RF010

                                          

CB Receiver
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Schematic design of CB Receiver
Part List:
Capacitors	Resistors
C1               =  150 pF Ceramic C2               =   39 pF Ceramic C3,5            =   12 pF Ceramic C4               =   56 pF Ceramic C6-11,16,21  =   47 nF Ceramic C12,19         =   47 μF / 16V Electrolytic C13, 14        =   10 nF Ceramic C15             = 100 nF Polyester C17             =   10 μF / 16V Electrolytic C18             =  2.2 μF / 16V Electrolytic C20             = 470 μF / 16V Electrolytic Diodes D1                = AA119 or AA117 Semiconductors Q1,2    = BF241 U1       = LM386 Others Y1,2    = Crystal (You can put the so much, those               who also channels that you want to               touch). LS1     = Loudspeaker 8 Ω / 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.	R1,3,5   =    100 Ω ¼W R2         =   56K Ω ¼W R4         =   39K Ω ¼W R6         =    560 Ω ¼W R7,11    =   6.8K Ω ¼W R8         =    220 Ω ¼W R9         =   2.2K Ω ¼W R10       =   5.6K Ω ¼W R12       =    10K Ω Log. Potentiometer R13       =      1K Ω ¼W R14       =       10 Ω ¼W Inductors MF1     = Medium Freq. 455KHz core yellow * MF2     = Medium Freq. 455KHz core white * MF3     = Medium Freq. 455KHz core black * L1,2     = Wires of coper with diameter 0,4mm               wrapped in plastic support of diameter               6-7mm of core. For the L1 you wrap 13               coils. For the L2 you wrap 4 coils. * Intermediatte frequencies MF1-3 you can him   find in a old radio AM.
Technical Data
Tendency of cateringe:.................................+ 12V DC Frequency of reception at AM:.........................~27 MHz
Notes
For the regulation needs a transmitter or generator in transmission 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 microphones, you lower little the intensity of loudspeaker or you remove the transmitter from the receptor. The receptor this can combine itself with the transmitter CB in order to you manufacture a complete station CB. Modification: If you cannot find crystal 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 - 40 pF Trimmer

Source : Electronics Lab