B. Kainka

Radio Construction Mini Projects             

Burkhard Kainka 2023                 

Paperback: https://www.amazon.de/dp/B0CLRGZCV6

Ebook: https://www.amazon.de/dp/B0CLNGKPC7

Foreword 

For me, radio tinkering was the entry into electronics and the way to amateur radio. Against all prophecies of doom, that this is completely outdated and no longer relevant, the topic comes up again and again. Even now, when many medium wave transmitters are already switched off, when Deutsche Welle has said goodbye to short wave and when people are thinking about saying goodbye to good old FM broadcasting, the subject is still fun. Now more than ever, one would like to say, let's see what can still be received today. And there you can hear quite a lot, there are always signals to discover, which one did not know yet. Listen-ing to the radio is simply fun!

The tasks and projects are indeed diverse. Some radio hobbyists pursue the goal of rebuilding or optimizing historical detector receivers. Listen-ing to distant stations without a battery, just from the energy of the an-tenna, that has something. Or it is about putting old tubes back into ser-vice. There, too, a lot has happened since it became known that it even works with small voltages from 6 V. For a while, digital broadcasting DRM on short and medium wave was a big topic, leading many back to high frequency experiments. DRM is already on the retreat again, be-cause it has been shown that the transmission does not run as interfer-ence-free as one had hoped. But the many self-built receivers are still there and now serve other purposes from amateur radio to AM broadcast reception from distant countries.

With my penchant for radio tinkering, I am not alone, but hobbyists, but also many publishers and companies have taken up the topic, where I was often allowed to help. One highlight was the new Kosmos radio man with one tube and 12 V operation. Later, Franzis published a whole series of interesting vintage radio kits from medium wave to VHF, partly also for Conrad-Elektronik, where still a good number of these projects is available and facilitates the first steps. The topic of tubes is also sup-ported by AK Modul-Bus with several experimental systems, where basically only small, harmless anode voltages are used. But also special components and assemblies around radio tinkering, from the variable capacitor to the special IC or the complete DSP receiver and the match-ing class D amplifier. Whenever a new interesting component appears somewhere, which is not easy to get, I ask that it be added to the online store at Modul-Bus and thus become available to all interested radio hobbyists. The topic remains exciting!

This book tries to give an overview, from very simple experiments with material from the tinkering box to complex circuit board projects. I hope that you will be inspired by one or the other project.
Good luck and enjoy building your radio!

Burkhard Kainka
www.elektronik-labor.de

www.franzis.de
www.kosmos.de
www.ak-modul-bus.de
 

First published in German:
Radiobau-Miniprojekte


 CONTENTS

1 Medium wave crystal radio    1
2 Shortwave crystal radio    4
3 Transistor feedback    7
4 Tube feedback    9
5 The tube detector    11
6 Emitter follower feedback    14
7 TA7642 medium wave radio    17
8 The Franzis vintage radio    20
9 Regenerative shortwave radio    24
10 The wide-band PC radio    27
11 Emitter follower regenerative    30
12 Variable inductor tuning    32
13 The Franzis shortwave radio    35
14 Pentode regenerative    40
15 Regenerative for AM and DRM    43
16 The Kosmos Tube  Radio    47
17 Radios using battery tubes 2SH27L    53
18 2SH27L tetrode regenerative    56
19 Shortwave using the EF98    59
20 Tube headphone amplifier    62
21 EF95 shortwave regenerative    64
22 VHF super-regenerative receiver    68
23 The FM vintage radio    72
24 Stereo decoder    77
25 Deluxe vintage radio    85
26 Franzis FM plug-in module    88
27 CD2003GP AM/FM radio    92
28 Medium wave modulator    99
29 Tube AM modulator    101
30 Shortwave AM modulator    103
31 SI4735 DSP radio    105
32 The FM home radio    109
33 PC radio with USB connection    116
34 TPA3110D2 class D amplifier    118
35 BK1079/1068 FM radio    122