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Circuit 35: LM antenna amplifier for antennas with short wires
Setup information
Install the two transistors and the four resistors as shown in Fig. 2.35. Then install the three ceramic capaci-
tors. The six jumper wires come next. Check the placement on the board again and only then connect the
battery. Connect the circuit input to a short-wire antenna. The output is connected to the antenna input of
an LW – MW radio receiver – but only if you are familiar with the relevant safety guidelines on working with
devices that are to be connected to the mains as per VDE and know how to observe them
Experiment
If everything is wired correctly, the circuit will amplify the low receiving voltage of the wire antenna in LW
and MW ranges. You should be able to receive several remote stations during the day in addition to the
local station on medium wave. Despite or better due to the complex IP radio and DAB+ systems, the uncom-
plicated and genuinely mobile MW reception seems to be experiencing some sort of comeback.
The circuit diagram for this experiment is shown in Chap. 3, Fig. 3.35.
60
Components required:
1 x 2N3904 transistor,
1 x J111 FET transistor,
1 x 1 MΩ resistor,
1 x 56 kΩ resistor,
1 x 6.8 kΩ resistor,
1 x 470 Ω resistor,
2 x 100 nF ceramic capaci-
tors, 1 x 10 nF ceramic
capacitor, 1 x breadboard,
1 x 9V battery with clip
connector
Fig. 2.35: LM antenna amplifier
for antennas with short wires
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