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1. any 50 ohm cable RG S8 is fine with PL 259 plugs Connect the existing station antenna system to the RF OUT connector on the AL 811 with any 50 ohm coaxial cable capable of carrying 500 watts Use shielded audio type cable with standard male phono plugs to connect the RELAY jack on the AL 811 to the exciter s normally open amplifier keying circuit The keying circuit in the AL 811 has positive 12 VDC open circuit and provides 100mA of current when pulled to ground The AL 811 has an internal back pulse canceling diode across the relay coil Connect the shortest ground lead possible from a good earth ground to the GND terminal The best leads are solid instead of stranded or braided copper It is also best to use a common ground point for all the equipment in the station Use a shielded audio cable with a standard male phono plug to connect the ALC jack to the negative going ALC input jack on the exciter Do not connect this line until you have read and understand the function of the ALC circuit Exciters with output powers below 70 watts do not normally require this connection If this hack is connected without adjusting the ALC control the exciter may not develop any drive power CW PROCEDURE Follow the instruction in numerical order If the various meter readings are different than the instructions check the connections from the exciter to the amplifier and make sure they are correct Consult the manual for the exciter if necess2. on the plate choke and air variable capacitors attract dust and dirt out of the air stream It is particularly important that the high voltage areas at the bottom of the of the plate choke and the insulator on the air variable capacitors be dust free These areas should be inspected every few months if the amplifier is operated in a dusty environment Unplug the line cord and wait at least 90 seconds until the power supply capacitors discharge Remove the cover and connect a jumper wire from ground to the anode connection of the tubes NOTE This is a safety wire that must be installed when beginning service work and removed when work is finished Use a soft bristle brush dipped in alcohol to clean areas mentioned previously Amplifier Tuning Chart Log BAND LOAD PLATE 160 CW 160 SSB 80 CW 75 SSB 40 CW 40 SSB 30 CW 20 CW 20 SSB 17 CW 17 SSB 15 CW 15 SSB Fill in this chart with you actual settings and you can quickly change bands We suggest you use a pencil as settings may change as you alter your antennas AL 811 SCHEMATIC Power supply shown wired for 120V operation 4 E TT toe nar ee f Jo Rs oF Nodes W1 W2 W3 W4 W5 W6 W7 W8 and W11 correspond to the nodes on the 50 0453 1 Schematic AL 811 INPUT CHART ET 160 28 75T 405 1287 1300 250 1130E 80 23 75T 405 1237 500 250 0500 40 750 250 0750 13 75
3. twist the tube s excessively Also check that the anode caps are secure and did not come loose during the unwrapping process The white ceramic anode connectors will have to be removed from the top metal cap of each tube if it ever becomes necessary to remove the tubes from the amplifier This can be a difficult procedure because of the high clamping force of the internal springs in the anode connector may hold it to the cap very tightly The tube will break if direct upward or rocking pressure is applied in an attempt to remove the connector The safest way to remove the ceramic connector is to lift the tube out of its socket A twisting or spinning pulling motion can then be applied while holding the ceramic connector firmly until the tube and connector are separated Repeat the procedure for the other tubes Install the cover with the vent holes to the left near the tubes by installing the back screws first Install all the screws loosely and tighten them only after all the screws are in place Install the fuses and fuse caps on the back of the unit Read the manual to become familiar with the operation of the AL 811 amplifier AL 811 LINEAR AMPLIFIER FEATURES The AL 811 is a grounded grid linear amplifier developed by Ameritron using low cost 811A power triodes It operates in class AB2 for SSB and CW 1 Fast Warm Up Time The 811A tubes take approximately 3 seconds to warm up 2 Long Tube Life The 811A tubes are long lif
