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FM (Frequency Modulation) Transmitter Circuits, page 1
Last Updated on: Thursday, October 30, 2014 09:22 AM

FM Transmitters:  #'s       A - B      C - E     F       G -  M      N - Q      R - S       T - Z

Links to electronic circuits, electronic schematics, designs for engineers, hobbyists, students & inventors:

0.1 - 3.5GHz Prescaler -  This handy prescaler divides input frequency by 1000. It takes maximum input frequency of 3.5GHz and converts it into 3.5MHz that may be measured using standard frequency meter.
0-500MHz PIC16F876 RF Power Meter -  RF Measurement has been an expensive work so far the cost of measuring instruments are concerned. RF Meter is based on PIC16F876 microcontroller, AD8307 and 2x20 LCD display. Full documentation is included.
1 Watt Four Stage FM Transmitter -  This FM transmitter circuit uses four radio frequency stages: a VHF oscillator built around transistor BF494 (T1), a preamplifier built around transistor BF200 (T2), a driver built around transistor 2N2219 (T3) and a power amplifier built around transistor 2N3866 (T4). A condenser microphone is connected at the input of the oscillator.
1 Watt RF Amplifier -  This is a universal 1 Watt RF class C amplifier that is ideally suited for low power FM transmitters. Input should be at least 100mW to achieve 1W output. It is recommended to enclose the amplifier in a metal case.
1.5V Battery operated FM rebroADCast transmitter  -  This implementation is adapted to rebroadcast the output of a CD player, television receiver, or radio receiver. I use it so that I can move about the house and listen to my favorite programs without disturbing others. Within and the house,.....

