“ CAR’S RADIO WITHOUT ANTENNA ”

1.1              INTRODUCTION

In the present era, the various technologies we can see. On average, every three months there is a new technology. So not supprisingly, with so many unique and innovative equipment trigerred. “ Car’s radio without antenna”  are our project. This is an idea from development of  handphone. We can see the development of handphone from the  radiophones have a long and varied history going back to Reginald Fessenden's invention and shore-to-ship demonstration of radio telephony, through theSecond World War with military use of radio telephony links and civil services in the 1950s until now.

So we want to create the new development of radio that do not use the external antenna. Furthermore, it can solving the problem for radio too. In this proposal, discusses the design and circuit design of this tool. “ Car’s radio without antenna” 

1.2              PROBLEM  STATEMENT

v  Broken antenna

v  Loss of antenna

v  Interference from corona effect

v  Too many station radio

v  Always the case noise

1.3              OBJECTIVE

v  Accentuate the car design

v  Reduce the maintenance cost

v  To get the clear boardcast that we want to hear

v  To prevent from any interference of frequency

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1.4              SCOPE OF PROJECT

v  Create a new radio’s car without antenna

v  Using booster to increase signal

v  Create a simple crcuit to place it only in radio

v  This project using a power supply from car’s battery

CHAPTER 2

LITERATURE REVIEW

This radio’s car without antenna functioning by using three main content which are FM booster, internal antenna and the original circuit of radio without the antenna.  There are content of this project:

1.      FM booster schematic diagram

 FM booster that can be used to listen programs from distant FM stations clearly. The circuit comprises a common-emitter tuned RF preamplifier wired around VHF/UHF transistor 2SC2570 ( C2570).
This FM booster circuit is constructed using few common components ( not require some special components ) and provide a very good gain .
To calibrate this circuit you need to adjust input/output trimmers (VC1/VC2) for maximum gain.
Input coil L1 consists of four turns of 20SWG enamelled copper wire (slightly space wound) over 5mm diameter former.

It is tapped at the first turn from ground lead side. Coil L2 is similar to L1, but has only three turns.
Both of the trimmers are 22pF value .This FM radio signal booster needs to be powered by a 12 volts DC power supply .

2.      Original car radio circuit

We will connect the internal antenna to the booster and go to RF. Then the LNA will boost the signal one more time. Its mean the signal will be boosting twice. So we can get the great frequency.

3.      Internal antenna

We will create the internal antenna by using the copper plate and place it upper part inside the radio.

CHAPTER 3

METHODOLOGY

3.0       Introduction

In this chapter we will describe the project components are used, the flow of projects, operation of the circuit, and software programs are used together with a block diagram of the entire project.

3.1       Components of the Project

            3.1.1    Resistors

            The resistor is a component that limits the current flow. Resistor selection is made according to its suitability for use in the circuit. When selecting resistors, four in the table below should be considered.

Table 3.1: Things to consider when choosing a resistor.

Num.	Subject	Function
1.	The resistance	The resistance can be read either by using color codes or cards printed on the resistor body
2.	Tolerance	Tolerance indicates the minimum and maximum value of the resistor.
3.	Rated power	Size of the resistor indicates the maximum power that can be accepted by the resistor.
4.	Stability	Resistors with high stability can be maintained barrier with changes in temperature and lifetime.

The resistor is divided into two categories: fixed resistors and variable resistor.

a)      Fixed Resistors

        Fixed resistor is the resistor resistance value is not changeable. However, factors such as changes in temperature, the material may flow resistor or the resistance to change remains. The resistance can be specified by color code or a printed card. The resistance of a resistor can be determined by interpreting the color lines are printed on the body. Usually there are four lines are printed on the resistor body. The first and second strip shows the first digit and second digit. The third path is the value of the multiplier. The fourth path is tolerance. Interpretation by the code set is shown in Table 3.2.

In this project we use several types of resistors. For our power supply circuit using a 470Ω resistor value of 1K and while the circuit is "relay card" we use a resistor value is 39Ω for the circuit and PIC (Micro Program Controller) is valued resistors 50Ω and 500Ω. Figure 2.1 shows examples of resistors used in the circuit.

      Figure 3.1: Resistor

Capacitors are components that store electrical charges. Basically, a capacitor consists of two metal plates, or two parallel conductors separated by an insulator called a dielectric. This dielectric may comprise air, paper, mica, polyester or electrolytic. Figure 2.2 shows the construction of a capacitor.

Capacitor in the circuit function is to store charge temporarily, and it can be charged and discharged. Figure 3.3 shows the type of capacitor used in the circuit PIC (Micro Program Controller).

Figure 3.3: Capacitor

3.1.2        Trimmer   capacitor

Trimmer capacitors (trimmers) are miniature variable capacitors. They are designed to be mounted directly onto the circuit board and adjusted only when the circuit is built.

A small screwdriver or similar tool is required to adjust trimmers. The process of adjusting them requires patience because the presence of your hand and the tool will slightly change the capacitance of the circuit in the region of the trimmer!

Trimmer capacitors are only available with very small capacitances, normally less than 100pF. It is impossible to reduce their capacitance to zero, so they are usually specified by their minimum and maximum values, for example 2-10pF.

