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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….(schematic design added 08/08/08) |
|
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.….(circuit design added 12/08) |
|
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,...(added 08/08/08) |
|
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) |
|
150mW FM Transmitter - (electronic Circuit added 03/06) |
|
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-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 (Andy Collinson) - Take care with transmitter circuits. It is
illegal in most countries to operate radio transmitters without a license.
Although only low power this circuit may be tuned to operate over the range
87-108MHz with a range of 20 or 30 metres….(circuit added 10/09) |
|
2 Transistor FM Transmitters (Bill Bowden) - (electronic Circuit added 03/06) |
|
2 Transistor Transmitter - A compact 2 transistor transmitter for use at VHF
frequencies…..(electronic design added 6/07) |
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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 ....(circuit added 08/08/08) |
|
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) |
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4 Transistor Transmitter - (design added 8/03) |
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4 Watt FM Transmitter (tomzi.geo) - (electronic design added 6/07) |
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4 Watt FM Transmitter-2 - ….(circuit design added 03/08) |
|
40 Meter Direct Conversion Receiver - (electronic Circuit / Schematic added
10/04) |
|
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....(electronic circuit added 05/07) |
|
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) |
|
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) |
|
A bipolar regenerative receiver - Contrary to what some radio experimenters
think, a bipolar regenerative design can be made to work efficiently. The major
concern is the low input impedance of the detector-amplifier bipolar….(electronic
design added 6/07) |
|
A short wave regenerative receiver - Sensitivity and selectivity are the major
concerns of a short wave enthusiast when he looks up for a receiver. Commercial
communications models with superhet circuitry surely satisfy his requirements, but
these are expensive. He would rather go for a homebrewed radio, being a
regenerative receiver an affordable choice....(electronic design added 6/07) |
|
A Simple VFO for 80 & 160 Meters - This VFO is simple to build and is quite
stable. The VFO produces a two phase output (2 outputs), making it well suited to
supplying a signal to either single ended RF amplifiers, where only one
....(electronic design added 05/06/07) |
|
Add a Signal strength display to an FM Receiver IC - 09/05/02 EDN-Design
Ideas: The Philips (www.semiconductors.philips.com)TDA7000 integrates a monaural
FM-radio receiver from antenna connection to audio output. External
components include one tunable LC circuit for local oscillator, a few
capacitors, two resistors, and a potentiometer to control
variable-capacitance-diode tuning.....(design idea added 3/06) |
|
AN-146: FM Remote Speaker System - National Semiconductor Application Note
(app note added 07/08/09) |
|
AN-543-Monaural FM Transmitter DSP, 20,641 bytes -
AN-543-MonauralFMTransmitter-Analog Device Application Notes (app note added
3/06) |
|
AN-543-Stereo FM Transmitter DSP, 26,085 bytes -
AN-543-StereoFMTransmitter-Analog Device Application Notes (app note added
3/06) |
|
BA1404 HI-FI Stereo FM Transmitter - The above FM transmitter design is a
result of many hours of testing and tweaking. The goal was simple; to test many
existing BA1404 transmitter designs, compare their performance, identify
weaknesses and come up with a new BA1404 transmitter design that improves sound
quality, has very good frequency stability...(circuit added 08/08/08) |
|
BandPass Filter - This bandpass filter is in fact a combined high- and
lowpassfilter. The first stages are a highpass (f>70MHz) and the last stages a low
pass (f<180MHz). The lost of this filter is several watts when driven with
20[Watts], but the output signal is (when adjusted with a spectrum analyser) very
clean.….(electronic schematic added 12/08) |
|
BH1415F FM Stereo PLL Transmitter - Transmitter power amplifier, the output
signal from BH1415F by 2 SC9018, 2SC3355, 2SC2053 amplified signal can reach more
than 500 mW, adjusting well to achieve greater power. Measured by the pull rod
