ozQRP MDT Construction Manual page 3

Figure 1 DSB generation ................................................................................................................................................ 6
Figure 2 Direct Conversion receiver ......................................................................................................................... 7
Figure 3 MDT Block diagram ....................................................................................................................................... 8
Figure 4 Carrier oscillator .......................................................................................................................................... 12
Figure 5 Mixer ................................................................................................................................................................. 13
Figure 6 Microphone Amplifier ............................................................................................................................... 14
Figure 7 Transmit .......................................................................................................................................................... 15
Figure 8 Receive Audio ................................................................................................................................................ 16
Figure 9 Diode identification .................................................................................................................................... 22
Figure 10 DIP ICs ........................................................................................................................................................... 23
Figure 11 Relay install ................................................................................................................................................. 23
Figure 12 Non-polarised capacitors ...................................................................................................................... 24
Figure 13 LPF capacitor marking ............................................................................................................................ 24
Figure 14 Trimcap install ........................................................................................................................................... 25
Figure 15 BD139 location .......................................................................................................................................... 25
Figure 16 BD139 lead identification ...................................................................................................................... 26
Figure 17 LED lead bending ...................................................................................................................................... 27
Figure 18 LED install .................................................................................................................................................... 27
Figure 19 Pot with tab removed .............................................................................................................................. 31
Figure 20 Component overlay .................................................................................................................................. 32
Figure 21 Mic connector wiring .............................................................................................................................. 33
Figure 22 Typical circuit voltages. .......................................................................................................................... 39
Figure 23 DSB transmit waveform ......................................................................................................................... 42
Date Issue
12-6-15 1
20-6-15 2
MDT Construction Manual - Issue 2
List of Figures
Change History
First release
Corrected values for R43 and C13, and other minor typos.
Comments
Page 3