Conrad UKW Manuale utente
Imprint
© 2011 Franzis Verlag GmbH, 85586 Poing
www.franzis.de
Author: Burkhard Kainka
Art & Design, Composition: www.ideehoch2.de
ISBN 978-3-645-10057-1
Produced on the order of Conrad Electronic SE, Klaus-Conrad-Straße 1, D92240 Hirschau
All rights reserved, including the rights of photo-mechanical reproduction and storage in electronic media.
Generation and distribution of copies on paper, data carriers or online, in particular as PDF, is only permissi-
ble with the express consent of the publisher; violation of this will be prosecuted.
Most product designations of hard- and software and company logos named in this booklet are usually also
registered trademarks and should be observed as such. The publisher essentially uses the manufacturer’s
spellings for the product designations.
All circuits and programmes introduced in this book were developed, tried and tested with the greatest possi-
ble care. Nevertheless, mistakes in the book and software cannot be fully excluded. The publisher and author
do not assume any liability for incorrect information and their consequences.
Electric and electronic devices must not be disposed of in the domestic waste! At the end of its service life, dis-
pose of the product according to the relevant statutory regulations. Collection points for returning electronic
devices free of charge have been established. Your municipality will inform you of where such collection
points are located.
This product complies with the relevant CE directives if used according to the included instructions. The descrip-
tion belongs with the product and must be passed on with it.
2
UKW Retro Radio
The UKW Retro Radio 4
Components 5
Installation of Control Elements 6
Soldering 8
First Test and Settings 12
Reception Practice 13
Explanations on the Circuit Diagram 13
3
4
The UKW Retro Radio
This state-of-the-art VHF radio with traditional design receives FM stations in the
range of 87.5 MHz to 108 MHz with good reception performance. You will mainly
hear the strong local stations with good sound. However, the receiver is sensitive
enough to also receive remote stations at times.
VHF radio was not widely introduced before 1945. Initially, there were still many
radios that were only able to receive the AM ranges long wave, medium wave
and short wave. Many devices could be retrofit to receive VHF. The tube superhet
with VHF range became generally popular in the 1950s.
This radio looks reminiscent of a typical portable radio from the 1960s. With in-
vention of the transistor, radios could be built that could be operated at lower
energy than tube receivers. They could therefore also be battery-operated. Apart
from this, they remained technically similar to older tube radios.
D1 varactor diode 1SV101
R1 4.7 kO(yellow, violet, red)
R2 220 kO(red, red, yellow)
R3 1 kO(brown, black, red)
R5 330 kO(orange, orange, yellow)
R6 33 O(orange, orange, black)
C15 Elko 100 µF
C17 100 nF ceramic (104)
5
With the highly integrated receiver IC TDA7088, construction of a dedicated VHF
radio has become so simple that anyone is able to successfully solder together
this radio. The single-ended low frequency amplifier works similar to the historic
tube radio template. Your nostalgic radio uses a two-level transistor amplifier
with medium volume at low battery voltage. Now, two 1.5 V alkaline batteries are
sufficient for up to 100 hours of radio reception. Your self-made radio will make
listening to the radio even more fun. Enjoy the diversity of the VHF stations.
Components
Pre-equipped PCB with TDA7088
rod aerial
speakers 8 O, 0.5 W
volume control 22 kOwith switch
tuning control 22 kO
insulated wire
battery compartment with connection wires
T1 PNP transistor BC557B
T2 NPN transistor BC547B
Assembly of the Control Elements
The radio has two rotary controls. One for frequency and one for volume. The
volume controller with three connections additionally also carries the on/off
switch with two connections. If you turn the axis all the way to the left, the
switch opens. Place the volume controller in the left assembly hole. A small tab
prevents twisted insertion. Attach the control with the ring nut and do not forget
the washer.
The volume control (poti) with switch
The second potentiometer (poti) with 22 kΩ is used for frequency tuning. It is in-
stalled on the right. The connections for both potis should point inwards so that
the PCB can be installed between them later. Then screw the two rotary controls
onto the axes so that the end stops correspond to the printed scales.
Insert the speaker by pushing it into the matching slot. The connections should
point upwards to keep the connections to the PCB short later. The speaker will
be anchored sufficiently firmly in its intended slot. However, you can also apply
an additional drop of adhesive or hot glue.
6
Speaker
Screw the solder eye to the base of the telescopic aerial. Then push the aerial
through the casing opening from the inside and push the end into the flat holder,
which you have to attach properly in the casing with the included adhesive tape.
The aerial is then installed sufficiently firmly, but can later be additionally at-
tached with some adhesive tape.
The aerial
7
Soldering
The PCB already contains many soldered-on SMD components (surface-mounted
device): the receiver IC TDA7088, 15 capacitors and one resistor. Only a few of
these components still must be soldered in with connection wires. This includes
all components of the NF amplifier, the coils and components around the radio’s
diode tuning.
The SMD components
Now the PCBs are soldered together. The circuit diagram of the complete receiver
on the last page of this manual serves orientation purposes. For a small solder-
ing course, see the online magazine ELO (www.elo-web.de).
Components on the PCB
Equip the PCB with the electronic components according to the equipment plan.
First install the two coils SP1 and SP2.
8
Both coils must be made of the included equipment wire. Each of them has
three turns with an inner diameter of 5 mm and a length of approx. 7 mm. Use
the 100-µF-Elko as a coiling mandrel. First wind three turns close to each other.
Then draw the turns apart so that the coil has a total length of approx. 7 mm. Ac-
curacy does not need to be perfect, because the coil can still be changed a little
after installation. Strip the wire ends of insulation. Remove the coil from its coil-
ing mandrel only after this. Solder on the two wires at the bottom. Then cut off
protruding wires with sharp pliers about 2 mm above the PCV.
Coil installation
Insert the resistors R1 (4.7 kO, yellow, violet, red), R2 (220 kO, red, red, yellow)
close to the connections for Poti PT2. The resistors R3 (1 kO, brown, black, red),
R5 (330 kO, orange, orange, yellow) and R6 (33 O, orange, orange, black) belong
to the LF amplifier on the other side of the PCB. The resistor R4 (5.6 kO) is al-
ready soldered on as an SMD component. Bend the connection wires appropri-
ately for standing installation.
The resistors
9
The varactor diode D1
Now solder in the electrolyte capacitator C15 (100 µF). Observe installation direc-
tion. The plus pole is marked on the PCB. The minus pole is marked with a white
dash. It points towards the IC. Then install the ceramics of the capacitator C17 with
100 nF (print: 104). The installation direction is not important.
The capacitators
Last, you need to install the transistors. Do not swap the two types. T1 is a PNP
transistor BC557B, T2 is an NPN transistor BC547B.
10
Indice
Altri manuali Conrad Radio