4. Hz or 60 Hz The Transformer Connections chart at the bottom of this page shows proper connections for various line voltages The AL 811X export model is wired for 240V 50 60 Hz operation The appropriate plug is not provided for this model You must wire the proper plug on the end of the power cord supplied Simply cut the existing plug off and wire the appropriate plug in its place If the line voltage in your country is not 240V then you must change the transformer to the appropriate setting indicated by the chart below Note the AL 811 transformer allows operation on 100V line voltage in countries such as Japan NEVER REWIRE THE POWER SUPPLY TO BOOST THE HIGH VOLTAGE ABOVE 1800 VOLTS The wiring between the fuse box and the amplifier AC outlet must be 14 gauge or larger in order to supply the operating current required 8 amperes without a significant drop in the line voltage The outlet should be fused for the wire gauge used Factory wired operation for the AL 811 Factory wired operation for the AL 811X VOLTAGE BUCK BOOST PRIMARY 120 Atol Bto2 CtoD EtoF 110 1 to 2 A B open Cto D EtoF 100 A to2 B to I C to D E to F For 240 230 220 all three primary conditions apply s Atol Bto2 no connection C to D 1 to 2 A B open DtoE Ato2 Btol no connection E to F INTERCONNECTIONS Connect the RF output of the transmitter to the RF IN connector on the rear of the AL 811 with 50 ohm coax Use
5. LC circuit converts a portion of the RF drive voltage at the exciter end of the tuned input circuit to a negative going control voltage This voltage should be used to limit the exciter drive to safe drive levels for the AL 811 for exciters that develop more than 70 watts of output power A capacitive divider consisting of C27 and C28 is used to reduce the RF voltage and drive a rectifier circuit consisting of D17 and D18 The resulting voltage is filtered by C29 and R12 and applied to the ALC potentiometer R14 R13 provides RF and DC isolation for the ALC jack The DC isolation prevents loading of the exciter ALC input line by the ALC potentiometer The ALC circuit can be adjusted by loading the AL 811 slightly beyond the recommended maximum values with the ALC line disconnected The ALC line can then be connected and the ALC control on the amplifier adjusted to a point just before the drive begins to decrease The primary use of the ALC function is the prevention sive drive levels This circuit will not prevent small changes in output power from occurring on different bands Destructive levels of drive power are those above 100 watts under most conditions Slight changes may occur in maximum output power on different frequencies with the ALC connected A compromise in ALC adjustment may be necessary to achieve acceptable performance on all bands PLATE SUPPLY The power supply in this amplifier uses a combination plate filament and con
6. PLEASE READ THIS MANUAL BEFORE ATTEMPTING TO OPERATE EQUIPMENT UNPACKING INSTRUCTIONS Carefully lift the amplifier by the bottom cabinet edge out of the shipping carton Place the amplifier on a firm level surface and carefully inspect it for shipping damage Contact the shipper immediately if any damage exists Do not discard the carton or packing material Remove the twelve screws holding the cover on with a number 2 phillips screwdriver Carefully lift the cover off the amplifier Save the screws to resecure the cover Locate the fuse pack with the two 12 amp fuses and fuse caps If additional screws are needed they will be in the fuse pack also NOTE Fuses supplied are for 120 110 100V operation If you are rewiring the AL 811 for 240 230 220V operation you must use 8 amp fuses The AL 811X export model is pre wired for 240V operation and is supplied with 8 amp fuses Remove the foam packing material left side front view that secures the 811A tubes during transit Carefully unwrap the tubes Do not dislodge the Aluminum shaft that is connected to the rear input bandswitch wafer To install the tubes in the sockets be sure the large diameter pins line up with the two large diameter holes in each socket Do NOT rock or twist the tubes excessively during the installation If the tubes are already installed check the tubes for proper seating If necessary press the tubes down into their sockets with gentle force Do not rock or