antenna used to be launched in the open 800 meters above. Uses external antenna
will be launched even further. attention in 2053 ....(design added 04/05/06) |
|
BH1417 Stereo PLL FM Transmitter - Frequency is selected with a DIP switch
with 200KHz increments. Transmitter needs a 7.6MHz crystal. (circuit added
8/06) |
|
Bipolar Regenerative
Receiver - Contrary to what some radio experimenters think, a bipolar
regenerative design can be made to work efficiently. The major concern is the low
input impedance of the detector-amplifier bipolar….(electronic design added 08/03) |
|
CB Transmitter - For the regulation it needs a voltmeter (with needle better)
and charge 50W/5W. Connect charge 50W in the place of aerial, with the voltmeter
in the exit voltmeter. Be supplied the transmitter with + 12V. It will be supposed
we have consumption between 0,7-1A. With a screwdriver we regulate the core of
inductor L1/L2 and later the variable C6 until we see the biggest tendency. We
connect the microphone and speaking we observe the clue in the multimeter. If all
have become right will be supposed the tendency, speaking, to go up roughly
30-35%. |
|
Creating a 2nd Headphone Feed When Only One Is Available - (schematic added
03/04/05) |
|
Earwig -FM Transmitter - This is an easy to build FM transmitter that fits
into a matchbox. It transmits to any standard FM radio and can be used around the
home as a baby minder or outdoors for up to 300 metres. Its sensitivity and
clarity are very impressive -even the ticking of a clock can be picked up 3 metres
away. Almost everyone has the ambition to use the airwaves. Whether it be for
remote control or transmitting halfway around the world, we all love to
broadcast. electronic schematic added 05/08) |
|
Easy FM transmitter 0,4 W - (design idea added 08/08/08) |
|
FM Band Monaural Transmitter - (circuit design added 8/03) |
|
FM Band PreAmplifier - (circuit / schematic design added 6/06) |
|
FM Beacon Transmitter 88 108 MHz - This circuit will transmit a continuous
audio tone on the FM broadcast band (88-108 MHz) which could used for remote
control or security purposes. Circuit draws about30 mA from a 6-9 volt battery and
can be received to about100 yards. |
|
FM Booster - (electronic Circuit / Schematic added 10/04) |
|
FM BroADCast Audio Transmitter - (schematic / circuit added 6/07) |
|
FM Bug 1.859.telia - (electronic circuit added 4/05) |
|
FM Bug-transmitter - The circuit consists of two separate stages. The first is
an audio pre-amplifier and the second is a 90MHz oscillator. The first stage is
very simple to explain. It is a self-biasing common-emitter amplifier capable of
amplifying minute signals picked up by the electret microphone....(electronic
circuit added 04/09) |
|
FM CCIR transmitter - (electronic circuit added 6/07) |
|
FM Microphone - A micro-transmitter is so small and sensitive, it have only 8
easy-to-get parts and can be assembled in one hour. (6/03/2006) |
|
FM Microphone 1 - (electronic circuit added 7/03) |
|
FM Oscillator - ASCII format (circuit design added 10/06) |
|
FM Portable - …(schematic added 04/05/06) |
|
FM radio (may be used with PC) Circuit - ….(design added 08/08) |
|
FM Radio Microphone with Internal Loop Antenna (Area 50) - This article began
as a design guide for hyper cranial erogenic field generators, however, your
primitive earth brains are completely unable to respond to erogenic fields in the
100MHz region. I personally had a brain upgrade (for purely medical purposes of
course) so I am able to respond....(schematic / circuit added 4/08) |
|
FM Radio Transmitter (David Sayles) - This small transmitter uses a Hartley
type oscillator. Normally the capacitor in the tank circuit would connect at the
base of the transistor, but at VHF the base emitter capacitance of the transistor
acts as a short circuit, so in effect, it still is. The coil is four turns of
18swg wire wound around a quarter inch former. The aerial tap is about one and a
half turns from the supply end. Audio sensitivity is very good when used with an
ECM type microphone insert. (added 11/05) |
|
FM Radio Transmitters with Opamp - Designed by Kamran Ahmed ….(circuit /
schematic added 5/03) |
|
FM Receiver using MPF106 - (electronic design added 6/07) |
|
FM Remote Speaker System - National Semiconductor Application Note (app
note added 07/08/09) |
|
FM RF Remote Control 88-108 MHz - 1KM Range (added 6/06) |
|
FM Stereo Modulator - (electronic circuit added 10/05) |
|
FM Stereo Transmitter - You'll find that this is a very easy project to build.