Trimmer Capacitor Symbol

This type of variable capacitor (a trimmer) is operated with a small screwdriver or similar tool. It is designed to be set when the circuit is made and then left without further adjustment. To calibrate this circuit you need to adjust input/output trimmers (VC1/VC2) for maximum gain.

3.1.3        Inductor coil

An inductor is simply a coil of insulated wire. The strength of its inductance depends on several factors, including how many turns of wire are in the coil, and whether the coil surrounds an iron core. A coil of wire which creates a magnetic field when current passes through it. It may have an iron core inside the coil. It can be used as a transducer converting electrical energy to mechanical energy by pulling on something.

Filter

Simple circuits made of an inductor, capacitor and resistor can enhance a particular signal frequency. For example, a radio uses this circuit to tune in different stations. An inductor on its own can filter out frequencies that are higher or lower than the one it's tuned to.

Transformer

Two inductors, placed closely together, make up a transformer. A transformer can isolate unwanted direct current (DC) signals, or increase or decrease the voltage in an alternating current (AC) signal. Transformers reduce wire losses for electrical power distribution, making electricity more affordable.

Oscillator

The same inductor circuits used to amplify existing signals can also be used to generate new ones. A circuit that does this is called an oscillator, and it is used to broadcast television and radio channels at millions of cycles per second.

Choke

Simple inductor circuits, called chokes or traps, eliminate interfering frequencies from radio and television signals. For example, you can use a choke to keep a nearby police radio transmission from getting into your normal radio channels.

Solenoid

A solenoid is an electromechanical device consisting of an inductor and a spring-loaded iron core. When you put a DC current through a solenoid, the inductor pulls the core inside. The iron core, when connected to other parts of a machine, can act as an electrically-activated gate or trigger.

In this project, input coil L1 consists of four turns of 20SWG enamelled copper wire (slightly space wound) over 5mm diameter former.

It is tapped at the first turn from ground lead side. Coil L2 is similar to L1, but has only three turns

3.1.4        Transistor

A transistor is a semiconductor device used to amplify and switch electronic signals and power. It is composed of a semiconductor material with at least three terminals for connection to an external circuit. A voltage or current applied to one pair of the transistor's terminals changes the current flowing through another pair of terminals. Because the controlled (output) power can be much more than the controlling (input) power, a transistor can amplify a signal. Today, some transistors are packaged individually, but many more are found embedded in integrated circuits.

The transistor is the fundamental building block of modern electronic devices, and is ubiquitous in modern electronic systems. Following its release in the early 1950s the transistor revolutionized the field of electronics, and paved the way for smaller and cheaper radios, calculators, and computers, among other things.

There are two types of transistors, which have slight differences in how they are used in a circuit. A bipolar transistor has terminals labeled base, collector, andemitter. A small current at the base terminal (that is, flowing from the base to the emitter) can control or switch a much larger current between the collector and emitter terminals. For a field-effect transistor, the terminals are labeled gate, source, and drain, and a voltage at the gate can control a current between source and drain.

The image to the right represents a typical bipolar transistor in a circuit. Charge will flow between emitter and collector terminals depending on the current in the base. Since internally the base and emitter connections behave like a semiconductor diode, a voltage drop develops between base and emitter while the base current exists. The amount of this voltage depends on the material the transistor is made from, and is referred to as V_BE.

Transistor as a switch

Transistors are commonly used as electronic switches, both for high-power applications such as switched-mode power supplies and for low-power applications such as logic gates.

In a grounded-emitter transistor circuit, such as the light-switch circuit shown, as the base voltage rises, the base and collector current rise exponentially. The collector voltage drops because of the collector load resistance (in this example, the resistance of the light bulb). If the collector voltage were zero, the collector current would be limited only by the light bulb resistance and the supply voltage. The transistor is then said to be saturated - it will have a very small voltage from collector to emitter. Providing sufficient base drive current is a key problem in the use of bipolar transistors as switches. The transistor provides current gain, allowing a relatively large current in the collector to be switched by a much smaller current into the base terminal. The ratio of these currents varies depending on the type of transistor, and even for a particular type, varies depending on the collector current. In the example light-switch circuit shown, the resistor is chosen to provide enough base current to ensure the transistor will be saturated.

In any switching circuit, values of input voltage would be chosen such that the output is either completely off,^[21] or completely on. The transistor is acting as a switch, and this type of operation is common in digital circuits where only "on" and "off" values are relevant.

Transistor as an amplifier

The common-emitter amplifier is designed so that a small change in voltage (V_in) changes the small current through the base of the transistor; the transistor's current amplification combined with the properties of the circuit mean that small swings in V_in produce large changes in V_out.

Various configurations of single transistor amplifier are possible, with some providing current gain, some voltage gain, and some both.

From mobile phones to televisions, vast numbers of products include amplifiers for sound reproduction, radio transmission, and signal processing. The first discrete transistor audio amplifiers barely supplied a few hundred milliwatts, but power and audio fidelity gradually increased as better transistors became available and amplifier architecture evolved.

Modern transistor audio amplifiers of up to a few hundred watts are common and relatively inexpensive

3.1.5        Copper board or plate

In this project we use the copper board or copper plate as a internal antenna.