series with its cathode This resistor stabilizes the tube bias and provides negative feedback which improves linearity and hence IM 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 tubes resulting in less waste heat longer tube life and higher overall amplifier efficiency The artifacts of EBS are not noticeable under normal communications conditions ALPHA 8100 OPERATING MANUAL www alpharadioproducts com 30 5 3 Output Tank Circuit The output tank circuit of the Alpha 8100 is designed to provide reliable high efficiency low distortion performance in
35. ltage and current capacity may be estimated as Po max V xl 2 3 LINE LINE ALPHA 8100 OPERATING MANUAL www alpharadioproducts com oe 4 3 AC Primary Connections Primary voltage is selected by placing a jumper wire on the proper pin located on the mains board seated between the transformer and the front panel of the amplifier See Figures 4 2 and 4 3 figure 4 2 External Fan Interlock Blower Transformer AC Connector Tubes Vacuum Relay RF Choke Tank coil Crowbar Band switch Power Supply Mains Board Below are some considerations at the high end and the low end of this voltage range that are rarely encountered Low Voltage vs Power Output At the low end of the voltage range do not expect to be able to get 1 500 watts output if your line voltage is below 110 volts If your line voltage is between 110 and 130 volts then 1 500 watts PEP operation CW or SSB may be possible if your AC line service has sufficient current capacity 30 amp circuit recommended However 1 500 watts continuous should not be expected If your line voltage is between 90 110 volts then power outputs above 1 000 watts should not be expected from the amplifier Tune adjust the amplifier for no more than 1 000 watts output and simultaneously for maximum efficiency ALPHA 8100 OPERATING MANUAL www alpharadioproducts com E Low Voltage vs Current Draw If either of the two low voltage taps is used be aware that the amplifie
36. m Ie 2 4 Unpacking __ Unit Checked for Damage __ Transformer Installed Section 4 2 1 4 2 2 __ Power Cord Connector Attached Section 4 2 3 __ AC Primary Voltage Set Section 4 3 __ Amplifier Grounded Properly Section 4 4 1 __ Amplifier Cover Replaced and Secured Section 4 4 2 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 ALPHA 8100 OPERATING MANUAL www alpharadioproducts com 13 3 Station Engineering Considerations 3 1 Overview The Alpha 8100 is capable of dramatically improving the performance of your amateur station It is important that you observe good engineering practices to achieve all the benefits of such a station in a safe and reliable manner This section provides a few hints for important operational considerations but it is recommended that the user also consult a good source of general information such as The Radio Amateur s Handbook by the ARRL especially if this is the first high power amplifier you have used 3 2 AC Power Source This amplifier runs best when powered by a 200V 240V AC circuit If you do not have a 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 A 20 amp breaker on your 220V circuit is sufficient There are many styles of plugs some of which are country spec
37. n be tuned via the antenna or an external tuner connected to the output of the Alpha 8100 Nevertheless if the system SWR is below 2 1 the additional RF power loss of an antenna tuner can be avoided by tuning the 8100 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 6 1 4 Operating at Less Than 1 5 kW Requires Retuning If you tune the amplifier for maximum power output and then decide to operate the 8100 at a power output much different from 1 5 kW it must be re tuned for efficient and RF clean operation Under such lightly loaded conditions the green grid LED will probably be fully lit Note that if you tune the amplifier at 1 500 watts and then simply reduce power to 1 000 watts ALPHA 8100 OPERATING MANUAL www alpharadioproducts com 36 the tubes are actually going to run hotter than at 1 500 watts It is better to tune the amplifier with close to 50 watts of power but reduce the loading control to get 1 000 watts 6 1 5 Lightning Protection 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 however the only lightning proof solution available is to disconnect antenna feedlines and AC power when the equipment is not in use 6 1 6 Operating in Bypass Mode Whenever the 8100 is in line either off in sta
38. n transmit Make sure transceiver is properly switching between transmit and receive See transceiver s User s Manual for assistance Plate current indicated when amplifier is in STBY or receive Problem 1 4CX800A GU74b tube heater to cathode Contact Alpha Customer Support leakage or short 2 Tube bias supply or T R bias switch faulty Contact Alpha Customer Support Distorted SSB signal possible severe television interference 1 Excessive RF drive from transceiver and or Decrease drive from transceiver Re check insufficient amplifier loading amplifier tuning 2 Coaxial connector coax feedline antenna feedpoint balun tuner or antenna trap arcing on voice peaks 3 RF feedback from antenna into transceiver Make sure all power cords microphone via the transceiver power cord microphone or and key cables or other cables are properly key cable or other unshielded station patch shielded and grounded cables 4 Poor station RF ground Be sure the amplifier and transceiver have a proper RF ground Correct if necessary Low frequency 60 Hz audio hum on transmitted signal ALPHA 8100 OPERATING MANUAL www alpharadioproducts com 90 1 Defective microphone cord especially a Check to be sure microphone cord has not broken ground lead broken or does not have defective leads or connectors 2 Dynamic magnetic microphone located All dynamic microphones pick up some within about two feet of 810
