Wood amateur band receiver
This is a simple receiver for the 15 17 20 40 80 m bands.
10 points:
1 Single conversion superheterodyne with 10.245 MHz IF.
2 No variable capacitor. Only 3 varicap diodes. Note the 1N4007 diodes
in series with the zener to improve thermal regulation of the power
supply.
3 Wood baseboard (22 x 30 cm). Nails for connexion points (1 X 16 mm).
4 Plugin coils on DIN socket. At least 15 cm between the coils and the front panel in mandatory to avoid hand effect.
5 NPO capacitors for the oscillator.
6 Six pole QER crystal filter.
7 Two 47k potentiometers for the oscillator tuning: 10 turns for gross tuning, single turn for fine tuning.
8 1N4148 diodes to protect the mixer during transmission.
9 Class A is mandatory for the output stage (TIP122 with heat sink) to avoid frequency modulation of the oscillator.
10 Automatic volume control.
Plugin coils :
Antenna tuning : miniature coil
Band / Secondary / Primary
15 m et 17 m/ 1 µH / 1,1 µH (2x 2,2 µH in parallel)
20 m / 2,2 µH / 2,2 µH
40 m / 10 µH / 4,7 µH
80 m / 22 µH / 10 µH
Oscillator :
No coil form. Diameter : 22 mm
15 m / 10,755 MHz - 11,205 MHz / 3 turns / Ct = 481 pF / Cs = 220 pF / Cp = 220 pF
17 m / 7,823 MHz - 7,923 MHz / 4 turns / Ct = 780 pF / Cs = 156 pF / Cp = 220 pF
20 m / 3,755 MHz - 4,105 MHz / 8 turns / Ct = 570 pF / Cs = 680 pF / Cp = 220 pF
40 m / 3,245 MHz - 3,045 MHz / 10 turns / Ct = 680 pF / Cs = 470 pF / Cp = 220 pF
80 m / 6,745 MHz - 6,445 MHz / 5 turns / Ct = 827 pF / Cs = 330 pF / Cp = 200 pF
Olivier Ernst
F5LVG
2016
