New
high performance regenerative receiver 2013
Update 2019: a new and even better version is described here.
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
Olivier Ernst
F5LVG
01-2014