39. ndby STBY or in warm up with the WAIT LED lighted the amplifier is bypassed and the exciter is connected directly to the antenna The throughput limit in all cases is 150 watts Any power level more than this may damage the RF switching relays in the 8100 6 1 7 Never Use Transceiver Automatic Antenna Tuner Never use an automatic antenna tuner into or through the 8100 This will cause damage to the Input wattmeter and Input T R Relay Note that many popular transceivers have built in antenna tuners that should be disengaged when driving your amplifier or transmitting through the amplifier with the amplifier in bypass mode 6 2 Transceiver Connections The following is a list of popular transceivers and considerations for their connection to the ALPHA 8100 amplifier Contact Alpha Radio Products Customer Service for advice on other transceivers Table 6 2 Typical Transceiver Connections Connection and Keying Information Icom RF T R Connection with the Send jack See the transceiver User s Manual for information ALPHA 8100 OPERATING MANUAL www alpharadioproducts com 37 Yeasu RF T R Connection with the RCA TX GND connector Also with the DIN Band Data connector See the transceiver User s Manual for information Kenwood RF T R See the transceiver User s Manual for information on connecting to external amplifiers Older Transceivers See the transceiver User s Manual for information on conn
40. nnectors are tightly clamped to each tube The silicone rubber chimneys installed on the 4CX800 tubes are a critical part of the cooling system Make sure the chimneys are straight and fully installed so the bottom of the chimney is firmly against the tube deck and completely covers the airflow openings in the deck Tube cooling exhaust 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 ALPHA 8100 OPERATING MANUAL www alpharadioproducts com 19 Figure 4 1 Transformer Installation 1 Ona flat surface with plenty of room carefully rotate the amplifier on to its right side power sup ply transformer side Rotate the transformer onto its right side placing the transformer squarely on the transformer shim the transformer should overhang the shim on all sides 2 Slowly move the amplifier and transformer togeth er making sure to align the nuts on the transformer with screw holes in the bottom of the amplifier 3 Once the transformer is settled into position and the screw holes are aligned secure the tranformer into place from the bottom of the amplifier Insert the supplied bolts 1 4 20 Y hex bolts with Y washers through the four clearance holes in the chas sis and into the nuts in the transformer base Once the transformer is secure
41. of a professional quality Alpha 8100 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 8100 is a self contained manual tune HF linear power amplifier capable of continuous operation at 1500 W peak power output on SSB keyed CW SSTV RTTY digital modes or FM with no time limit Other Alpha products available to enhance your use and enjoyment of the 8100 amplifier include Alpha 2100 full 1500 watt rated 50 ohm dummy loads and Alpha 4500 series SWR meters Wattmeter See our web site at www alpharadioproducts com or call 303 473 9232 for further information ALPHA 8100 OPERATING MANUAL www alpharadioproducts com 1 2 Amplifier Capabilities CAUTION It is extremely important to thoroughly review the Installation and Operation sections of this manual before attempting to use the Alpha 8100 Failure to do so could result in serious damage not covered under warranty e Continuous RF Output The 8100 is capable of 1 5 kW continuous RF output on all commonly used modes and on any authorized amateur frequency from 1 8 to 29 7 MHz e Compatibility with popular amateur transceivers and exciters The 8100 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 us
42. ower Cord Connections WARNING To avoid the hazard of a potentially fatal electric shock and or severe damage to the ALPHA 8100 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 ALWAYS use grounding type AC connectors which conform to local codes and ensure that the green wire in the Alpha 8100 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 The green conductor in the power cord is wired to the ALPHA 8100 chassis It MUST be connected only to the power source safety ground or neutral The black and white power cord wires connect to the two hot wires of the AC source either wire may be connected to either side of the line For best results use a dedicated 200 240 V branch circuit of 10 AWG copper wire or equivalent rated at 20 A to feed the amplifier 4 2 4 Important Information About Operation from 90 130U AC Electrical power equipment will draw twice as much primary current from 120 V mains as from 240 V mains Therefore operating the ALPHA 8100 on a typical 120 V 20 A household circuit without exceeding the 20 A circuit rating will limit maximum peak power output to about 600 1000 W Maximum possible RF output power for any particular primary AC vo
