Rangkaian Power Amplifier Pemancar FM 4-20 Watt Rangkaian Power Amplifier Pemancar FM 4-20 Watt

Rangkaian Power Amplifier Pemancar FM ini sangat sederhana, namun kualitasnya cukup memuaskan.

A very simple fm power amplifier which can deliver 4W rf power with 12V power supply and BLY87A or KT920A and 20W with BLY89A or KT925B.
If you use BLY87A or KT920A the input power must be 0.5W and 4W if you use BLY89A or KT925B. This fm power amplifier is designed to work on 50 Ω antennas and a maximum power supply of 14V and in 88 108 MHz band.
Use only metallic trimmers, a good heatsink for the transistor and ceramic capacitors and keep the pins very short.
FM power amplifier circuit components:
C1 = C8 = 10-40pF + 22pF in parallel ||
C2 = 10-70pF + 120pF ||
C3 = 2.2nF
C4 = 33nF
C5 = 4 x 180pF
C6 = 1nF
C7 = 2.2nF
C9 = 10-70pF + 47pF ||
R1 = 380Ω
R2 = 47Ω
R3 = 5.6 Ω
L1 = 3 turns / 0.8mm / 6mm / legth = 8mm
L2 = 6turns / 0.5mm /over R2
L3 = 5 t / 0.6mm / 6mm
L4 = 4 t / 1.2mm / 8mm
T = 4W with BLY87A, KT920A
T = 20W with BLY89A, KT925B

FM amplifier circuit schematic

 Source: http://electroschematics.com

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Kit Pemancar FM Setereo IC BA1404 Kit Pemancar FM Setereo IC BA1404

Jadilah "On Air" dengan stasiun radio sendiri! Pemancar FM Ini merupakan produk menarik yang akan menyiarkan sinyal stereo berkualitas tinggi dalam 88 - 100MHz FM band. Hal ini dapat dihubungkan ke semua jenis sumber audio stereo seperti komputer pribadi, CD player, walkman, televisi, tape deck atau sistem stereo untuk mengirimkan suara stereo dengan kejelasan yang sangat baik di seluruh, kantor Anda pekarangan rumah, atau tanah kamp.
Hal ini juga dapat digunakan dalam mobil untuk memutar CD melalui radio mobil Anda ketika melekat pada CD player pribadi. Aplikasi lain dapat mendengarkan stasiun radio satelit melalui radio FM. Selain itu, dapat dihubungkan ke komputer pribadi atau laptop untuk memungkinkan mendengarkan stasiun radio internet atau pra-rekaman musik digital (seperti file MP3).



Sirkuit yang mencakup snap baterai 9V dan stereo 3.5mm jack dipasang tepat di papan tulis untuk koneksi yang mudah ke sumber audio. Sebuah ON / OFF serta "On-Air" indikator LED juga dimasukkan di papan tulis.
 

Source : http://home.maine.rr.com/randylinscott/feb98.htm

   
Rangkaian ini didasarkan pada IC BA1404 penyiar stereo populer yang berisi semua sirkuit kompleks untuk menghasilkan sinyal FM stereo. Sebuah kristal KHz 38 menyediakan stabil sub-carrier untuk sinyal stereo. Rangkaian osilator cukup stabil untuk penerimaan handal bahkan di radio FM digital disetel. Penyesuaian input terpisah kanan dan kiri tingkat juga disertakan.

Untuk memperoleh Kit ini anda bisa membelinya di CAR'L ELECTRONICS 

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Pemancar FM menggunakan Op-amp Pemancar FM menggunakan Op-amp

Sebuah Transmitter FM daya rendah menggunakan sebuah op-amp sebagai preamp audio dan satu transistor sebagai penguat RF.

List Component:

R1 4K7        R4 150K     R7 3K9 (2K7)

R2 4K7        R5 220R     R8 120R (82R)

R3 4K7        R6 4K7

All resistors except R8 are at least 0.25W rated. R8 is at least 0.5W rated
(the 0.6W metal film M-series from Maplin can be used for R1-R8).

C1 1n         C4 22uF         C7 10n         C10 1n

C2 4u7        C5 1n           C8 1n

C3 1n         C6 10n          C9 33pF

VC1 5-60pF         IC1 LM358         Q1 ZTX108

Notes
L1 is 0.112uH (this tunes to the middle of the FM band, 98 MHz, with VC1 at its centre value of 33pF).

L1 is 5 turns of 22 swg enamelled copper wire close-wound on a 5mm (3/16") diameter former. Alternatively, you can have a fixed 33pF cap instead of VC1 and have L1 as an adjustable molded coil (eg UF64U from Maplin). VC1 will give you a tuning range of 85 - 125 MHz, and a possible choice is the Philips type polypropylene film trimmer (Maplin code WL72P).

Two sets of oscillator bias resistors are given, the ones in the brackets give about 20% more RF power.

Mike is our favourite Omnidirectional sub-mini electret (Maplin code FS43W). Ant is a (lambda / 4) whip monopole (eg 76 cms of 22 swg copper wire).

