The antenna is connected to a JFET RF amplifier Q1 followed by a 2 JFET regenerative stage (Q2,Q3). The low-level audio output is amplified by Q4 and a LM386 power amplifier drives the loudspeaker or a low impedance headset. This receiver relies on two power supplies : battery A is a 9 Volts one powering the RF sections while battery B is connected to the audio preamplifier and amplifier. According to the instruction manual, battery B could be any regulated DC power supply from 9 to 12 V. This 2 supply method keeps the voltage of the RF stages independent of any potential voltage fluctuations due to the audio amplifier current surges.
Soldering the components on the PCB is a simple work because the PCB is a large one.
The next work is to fit the front panel to the PCB and to attach 3 knobs found in my junk box to the potentiometers.
This is the receiver ready for tests.
This picture shows the front panel :
And here is the complete receiver in its oak enclosure.
2. Testing the receiver.
This little receiver performs well with a small antenna (6 m of wire going into the attic). Tuning is easy and I heard many broadcast stations on the 49 meters and on the 31-meter bands. Some ham stations were also heard on 40 meters and also on 20 meters when the band was open.
I connected the receiver input to my RF generator and found that a 9.8 MHz 2uV signal, 90% AM modulated by a 1 kHz signal, is perfectly audible in the loudspeaker. That's not so bad !
The currents drawn from the 2 power supplies are : 1.6 mA from Battery A and 6 to 70 mA from battery B, according to the audio volume.
Conclusion.
This simple receiver gives good results. It's easy to build and the adjustments are soon settled.
I only regret that 2 power sources are needed. In the near future I'll add a small 78L09 regulator in place of the battery A and compare the overall performances of the 1054 with and without this modification.
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