43. 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 standard 9 pin RS232 serial port is provided for remote monitoring and is found on the back of the Alpha 8100 A USB port is also provided Either port may be used but only one may be active at any one time The amplifier automatically senses when a PC is attached to the USB port and uses that port If nothing is connected to the USB the amplifier automatically switches back to the RS232 serial port 5 8 Display Board This board converts analog voltages into linear bar graph displays for the front panel It receives these voltages from the control board Various discrete LEDs are also on this board 5 9 Output Wattmeter Board This is a transformer coupled reflectometer with diode detectors The outputs from this board are DC voltages corresponding to the forward and reflected power sensed by the reflectometer ALPHA 8100 OPERATING MANUAL www alpharadioproducts com 32 These voltages are connected to the control board There is a trimmer capacitor on this board This capacitor is adjusted with the amplifier operating into a good 50 ohm dummy load The capacitor is rotated to minimize the reflected power voltage The board also has an 800V protection device on the RF output This is located between the PCB and the flange of the output connector 5 10 Center Partition Boar
44. pseudocode sum1 0 sum2 0 for n 0 to length payload 1 sum 1 sum1 Payload n sum2 sum2 sum1 next n The result is displayed as hexadecimal ascii Telemetry Sentence Send v to cause the unit to emit a sentence of this format SAPA01 01536 00002 0595 2654 0867 260 0519 008 3 4 00 0 8DA3 Start or flag character This can be used by an external program to locate the start of the sentence as it is never used elsewhere The checksum calculation begins after this character APAO1 Short for Alpha Power Amplifier type 01 This indicates the sentence is from an Alpha product an amplifier Type 01 sentences are frequently used for telemetry ALPHA 8100 OPERATING MANUAL www alpharadioproducts com E 01536 Output forward power in watts 00002 Output reflected power in watts 0595 Input RF power drive in tenths of a watt This shows 59 5 watts 2654 Plate voltage in volts 0867 Plate current in milliamps 260 Amplifier gain in tenths of a unit This shows a gain of 26 0 0519 1 times the voltage on grid 1 in tenths of a volt This shows that the grid voltage is 51 9 volts 008 Grid current in tenths of a milliamp This shows the grid current it 0 8 milliamp 3 Band switch setting 1 1 8 MHz 2 3 5 MHz 3 7 MHz 4 Amplifier mode 0 Off 1 warmup 2 On standby 3 On operate 4 keyed up 00 Fault code 0 Key sense End of the payload portion of the sentence The checksum calculation ends with the la
45. r 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 It consists of a string of Zener diodes and a series pass N channel MOSFET 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
46. r is normally shipped fused with 20A 250V fuses You may want to consider replacing these with 25A 250V slo blo fuses for very low line voltages less than 100 volts If you do be aware that the higher current at the lower voltage will significantly warm the power cord for the amplifier The cord as well as fuse holders and some internal connectors are operating near their maximum ratings due to the current demand at lower voltages Be sure that the AC cord is not coiled too tightly or placed where normal air flow is restricted because the cord could overheat If other equipment is drawing current from the same circuit as the Alpha 8100 then the considerations in section 4 2 3 should be taken into account High Voltage and Tube Life At the high end sometimes encountered when using poorly regulated generators the plate voltage and tube heater voltage may be too high If voltages above 250 volts are applied for any length of time the lifetime of the tubes may be reduced If this is your situation the first line of defense is to contact your utility 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 Another choice for voltage control a ferro resonant voltage regulator
47. rear of your amplifier have at least 3 of clearance to allow unobstructed airflow hotter and hotter and resulting in degraded amplifier performance or even failure If you are designing your own console consider putting in additional fans and or ducting to deal with waste heat Try to minimize the possibility of dust or other contamination getting drawn into or falling on the amplifier It is also advisable to periodically at least annually clean the dust out of your amplifier for continued flawless operation Alpha Radio Products recommends the use of compressed air for dust removal 3 4 Antennas Many antennas that are suitable for general use are unsuited for operation with a full 1500 W of power At this power level in a 50 ohm circuit the RMS current is 5 5 amps and the peak RF voltage is 387 volts With a 2 1 SWR these values double to 11 amps and 775 volts The actual voltage and current at various points in or on your antenna may actually be many times these values On a simple dipole with sharp wire ends corona localized ionization can easily occur Corona can and has led to fire in nearby objects Traps in beams and verticals can heat up significantly during high power operation Instances of melting or flashover of traps have occurred in many installations where insufficient thought has been given to their ratings If an antenna has been deployed for a long period of time it may be worth taking it down for inspection prior