7. T 405 1137 500 250 0500 330 250 0330 9 75T 405 1097 180 250 0180 270 250 0270 6 75T 405 1067 150 250 0150 180 250 0180 4 75T 405 1047 100 250 0100 50 0453 1 SCHEMATIC 50 0453 1 PARTS LIST 18pF DM15 250 0018 0 01uF 100V Disc 200 2100 1 100uF 25V Elect 270 6100 1 1N4007 300 4007 1N4148 300 4148 39 Ohm 1 4 Watt Resistor 100 1390 10 Ohm 1 4 Watt Resistor 100 1100 DPDT Relay 408 6124 SPDT Relay 408 6114 2N3904 TRANS 305 3904 MJF3055 TRANS 305 3055J PARTS LIST Ameritron Part Bl Fan Cl 2 21 22 0 01 uF 250V Disc 410 3583 T3 4 See Input Chart C5 7 19 30 31 0 01 uF 50V Disc 200 2100 1B C12 0 01 uF 100V Disc C5 6 2200 uF 25V Elec C8 9 10 11 29 0 01 uF 1kV Disc 200 2100 270 7220 1 200 2100 2B C27 27 pF 500V DM10 250 0027 C13 0 001 uF 7 5kV Disc 200 1 100 7 C14 Air Variable 282 2572 1 C15 16 17 18 210 uF 470V C20 0 1 uF 25 50V Disc 270 6210 7 200 3100 C23 68 pF 500V Disc 250 0068 C24 500 pF 1000V DM15 C25 360 pF 1000V DM19 252 0500E 252 0360E C26 Air Variable 282 2113 150 pF 500V DM15 250 0150 1N4007 300 4007 MV6753 Red LED 351 5002 1N5408 300 5408 1N270 302 0270 1N5408 300 5408 50 239 610 2005T S
8. ary Be sure the transformer is correctly wired for your line voltage See the POWER CONNECTIONS instructions on page 4 for wiring details 1 Set the AL 811 front panel switches as follows OFF ON to OFF OPR STBY to STBY Ip HV to HV 2 Plug the line cord into the proper voltage outlet 3 Set the power switch to the ON position the meter lamps should light and the fan should start Read the 2000 volt scale on the multimeter It should indicate 1700 volts nominal and no more than 1800 volts 4 With the amplifier still on STBY tune the exciter into the normal 50 ohm load according to the manufacturer s instructions Turn the exciter drive fully down after tuning 5 Place the amplifier bandswitch on the same band as the exciter the PLATE control in the dial range for the band selected and the LOAD control as indicated MHz Plate Load MHz Plate Load 1 80 1 3 10 0 7 0 1 90 2 4 14 0 81 2 41 2 3 5 41 2 3 18 1 8 1 2 4 3 7 5 4 21 0 9 5 4 0 51 2 41 2 24 5 4 81 2 7 0 71 2 41 2 28 5 91 2 5 73 71 2 41 2 TUNE UP 6 With the exciter drive still at zero place the HV Ip switch in the Ip position Observe the 750mA scale It should read zero Place the STBY OPR switch in the OPR position 7 Key the exciter no drive The Transmit XMT LED should light Observe the plate current on the 750mA scale It should be 110mA NOTE The no drive current will vary up to 25 due to component and line voltage tolerances 8 Appl
9. e reliable transmitting tubes 811A tubes offer rugged reliable operation even on RTTY and SSTV 3 Tuned Input A Pi Network tuned input matches the 811A tubes to 50 ohm exciters 4 Two Illuminated Panel Meters The AL 811 has two illuminated panel meters The Grid Current meter provides a continuous reading of the 811A grid current to indicate proper loading of the amplifier The other meter switches between high Voltage HV and Plate Current Ip 5 Safety Interlock Removes AC from the unit when the cover is removed Never attempt to defeat this switch 6 Operate Standby Switch Used to remove the amplifier from the RF line while filament and plate voltages are maintained for barefoot operation 7 XMT Indicator LED Provides a front panel indication of proper amplifier keying by the exciter during operation 8 ALC Voltage The drive level is detected to provide a negative control voltage for the exciter ALC prevents overdriving of the linear and reduces distortion from excessive drive power CAUTION This amplifier must be disconnected from the power mains before removing the cover See the precaution on page 7 TECHNICAL SPECIFICATION AL 811 Frequency Coverage Domestic model AL 811 160 80 40 30 20 17 and 15 meter bands Export model AL 811X 160 80 40 30 20 17 12 and 10 meter bands Input Circuit type Pi Network slug tuned coils Maximum VSWR at resonance 1 3 1 Minimum 2 1 VSWR bandwid