1.5W VHF Amplifier -  This project will explain the basic function of a class-C transmitter. I will explain how to dimension a transmitter and the purpose of the different components. I will also explain how you can build a 1.5W PA transmitter. The project will include PCB,.....(schematic design added 03/08)
100W FM AmplifIER -  This Power amplifier is equipped with a bipolar transistor,the famous MRF317 As lots of FM amplifier application ,the power transistor is in a C class bias. All the impedance networks (Input & Output) have been determined by using the…(Circuit design added 06/07/08) [Michel P's website]
150mW FM Transmitter -  Electroinic circuit design…. [from Harry Lythall's website]
15dB UHF TV Antenna Booster -  This is an UHF band TV antenna preamplifier circuit With 15dB gain to build easily. It is formed based on BF180 UHF Transistor. The first stage is an band pass filter constructed by the C1, CV1, L1, L4, C7 and C3, the second stage is a base-common…(electronic design added 08/08/08)
15W Fm-transmitter -  Building a good fm-transmitter(88-110Mhz) begins with getting a good schematic. You don't have to understand the precise working of the transmitter to build it. But some basic information won't harm. A transmitter alone is, as you probably know, is not.....(electronic design added 08/08/08)
1GHZ Frequency Meter -  This is 1GHz frequency counter with 100KHz resolution. Meter is built in around PIC16F84A microcontroller and SAB6456 / U813BS prescaller.....(electronic circuit added 07/07/07)
1-transistor FM Transmitter -  A truly minimalist circuit. Performance is relatively poor and stability is a problem. Q1 modulates  signal and acts as an oscillator. L1 and C5 determine  frequency. Decrease C5 for a higher frequency and vice-versa. You won't get a long range transmission with this one.....(added 10/05)
1W Linear FM Booster -  This RF Amplifier is used for boosting small fm transmiters and bugs. It use two Philips 2N4427 and its power is about 1Watt. At the output you can drive any linear with BGY133 or BLY87 and so on. Its power supply has to give 500mA current at 12 Volts. More voltage can boost the distance but the transistors will be burned much earlier than usual.! In any case do not exceed the 15Volts. The Amp offers 15 dB in the area of 80Mhz to 110 Mhz. L4, L5, and L6 are 5mm diameter air coils, 8 turns, with wire 1mm wire diameter.An easy project, with great results.….(electronic schematic added 12/08)
1W PLL FM Transmitter -  The VERONICA transmitter is a very stable, powerful, and high quality FM emitter. Thanks to a PLL, the output frequency is controlled with DIP switches. Output power is approximatively 1W with a single regulated 13.8v supply ! (see specifications) Features : * High RF output power : 1W * Full 87.5-108MHz range (100KHz increment). * Very stable output frequency : Crystal reference & Phase Locked Loop. * Professional input bandwith (fully RDS compatible ) * No complex tuning needed. * High quality PCB * Full documentation & construction details available.….(Circuit design added 12/08)
1W Portable PLL transmitter -  This small FM transmitter includes a limiter, a microphone amplifier and a PLL digital tuning. All the parts are placed on one circuit board. The RF power is switchable between 1W and 0,2W. (electronic circuit added 08/08/08)
1W RF Power Amplifier for iPOD Stereo FM transmitters -  This map, armored also enables automatic MONO / MPX through a low-pass filter, even with a multiplex on its entry by using an ON / ON, panning, the whole spectrum MPX more RDS is sent to the synthesizer, on the other hand when it is in a position MONO, the low-pass filter is activated and share its cutoff frequency at 15 KHz, only modulation G + D is sent to the synthesizer, as 19 KHz. 19 KHz carrier, the signal multiplex and subcarrier 57 KHz is thereby eliminated, which provides ease of use for example in a string of issue relay tuner, if the link between the issuer Departure and receiver re-issue was not of good quality stereo, you sufficient to switch to mono to improve sound quality, you can then connect the RDS encoder at the re-issuer. ….(electronic schematic added 11/08)
1W-5W FM Transmitter -  The Veronica is an easy to build and tune transmitter for the FM band. It's known for it's stability and clean signal, does not use any IC's or similar specialized parts, and it has a built-in tuning aid that makes it possible to tune it with no extra equipment. It's available in two versions, 1 and 5 watts.….(Circuit design added 12/08)
2 Transistor FM Transmitter -  A compact 2 transistor transmitter for use at VHF frequencies.… [Andy Collison, designer]
2 Transistor FM Transmitters (Bill Bowden) -  (electronic Circuit added 03/06)
20W FM Amplifier -  This Power amplifier is equiped with two Philips bipolar transistors : the BLV10 & BLW87. As lots of FM amplifier design, the RF transistors are in a class C bias. The FM amplifier has a 21 dB gain with a 55 to 65% efficiency…(circuit added 04/08).
25W RF Amplifier -  RF amplifier with 25W of power for 88-108MHz FM transmitters.….(Circuit design added 12/08)
27MHz/ 49 MHz Walkie Talkie -  Lots of people are requesting walkie-talkie and RF remote control schematics, so here is some. Building these circuits needs special equipment and expertise in RF circuits. If you are going to experiment with these circuits, please..... [Peter Jakab, Electrical Engineer, Engineer of Informatics]
2W RF Amplifier For 24/23 CM -  This page describes TX ATV Transmitter for 23 cm with output adjustable from 100 to 250mW.
3 Transistor FM Transmitters -  While re are a plethora of similar 2-transistor schematics available, this one is above average. A major improvement over  little 1-transistor circuit that we've discussed previously, this transmitter consist of two stages.  first transistor is used to amplify audio,.....(added 3/06)