48. st character preceding the 8DA3 Fletcher checksum FCS of the payload portion The FCS is a two byte quantity calculated over the payload portion of the sentence according to the following pseudocode sum1 0 sum2 0 for n 0 to length payload 1 sum 1 sum1 Payload n sum2 sum2 sum1 next n The result is displayed as hexadecimal ascii ALPHA 8100 OPERATING MANUAL www alpharadioproducts com 54 Send V to cause this sentence to be emitted continuously ALPHA 8100 OPERATING MANUAL www alpharadioproducts com 55 8 Glossary The following terms are used in this manual Detailed explanations may be found in various publications including the ARRL Handbook AB1 AC ALC ampere ARRL AWG CW dB EBS Exciter FCC FM FSK HF HV Hz Ip kV kVA Modulation class AB1 Provides good linearity in push pull configuration Alternating current Automatic Level Control Current measurement American Radio Relay League American wire gauge Continuous wave Decibel Electronic bias control The radio that provides RF drive for the 8100 to operate Federal Communications Commission Frequency modulation Frequency shift keying High frequency 3 to 30 MHz High voltage Hertz Idling plate current Kilovolts Kilovolts ampere kVA 0 8 kilowatts Kilowatt Light emitting diode Low voltage Milliampere Megahertz Operate Phase shift keying A digital modulation scheme Q
49. 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 prevent problems If there ALPHA 8100 OPERATING MANUAL www alpharadioproducts com 15 is any chance of people animals or objects 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 3 5 CoaH and Connectors The importance of a well constructed feed line system cannot be overstated After all the purpose of the amplifier is to provide approximately 2 S units 12 dB of improvement in your radiated signal All too often installation problems are encountered where cheap poor or under rated coax and connectors are used These often are responsible for at least one S unit of degradation This means you could have bought a 375 W amplifier and achieved the same radiated signal by buying good quality feed line components Use the lowest loss 50 ohm coaxial cable you can obtain Use new clean connectors installed according to the manufacturer s recommendation Clean the connectors after soldering them and before mating them with the amplifier Make sure any excess solder is removed from the connector likewise remove any fragments of braid etc Never use old coax which may have ha
50. uadrature shift keying In this CW transmitting mode the transmitter is only on for the duration of each dot or dash and switches to receive between each ALPHA 8100 OPERATING MANUAL www alpharadioproducts com 56 dot or dash allowing the operator to hear any signal being sent RCA RF RG x x RMS RTTY SSB SSTV STBY SWR T R UHF US VAC VDC VSWR Radio Corporation of America Also a type of interconnecting plug Radio frequency Coaxial cable type Root mean square Radioteletype Single sideband Slow scan television Standby Standing wave ratio A measure of antenna and feedline efficiency Transmit Receive Ultra high frequency 300 3 000 MHz United States Volts of alternating current Volts of direct current Voltage standing wave ratio ALPHA 8100 OPERATING MANUAL www alpharadioproducts com
51. you may carefully rotate the amplfier back to its standard orientation ALPHA 8100 OPERATING MANUAL www alpharadioproducts com 20 4 2 2 Connecting the Transformer Power Plugs 1 Connect the 9 pin white Molex connector to the matching plug mounted on the back wall of the amplifier 2 Connect the 8 pin orange connector to the matching pins on the upper Mains PCB 3 Connect the 6 pin yellow connector to the matching pins on the lower HV PCB 4 Check to be sure that all connector pins on these three connectors engage fully and correctly oe i Transformer to Low Transformer to High to Transformer Voltage Supply Voltage Supply HV Connector Molex Mains PCB PCB Found ake z 7 h Found Found towards towards the towards the the back of front of the front of the the amp amp transformer transformer transformer amp the top amp the lower side of the HV PCB rear of the Mains PCB ll First make fe CNet First make sure the A ew sure the connec connec tors are tors are properly y properly aligned ON aligned y AY First make sure the connec tors are properly aligned Gently but firmly press the connectors together till they are fully mated but firmly a but firmly press the wa press the connectors A connectors E together together till they are fully mated ALPHA 8100 OPERATING MANUAL www alpharadioproducts com e 4 2 3 P
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