Q1 is configured as a Clapp oscillator. Frequency modulation results from the audio voltage changing the transistor's base-emitter capacitance.

Source:  http://www.zen22142.zen.co.uk

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2 Watt FM Transmitter 2 Watt FM Transmitter

The circuit is basically a radio frequency (RF) oscillator that operates around 100 MHz. Audio picked up and amplified by the electret microphone is fed into the audio amplifier stage built around the first transistor. Output from the collector is fed into the base of the second transistor where it modulates the resonant frequency of the tank circuit (L1 coil and the trimcap) by varying the junction capacitance of the transistor. Junction capacitance is a function of the potential difference applied to the base of the transistor T2. The tank circuit is connected in a Hartley oscillator circuit.

Components List

R1=220K R2=4.7K R3,R4=10K R5=100ohm

C1,C2=4.7uF Electrolytic C3,C4=1nF C5=2-15pF C6=3.3pF

Q1=BC547C Q2=BD135 P1=25K MIC=Electret Condenser Type

P1 act as condenser microphone volume level. For FM, coil will be small. Use thin gauge enamel magnet wire. the diameter of coil will be a couple mm: use ink tube from pen to form, and try 8-12 turns. Small inductance coils make for much guess work.

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Stereo FM Transmitter Based BH1417 Chips Stereo FM Transmitter Based BH1417 Chips

This electronic circuit is a latest BH1417 FM Transmitter design from RHOM that includes a lot of features in one small package. It comes with pre-emphasis, limiter so that the music can be transmitted at the same audio level, stereo encoder for stereo transmission, low pass filter that blocks any audio signals above 15KHz to prevent any RF interference, PLL circuit that provides rock solid frequency transmission (no more frequency drift), FM oscillator and RF output buffer.

There are 14 possible transmission frequencies with 200KHz increments that users can select with a 4-DIP switch. Lower band frequencies start from 88.7 up to 89.9 MHz, and upper band frequencies start from 107.7 up to 108.9 MHz.


BH1417 can be supplied with 4 - 6 voltage and consumes only around 30mA, providing 20mW output RF power. BH1417 provides 40dB channel separation which is pretty good, although older BA1404 FM Transmitter chip provides slightly better 45dB channel separation.


BH1417 is only available in SOP22 IC case so this may be an inconvenience for some folks. On the other hand, because the chip is smaller than regular DIP-based ICs it is possible to fit the entire transmitter on a small PCB.

The bad news is that BH1417 requires 7.6MHz crystal oscillator, which is very hard to find. The good news is that you can use 7.68 MHz crystal instead, which is easier to find. In fact our BH1417 transmitter prototype (schematic shown above) uses 7.68 MHz crystal. This has absolutely no effect on stereo encoding process, we have tested it and stereo sound is crystal clear. The transmitted frequency on the other hand will be shifted up by exactly 1MHz (example: 88.1 MHz to 89.1 MHz) which is perfectly fine. The frequencies that are used in this project have been adjusted by 1MHz already so no additional conversion is necessary.

BH1417 chip may also be used a stand alone stereo encoder. The advantage of that is that you have full freedom of using a transmitter & amplifier of your choice. You will still have a pre-emphasis, limiter,stereo encoder and low pass filter in one small package because very few external components are required for these blocks. PIN 5 is MPX output that can be directly connected to an external FM transmitter through a 10uF cap.


Parts List:
1x BH1417 - Stereo PLL Transmitter IC (Case SOP22) (datasheet)
1x 7.68 MHz Crystal
1x MPSA13 - NPN Darlington Transistor
1x 2.5 Turns Variable Coil
1x MV2109 - Varicap Diode
1x 4-DIP Switch
ANT - 30 cm of copper wire

1x 22K Resistor
7x 10K Resistor
1x 5.1K Resistor
2x 3.3K Resistor
1x 100 Ohm Resistor 1x 100uF Capacitor
3x 10uF Capacitor
2x 1uF Capacitor

1x 47nF Capacitor
3x 2.2nF Capacitor
1x 1nF Capacitor
1x 330pF Capacitor
2x 150pF Capacitor
1x 33pF Capacitor
2x 27pF Capacitor
1x 22pF Capacitor
2x 10pF Capacitor

Specifications:
Supply Voltage: 4 - 6V
Transmission Frequency: 87.7 - 88.9MHz, 106.7 - 107.9MHz (200kHz steps)
Output RF Power: 20mW
Audio Frequency: 20 - 15KHz
Separation: 40dB
Power Consumption: 30mA

Frequency Selection / Calibration
Frequency selection is very straight forward. Simply select transmission frequency at which you would like to transmit, set the combination for 4-DIP switch and BH1417 will immediately tune to that frequency. If you can't hear the transmitted audio signal on your FM receiver then re-adjust 2.5 turn variable coil until you can hear the signal. If you have a laboratory power supply you may try to vary the voltage supply from 4 to 6V. While doing that BH1417 will automatically vary the voltage for MV2109 varicap diode making sure that there's no frequency drift.

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FM Transmitter (Pemancar FM) FM Transmitter (Pemancar FM)

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