10. heck the high voltage potential WARNING never remove the cover of this amplifier with the unit plugged into the power line DRIVING POWER This amplifier is designed to operate at full ratings when it is driven by an that has aproximately 70 watts of RF output You can use an exciter that has lower output power but the amplifier s output may be less If you use an exciter that delivers more than 70 watts carefully adjust the driving power to avoid over drive and the creation of spurious signals which create needless interference to other operators We highly recommend that you use a monitor scope for continuous output monitoring The display on an oscilloscope is the best readily available way of determining the amplitude of the voice peaks which if excessive can cause flat topping and splatter IMPORTANT In no case should you advance the power output control of your exciter beyond the point where the amplifier s power output indication ceases to increase Nonlinear operation may occur if you turn the control past this point FILAMENT SUPPLY The filament circuit of this amplifier satisfies all requirements of the tube manufacturer related to tube performance and life Inrush current is controlled by the transformer internal resistance and impedance filament choke resistance and filament wiring resistance To insure maximum life of the tube never replace any circuit components or wiring with substitute parts ALC CIRCUIT The A
11. il please allow at least three weeks for a written reply AMERITRON 116 Willow Road Starkville MS 39759 Telephone 662 323 8211 FAX 662 323 6551 METERING FUNCTIONS The AL 811 has two illuminated panel meters The right meter reads PA grid current up to 200mA The normal current with a single tone carrier signal will be around 150mA If the current is too high during full power operation the loading control should be advanced to a higher setting If the current is too low the loading control should be turned to a lower setting The left meter reads PA high voltage of 2000 volts and plate current of 750mA The normal readings are 1500 1700 volts HV and 550mA of current at full rated output with a single tone signal INSTALLATION LOCATION Do not operate the amplifier in excessively warm locations or near heating vents or radiators Be sure air can circulate freely around and through the amplifier cabinet Provide an unobstructed air inlet for the blower Do NOT place any books magazines or equipment that will impede the free flow of air near the sides of the cabinet VENTILATION The AL 811 ventilation system has been designed and tested to maintain the 811A tube temperature safely below the tube manufacturer s rating at 400 watts output with a 100 duty cycle To insure proper ventilation in you installation observe the following 1 Do not block or restrict the ventilation holes in the cover 2 The exhaus
12. ingle Phone Jack See Input Chart 600 1003 Choke Filament 10 15115 1 2 5mH Choke 401 6250 1 5 1 2 inch Plate Choke 10 15197 16 Air Coil HF Coil 404 0811 10 13140 Plate V Meter 400 2601A Grid Current Meter 400 2600A 4 7k Ohm 1 2 Watt 50k Ohm 7 Watt Type 170S T Meg Ohm 3 Watt 101 3470 107 4500 104 6100 1 5 Ohm 3 Watt Type 135 104 0150 0 6 Ohm 3 Watt Type 135 104 0060 330 Ohm 1 4 Watt 100 2330 180 Ohm 1 4 Watt 100 2180 3 3k Ohm 1 4 Watt 100 3330 10k Ohm 1 2 Watt 101 4100 100k Ohm Potentiometer 162 5100 1 Wafer Switch Band Switch 500 4811 500 2811 Rocker Switch w Light 507 1151 SPST Switch 507 1147 Safety Interlock Switch 504 3247 Power Transformer 406 1532 811A Tube 380 08 11A 12 Amp 120 Vac Operation 8 Amp 240 Vac Operation 755 1114 1 755 0108 Parasitic PCB 3 pc 100 Ohm 3 Watt 6 pe 100pF DM15 3 CAP 811 50 0811 1 104 2100 250 0100 755 6811
