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Summary of Contents for QRP PLUS

Page 1: ...SYNTHESIZER REFERENCE FREQUENCY 11 CIRCUIT DESCRIPTION 12 RECEIVE 12 SSB TRANSMIT 13 CW TRANSMIT 13 INDEX LABORATORIES HF Amateur Radio Transceiver the QRP PLUS Contents FEATURES 2 PUTTING THE QRP PLUS ON THE AIR 3 POWER 3 ANTENNA 4 5 PADDLE 5 MICROPHONE 5 EARPHONES 6 PANEL CONTROLS 6 OFF VOL 6 MAIN TUNING 6 DISPLAY 6 ATTENUATOR 6 FAST 7 MEM 7 PWR S METER 7 XCVE 7 REAR PANEL CONTROLS 8 SIDETONE LE...

Page 2: ... cell of 4 amp hour or greater capacity will also work well The QRP PLUS can be damaged by voltages greater than 15 Volts and will shut down if the supply voltage drops below 11 Volts Carefully observe the polarity when connecting the power source The center post is positive and the outer shield is negative The positive lead on the pigtail is identified with a red stripe Reverse connection will no...

Page 3: ... PLUS expects a 50 ohm matched load Excellent results can be obtained with a 60 foot or longer random wire if a suitable antenna tuner is used The tuner SWR bridge and antenna should be connected as shown in Fig 3 A good ground or counterpoise is important in the use of random wire antennas Many excellent books are available for more refined antenna designs Unlike most solid state transmitters the...

Page 4: ...revolution For rapid movement from one frequency to another the FAST button can be pressed while tuning The fast tuning rate is about 100KHZ per revolution MEM The QRP PLUS has 20 memories It comes from the factory with the memories preset to a few frequencies in each amateur band Any memory can be changed to any frequency desired Press the MEM button and tune to the memory you wish to change Tune...

Page 5: ...d CW modes The power can be varied smoothly from milliwatts to more than five watts The power for a given setting will remain approximately constant from band to band 8 SERVICE A one year warranty is provided with the QRP PLUS Terms are detailed on the warranty card provided with the unit Service is provided at the factory Please call the factory prior to returning a unit for service You pay shipp...

Page 6: ...h 1HZ resolution Signal Generator Adjust LO PCB Second board from bottom of stack See Figure 9 C47 and C48 trimmer capacitors 1 Tune the QRP PLUS to 7 300 0 MHZ 2 Connect the frequency counter to U4 MC145156 Pin 17 located near the trimmer capacitors 3 Slowly turn the main tuning dial The measured frequency should go from 4 000 312 HZ to 4 000 493 HZ then drop back to 4 000 312 HZ The QRP PLUS use...

Page 7: ...r of the passband This creates a 50MHZ carrier whose level is set by the CW power control From 12 13 output is buffered amplified and applied to the balanced mixer The synthesizer uses a Motorola 145156 IC and a dual modulus prescaler The reference frequency is 4MHZ The synthesizer uses 2KHZ steps Intermediate steps of approximately 10HZ are provided by controlling the reference frequency with a D...

Page 8: ... RP PLUS BLOCK O L OOMPPI O FIGURE 8 BLOCK DIAGRAM 15 ...

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