Car antenna amplifier is a small box which helps car radio to catch signal better.
Radio signal sometimes are very weak like soft whisper where radio are not heard good.
Amplifier make whisper loud so radio can hear clear.
It is good for places where radio station is far or music have noise or crack sound.
Circuit Working:
Parts List:
| Component | Quantity |
|---|---|
| Resistors ( All resistors are 1/4 watt unless specified) | |
| 100Ω | 1 |
| 10k | 1 |
| 330Ω | 1 |
| 47Ω | 1 |
| 1kΩ | 3 |
| 22k | 2 |
| Capacitors | |
| Ceramic 100pF | 1 |
| Ceramic 0.001µF (1nF) | 1 |
| Ceramic 0.1μF | 3 |
| Semiconductors | |
| Transistors BC547 | 3 |
| Diodes 1N4148 | 2 |
| Antenna | 1 |
This amplifier for car antenna can work up to 70 MH which helps make weak signal more strong from the antenna.
It have high input impedance and make little noise.
Gain is around 30 dB which is at 30 MHz and input impedance is about 10 kilo ohm.
To stop signal loss from coax cable better to put amplifier right at bottom of antenna.
This amplifier is used only for fixed receiver not good for moving or driving use.
If one puts it outside on antenna please cover with waterproof box or rain can break it.
Important: This amplifier is only for receiving signal is anyone trys to send signal through it the parts can break.
Formula:
Making a circuit to boost weak RF signal from antenna is the job of building amplifier using BC547 transistors for car antenna.
Gain of Amplifier (Common Emitter type):
To guess voltage gain (Vg) we can use this:
Av = −RC / re
where:
- RC is resistor on collector side
- re is small resistance from emitter and we get it from: re = VT / IC
- VT is about 26mV at normal temperature
- IC is current going in collector
How transistors are connected and how we give bias will decide in actual gain.
Note:
With BC547 transistor this circuit gives simple base for making amplifier for car antenna.
But for better working in actual car radio or similar use one needs to test more and maybe change some parts.
How to Build:
To build a Simple Car Antenna Amplifier Circuit follow the below steps for connections and safety:
Choose Parts:
- Select the right parts based with the elements listed in the description and the frequency range one wants to use.
Make Circuit Design:
- We can draw circuit by hand or use circuit software.
- Be sure design is okay for frequency and impedance.
Create PCB Layout:
- Design PCB for ones circuit.
- Put parts on board same like in circuit diagram.
- Be careful with ground and RF wire to stop signal problem.
Build the Circuit:
- Solder all the parts on PCB one by one.
- Take care with small parts like transistor and capacitor whether they break easy.
Mount It:
- Put the amplifier close to car antenna base.
- Fix it well so it does not move or come loose.
Test It:
- Connect power and test with car antenna.
- Use RF tools like signal generator or spectrum analyzer to check the gain and frequency.
Final Check:
- After building and mounting test full circuit.
- See if it works good and match what is needed.
Note:
- Be safe while soldering and testing as RF circuits can be sensitive.
- Also check with all wire and parts again because small mistake can make amplifier not work good.s to avoid any errors that could affect the performance of the amplifier.
Conclusion:
Car antenna amplifiers are mostly placed near the antenna a very close to antenna base.
This help stop signal loss in coax cable that are connected to car radio.
Some amplifier circuits are made special for some antenna types or for certain frequency which are based on what the users want to use it for.
In general car antenna amplifier can make car radio work much better.
It help catch more stations and give more clear sound while driving.