DUAL GATE FET Amplifiers for all stages.


This is a universal FET amp, used in ALL amp stages:
Note the AGC voltage goes from 0 to 6 volt.

RF amp 14Mhz: with Gain Controll used for the -20dB / 0dB / +20dB front panel button
R1, R2 Not connected.
R4 is a green 3mm LED.
C1, C2 = 47pF NP0
T1, T2 = 2 turns 0.22mm cu, 20 turns 0.15mm cu, on 4mm adjustable form
See the first RF amp design

IF amp 10.7Mhz: with AGC (two of them is needed)
R1, R2 Not connected.
R4 is a green 3mm LED.
C1, C2 = 82pF NP0
T1, T2 = 2 turns 0.22mm cu, 20 turns 0.15mm cu, on 4mm adjustable form

BFO amp 10.7Mhz:
R1, R2 Not connected.
R4 = 560
R5 = 33K
R6 = 100K to +12V not AGC
R7 = Not connected.
C1, C2 = 82pF NP0
T1, T2 = 2 turns 0.22mm cu, 20 turns 0.15mm cu, on 4mm adjustable form

DDS amp 24Mhz:
R1 = 450 or 470
R2 = Not connected.
R4 = 51
R5, R6 = 10K to +12V not AGC
R7 = Not connected.
C1, C2 = Not connected
T1 = 5 turns Trifilar
T2 = 5 turns 4-filar
See DDS at bottom page for more info about this broadband amp.


This is the top side of the BFO Amp.


Bottom side og the BFO amp


This is the PCB layout, the Q1 is mounted on BOTTOM side
Only cobber on botton side is shown here, the whole top layer will also be GND cobber
Download Gerberfile


The FET is a BF960 or similar god old one, they are in SOT-103
Note the long pin is DRAIN, and the pin with a little extra shoulder is the SOURCE

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