13. on SSTV FM RTTY PACKET AMTOR The plate current should be limited to 400mA maximum The grid current should be limited to 120mA and the amplifier tuned for peak output power with the drive reduced to hold the grid and plate currents below the ratings given NOTE Some exciters put out short duration high power RF pulses when first keyed Exciter power output peaks may reach or exceed full output level settings even if the exciter s power control is adjusted to deliver a fraction of full power under keydown conditions The amplifier loading control must be set high enough clockwise to prevent extremely high energy levels from developing in the plate and grid circuits of the amplifier DO NOT UNDERLOAD THE AMPLIFIER TO REDUCE POWER Never retune the amplifier to produce higher efficiency with reduced drive except under the SSTV FM RTTY PACKET and AMTOR section Poor linearity splatter or even damage to components may result from failure to follow instructions QSK OPERATION The open frame relay in the AL 811 takes approximately 15ms to switch states This precludes using the standard internal relay for QSK CW operation Commonly available vacuum relays are very marginal for high speed QSK operation At 60 WPM less than 50 of the available deceive time can be used due to the slow speed of vacuum relays On PACKET AMTOR and other modes delay can be added to the transmit and receive changeover to use either vacuum or our s
14. t air flow is over 20 CFM Do not assist the air flow unless the fan exceeds the AL 811 fan CFM by a factor of 2 1 3 Do not mount additional fans on the AL 811 cabinet 4 The exhaust air will become warm at high power levels Do not place any heat sensitive objects in the exhaust air stream GROUNDING Connect a good earth or water pipe ground to the ground post on the rear panel of the amplifier Use the heaviest and shortest connection possible Before you use a water pipe ground inspect the connections around the water meter and make sure that no plastic or rubber hose connections are used These connections interrupt electrical continuity to the water supply line Install a jumper around any insulating water connections you may find Use heavy copper wire and pipe clamps It is best to ground all equipment to one point at the operating position and then ground this point as described above POWER CONNECTIONS The AL 811 is supplied with a NEMA 5 15P plug for 120V operation The power required to operate the AL 811 is not high enough to warrant 240V operation unless 120V is not available The fuses should be 12 ampere fuses for 120V and must be changed to 8 amperes for 240V operation The diagram to the right shows the proper wiring for 120V operation Operation on a voltage of 240V is not required nor will it necessarily improve performance The power transformer will perform equally well with a power line frequency of 50
15. tandard conventional relay effectively Ameritron offers a high speed switching option for operators that require high speed switching between receive and transmit The system switches in one mS Therefore these systems are several times faster than available vacuum tube relay systems and allow over 90 of the available receive time to be used at 60 WPM The QSK 5 stand alone PIN diode switch can be used with almost all types of amplifiers and transmitters No modification are required to the amplifier with the QSK S Contact Ameritron for details on the QSK 5 The AL 811 will operate with full output on all WARC bands except 24 5 MHz The AL 811X will operate with full output on all WARC bands STANDARD FREQUENCY CONVERAGE AL 811 1 8 2 0 MHz 3 5 4 0 MHz 7 7 3 MHz 10 1 10 15 MHz 14 0 14 35 MHz 18 1 18 2 MHz 21 0 21 45 MHz 160 meters 80 meters 40 meters 30 meters 20 meters 17 meters 15 meters AL 811X 1 8 2 0 MHz 3 5 4 0 MHz 7 7 3 MHz 10 1 10 15 MHz 14 0 14 35 MHz 18 1 21 45 MHz 24 9 29 7 MHz 160 meters 80 meters 40 meters 30 meters 20 meters 17 15 meters 12 10 meters WARNING DO NOT ATTEMPT TO PUT THIS AMPLIFIER IN SERVICE WITH THE COVER REMOVED CONTACT WITH VOLTAGES INSIDE THIS AMPLIFIER CAN BE FATAL ALWAYS DISCONNECT THE AMPLIFIER FROM THE POWER MAINS AND WAIT FOR THE FILTER CAPACITORS TO DISCHARGE BEFORE REMOVING THE COVER PERIODIC MAINTENANCE The high voltage present
