CB receiver

TECHNICAL 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.
    1. Connect a piece of cable around in the one metre in the place of aerial.
    2. Be supplied the receptor with + 12V and turn in half the potentiometer of regulation of sound (R12).
    3. 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..
    4. 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
electronic circuit
Source: www.electronics-lab.com
Published on: 2005-02-03
Reads: 3699
Print version: Print version

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