300 MHz Prescaler -  A preamp that drives the CMOS counter input and a divide by 10 prescaler to extend the range of A Little More Serious Frequency Meter. The MCT10280 prescaler can be set to divide by 80, 40, 20, or 10, as a function of which pins are tied to the power supply. I set this one to divide by 10 since it is adequate for my needs, and the mental calculation of multiplying the meter reading by 10 is not taxing. One problem with the MCT10280 is that if it doesn't have an adequate input, the output is very noisy, which shows up as counts in the couple MHz range on the frequency meter.  This noise shows up if the signal amplitude the signal frequency is too low. For this reason, I only intend to use the prescaler with inputs between 10 MHz and 300 MHz.….(electronic schematic added 12/08)
30W VHF FM Amplifier for 88-108 MHz with BLF245 MOSFET -  The achievement of this 30-watt amplifier has been designed to take place on a heatsink microprocessor PC equipped with its fans, the advantage of this method of cooling has been selected for the fact that …(French schematic added 08/08/08)
3V FM Transmitter for 88MHz to 108MHz -  The important part of the circuit is formed of the Colpitts type oscillator. C3,C4,C5,C6,CD1-CD2 and L1 determines the frequency. BF982 and dual gate MOSFET are active parts in oscillator. When the input impedance of the MOSFET gate inputs are high, LC tank is not affected. However transistors force the LC tank and cause phase shift. Two driver stages are added to isolate the antenna from oscillator. First stage (BF199) amplifies the low signal of the oscillator and works as a constant load. The second stage (BFR90) amplifies the signal going through the antenna some more. A short copper wire can be used as an antenna here. Attaching a large antenna to this circuit is unnecessary because the output power is low.….(Circuit design added 12/08)
3W FM Transmitter -  This is the schematic for an FM transmitter with 3 to 3.5 W output power that can be used between 90 and 110 MHz. Although the stability isn't so bad, a PLL can be used on this circuit.  This is a circuit that I've build a few years ago for a friend, who used it in combination with the BLY88 amplifier to obtain 20 W output power. From the notes that I made at the original schematic, it worked fine with a SWR of 1 : 1.05 (quite normal at my place with my antenna). (electronic circuit added 08/08)
4 Transistor Transmitter -  This circuit provides an FM modulated signal with an output power of around 500mW. The input Mic preamp is built around a couple of 2N3904 transistors, audio gain limited by the 5k preset. The oscillator is a colpitts stage, frequency of oscillation governed by the tank circuit made from two 5pF capacitors and the inductor.... Design by Paul K Sherby]
4 Watt FM Transmitter -  This is a small but quite powerful FM transmitter having three RF stages incorporating an audio preamplifier for better modulation. t has an output power of 4 Watts and works off 12-18 VDC which makes it easily portable. It is the ideal project for the beginner who wishes to get started in the fascinating world of FM broadcasting and wants a good basic circuit to experiment with.....
4 Watt FM Transmitter-2 -  Schematic and notes
40 Meter Direct Conversion Receiver -  .....
40 Meter, 5 Watt QRP Transmitter -  As ham operators, we like to broaden our horizons by trying something new. There is nothing more satisfying about this hobby than building your own transmitter. The circuit in figure 1 is a crystal controlled CW transmitter with at least 5 watts of power. (The prototype generated 7 ˝ watts)This circuit was built on a Radio Shack universal board (276-168B) and worked extremely well the first time..... [Radio Amateur Society of Norwich]
400mW VCO FM transmitter -  BF199, BFR91, BFR96, varicap diode BB109.  (circuit added 8/06) 
4-Transistor Transmitter (Paul C. Sherby) -  This circuit provides an FM modulated signal with an output power of around 500mW.  The input microphone pre-amp is built around a couple of 2N3904 transistors (Q1/Q2), and audio gain is limited by the 5k preset trim potentiometer. The oscillator is a Colpitts stage, frequency of oscillation governed by the tank circuit made from two 5pF ceramic capacitors and the L2 inductor..... [Tony van Roon's circuit]
5 Watt FM Amplifier -  This design is a 2 stage amplifier that has about 17db of gain, suitable for an input of 50 to 100 MW. Its basically a Veronica 5 watt vco transmitter, without the vco. The transistors are a 2N4427 and a MRF237. Output power is 2.5 to 5 watts, depending on input drive and dc voltage. At 13.7 vdc with 50 MW of drive, the output was 2.5 watts. The maximum dc voltage recommended is about 15-16 volts.
5 Watt UHF TV Amplifier -  This small circuit is a Linear amplifier for driving small UHF TV transmitters. Its gain is 7dB and can amplify a signal between 450-800 MHz. You can drive the circuit with 1 to 1,5 Watts signal. Better use double layer PCB with the second layer connected to earth.....(electronic design added 08/08/08)
5W PLL Stereo Transmitter with LCD -  Here's PLL FM transmitter circuit from china.  This circuit uses the familiar 2SC1971 for final power amplifier stage. …(electronic circuit added 08/08/08)
81 Watt FM stereo transmitter -  A high quality broadcast transmitter big enough for a medium town! [Manfred Mornhinweg]
8W PLL Stereo Transmitter with LCD -  Very stable FM transmitter based on TSA5511 synthesizer. Frequency is performed with three buttons through PIC16F84 microcontroller. Frequency is displayed on 16x1 LCD.….(design added 12/08)

FM Transmitters:  #'s       A - B      C - E     F       G -  M      N - Q      R - S       T - Z

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