New high performance regenerative receiver

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Rx RX

I made this regenerative receiver for 5 amateur bands : 80 40 20 17 15m. With this Rx and a home made transmitter, I made several SSB QSO between North America and France. It is possible to listen, without noticeable detuning, SSB QSO on 15m during 15 minutes. There is no hand effect, no common hum and no mains hum.

I will focus on the following points:

1 RF attenuator, mandatory for all regenerative receiver.

2 Very small coupling capacitor between the antenna, the RF transistor and the tuned circuit to avoid overloading (I use my transmitting antenna).

3 Plug-in coils without coil forms to obtain very high Q. The coils are easy to make : only one coil without tap for each band. I use 4 pins DIN connectors.

4 High C “oscillator” with NP0 capacitors to obtain a high frequency stability.

5 Band spreading with small capacitors in series with the variable capacitor.

6 High capacitor value between the tuned circuit and the detector to avoid mains hum.

7 Very short connection for the dot and dash lines.

8 Fine tuning with a 1N4007 diode.

9 1N4148 : transistor protection during transmission.

Diameter for the coils : 22mm

80m, L=11 turns, Ct=470pF, Cp=122pF

40m, L=5 turns, Ct=552pF, Cp=55pF

20m, L=3 turns, Ct=320pF, Cp=25pF

17m, L=2 turns, Ct=440pF, Cp=16pF

15m, L=2 turns, Ct=253pF, Cp=16pF

Wire for 80 40m : diameter 0.5mm.

Wire for 20 17 and 15m : 2.5mm2 installation cable.

Good DX, 73

Schematics

Olivier Ernst

F5LVG

01-2014