Schematics > RF circuit > CB receiver
CB receiverTECHNICAL CHARACTERISTICS:
Tendency of catering: + 12V DC
Frequency of reception at AM: ~27MHz
Materially:
The resistances are 1/4W.
| R1, R3, R5 |
100W |
| R2 |
56KW |
| R4 |
39KW |
| R6 |
560W |
| R7, R11 |
6,8KW |
| R8 |
220W |
| R9 |
2,2KW |
| R10 |
5,6KW |
| R12 |
10KW logarithmic pontesiometer |
| R13 |
1KW |
| R14 |
10W |
| C1 |
150pF ceramic |
| C2 |
39pF ceramic |
| C3, C5 |
12pF ceramic |
| C4 |
56pF ceramic |
| C6, C7, C8, C9, C10, C11, C16, C21 |
47nF ceramic |
| C12, C19 |
47mF/16V electrolytic |
| C13, C14 |
10nF ceramic |
| C15 |
100nF polyester |
| C17 |
10mF/16V electrolytic |
| C18 |
2,2mF/16V electrolytic |
| C20 |
470mF/16V electrolytic |
| D1 |
AA119, AA117 (germanium diode) |
| Q1, Q2 |
BF241 (amplifiers of intermediary frequency) |
| U1 |
SO42P (mixed and local oscillator) |
| U2 |
LM386 (amplifier A.F.) |
| Y1, Y2 |
Crystals hails. (You can you put the so much,
those who also channels that you want you touch). See
here. |
| MF1 |
Medium frequency 455KHz, core yellow. * |
| MF2 |
Medium frequency 455KHz, core white. * |
| MF3 |
Medium frequency 455KHz, core black. * |
| L1, L2 |
Wires of coper (smaltwme'na) with diameter
0,4mm wrapped in plastic support of diameter 6-7mm of perjstrofjkoy' core.
For the L1 you wrap 13 coils. For the L2 you wrap 4 coils. |
| LS1 |
Loudspeaker 8W/1W. |
| ANT1 |
Aerial for CB (For the trials is enough a piece
wire of few metres). |
| S1 |
Switch of choice of channel. It has so much
places, those who also the channels that you want to touch. |
* Intermediary frequencies mf1-3 you can him find in a old radio AM.
Regulations:
For the regulation needs a transmitter or generator in mpa'nta the CB,
that is to say in the region 27MHz. If you have a certain friend with CB,
you convince you to help.
- Connect a piece of cable around in the one metre in the place of aerial.
- Be supplied the receptor with + 12V and turn in half the potentiometer
of regulation of sound (R12).
- Turn on the generator or the transmitter CB and you emit in distance of
10 metres roughly from the receptor, in the channel that receives the
receptor..
- From the loudspeaker it will be supposed it begins to be heard what you
emit and if it does not have big force, you turn the core of inductor L1/L2
until you have a increase of intensity. After this you can continue with the
various medium frequencies beginning from black (MF3) until you have the
biggest intensity. If it is heard mjkrofwnjsmo's, you lower little the
intensity of loudspeaker or you remove the transmitter from the receptor.
Modification:
If you cannot find krysta'lloys you can make the modification that shows the
form. That is to say, instead of crystal you in joint action put respectively
coordinated circuits with LC each one in different channel.
| L |
Same with the L1. |
| C |
4 - 40pF trimmer |
Notes:
The receptor this can combine itself with the transmitter CB in order to
you manufacture a complete station CB.
Title: CB receiver
Source: www.electronics-lab.com
Published on: 2005-02-03
Reads: 1198
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