16. th 15 Maximum drive power permissible 100 watts Typical drive for rated output 75 watts Output Circuit type Pi Network 1 2 hour carrier 400 watts 30 second carrier 550 watts 1 2 hour PEP two tone 600 watts 30 seconds PEP two tone 600 watts Efficiency typically 65 Power Supply Circuit type full wave bridge Full load current 550mA Regulation 12 Maximum draw at rated output 8A Metering Multimeter reads HV and plate current Grid meter reads PA grid current Connectors Relay keys amplifier when grounded Sources 12 VDC open circuit and supplies 100mA when grounded A built in pulse canceling diode protects the exciter RF input SO 239 50 ohm input RF output SO 239 50 ohms needed with full power will load into any SWR below 3 1 at reduced power output Power NEMA 15 15P 120V grounded style Physical Dimensions 16 D x 13 4 W x 8 Weight 30 lbs specifications are subject to change without notice or obligation GENERAL INFORMATION SAFETY INTERLOCK The interlock switch closes to allow AC line voltage to reach the power transformer as long as the AL 811 s top cover is in place When the top cover is removed the interlock opens and disconnects the line voltage This does not discharge the bank of power supply filter capacitors Be sure to allow the filter capacitors to discharge before you touch anything inside the amplifier You can select the High Voltage function of the Multimeter to c
17. trol transformer A buck boost winding is provided to allow the user to compensate for low medium or high power line voltage This amplifier is normally supplied wired for the highest power line voltage setting Never change this setting unless you are positive that performance is suffering due to low filament and plate voltages The life of components will be shortened drastically if the high voltage exceeds 1800 volts at rest The diagram on page 4 shows proper wiring for each voltage EXPORT MODIFICATIONS A simple modification will allow operation on frequencies above 15 meters Instructions for this modification are available by sending a written request for Export Modification Instructions along with a copy of a valid amateur license There is no charge for this information Export models are shipped with this modification and have an X following the serial number Standard frequency coverages are indicated in the chart on page hs TECHNICAL ASSISTANCE Technical assistance is available during our normal business hours on weekdays The following information is required to assist you with operational problems e Model and Serial Number e Date of purchase and dealer e An accurate description of the problem Meter readings at all stages of the tuning procedure are very important along with a complete description of the other equipment used with our product Written assistance is also available Due to time delays in processing ma
18. y only enough drive to indicate a grid current of 100mA OR an Ip of no more than 450mA Tune the PLATE control for maximum output power It is normal for the plate current to dip at this point If the grid current goes over 150mA reduce the drive at once Unkey the exciter 9 Observe the output on an external RF wattmeter Increase the drive until full exciter power never to exceed 100 watts or 200mA of grid current is achieved Quickly adjust the PLATE and LOAD controls for maximum output power 10 Reduce the drive until the desired output levels are obtained NOTE Rotating the LOAD control clockwise reduces grid current for a given amount of drive If the LOAD control is set at too low a numerical setting a severs stress on tank components may occur The PLATE control should always be peaked for maximum grid current or output power Do not exceed 700mA of plate current during tune up OPERATION OF OTHER MODES SSB Tune up the exciter and amplifier as described in TUNE UP section and switch the exciter to SSB Normal ranges of meter readings on SSB are between 20 and 50 percent of the CW carrier readings This is due to the different peak to average power ratios in the operators speech waveform The only true way to measure peak output power is with a good peak reading wattmeter or monitor scope A whistle should produce the same values obtained on CW Any effort to run more than these values will produce splatter and distorti
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