It will transmit good quality sound in the FM band ( 88, 108 mhz ). One inportant
item is that the IC chip operates on 3 volts DC. The chip will get destroyed if it
is operated on any voltage higher than 3.5 volts….(added 08/08/08) |
|
FM Synthesizer N°2 - This new FM transmitter is very simple and doesn't need
any RF tuning. First of all ,we have used an integrated VCO: The POS150 from
Mini-circuits. This excellent RF circuit covers all the FM Band in a voltage range
of 4V to 8V. The Kvco factor is very stable all over the FM band, consequently, we
have applied the BF signal directly on the control voltage line coming from the
PLL.....(added 08/08/08) |
|
FM Telephone Bug (Tony van Roon) - (electronic design added 6/07) |
|
FM Telephone line Bug Transmitter (Aaron Cake) - (circuit / schematic design
added 7/03) |
|
FM Transmitter - A simple 2 transistor circuit with a Coil on the
PCB....(electronic schematic added 12/08) |
|
FM Transmitter (2bjttx) - (circuit / schematic design added 6/06) |
|
FM Transmitter (Aaron Cake) - Here is the schematic, PC board pattern, and
parts placement for a low powered FM transmitter. The range of the transmitter
when running at 9V is about 300 feet. Running it from 12V increases the range to
about 400 feet. This transmitter should not be used as a room or telephone
bug....(electronic design added 03/04/05) |
|
FM Transmitter (fmtx_dc) - This simple transmitter operates from a 9V battery
as shown above. I personally built this for a purpose. This is how it
happened:"members of my singing group find it difficult to handle a FM mic in
Church. The choir sings in acapella form and the congregation expect us to perform
well. The old FM mic system was not a perfect solution,....added 6/06) |
|
FM Transmitter (radiockt6) - (electronic circuit added 10/05) |
|
FM Transmitter (techlib) - Here is a new slant on the ubiquitous FM
transmitter circuit. It's an FM sender. It takes a line-level stereo signal, and
puts out a mono FM signal which can be received in another part of the house. It
uses base modulation, which has always worked well in the author's experience,
though spread in base-collector varicap behaviour may conspire to cause
…(electronic design add 6/07) |
|
FM transmitter 0,4 W - (design idea added 08/08/08) |
|
FM Transmitter 1km Range 88-108 MHz - 1KM Range (added 11/05) |
|
FM transmitter 3 W (3W RF part) - With good antenna (dipole placed outdoor and
high) the transmitter has very good coverage range about 1500 meters, the maximal
coverage range is up to 20 km…(added 08/08/08) |
|
FM Transmitter Bug - This small transmitter uses a hartley type oscillator.
Normally the capacitor in the tank circuit would connect at the base of the
transistor, but at VHF the base emitter capacitance of the transistor acts as a
short circuit, so in effect, it still is. The coil ....designed by David Sayles
(electronic design added 6/07) |
|
FM Transmitter Circuit with OPamp - ….(electronic schematic added 03/08) |
|
FM Transmitter for Band 2 VHF - ….(electronic schematic added 03/08) |
|
FM Transmitter With Crystal Referenced PLL Frequency Control Using LMX1601
ATtiny2313, AT90S2313 - An LMX1601 Phase locked loop, a discreet
FET VCO, and an AVR micro controller combine to make a stable, easy to use
monophonic FM transmitter that includes a an audio activated switch that turns the
transmitter on only when its being used…(project added 6/07) |
|
FM Transmitter-2 - ….(circuit design added 03/08) |
|
FM Transmitter-Miniature - (circuit / schematic added 5/03) |
|
FM Voice Transmitter - This miniature transmitter is easy to construct and
it's transmissions can be picked up on any standard FM radio. It has a range
of up to 1/4-mile (Tony van Roon's 400 meters) or more, depending on the
line-of-sight, obstructions by large buildings,etc. It is great for room
monitoring, baby listening, nature research,....(Tony van Roon's electronic design
added 6/07) |
|
FM Wireless Mike - low power frequency modulated transmitter using two
transistors. The circuit works with 9v power supply. . (added 9/04) |
|
FM 88MHz...108MHz Amplifier - (electronic circuit added 6/07) |
|
FM/ AM Regenerative Receiver - Two transistor receiver. (circuit added
08/07/06) |
|
FM3 Mods - (electronic circuit added 7/03) |
|
Ipod Stereo FM transmitter with 1W output power - This project explain how you
can build and connect a powerful 1W amplifier to your FM transmitters…(electronic
design added 03/08) |
|
ISM Transmitter with TDA5100/ TDA5200 - (electronic circuit added 6/07) |
|
Long Range FM Transmitters - (circuit added 8/06) |
|
Low Pass Filter For FM 88-108 MHz - Filter used for eliminate unwanted
harmonic frequency at second and third. Notch filter, Band Pass Filter (BPF), and
High Pass Filter (HPF) sometime combined in constructing LPF design. Schematic
below for FM Broadcast Lowpass Filter 88-108 MHz….(added 08/08/08) |
|
LowPass Filter - The schematic you find here comes from another site on the
internet, but because it's on so many sites, we don't know who actually designed
it. However it's a nice one. Capacitors: C1,C4 22pF cer. C2,C3 51pF cer. Coils:
L1,L2,L3 #18 bus wire, 1/4"diameter, 3 turns * Form the leads from the capacitors
as shown in the little figure below. Then solder them from the pad to the outside
ground area. * Be sure that the turns from the coil are seperated by the same
distance as the diameter of the wire * Form the leads from the coils as shown in
the little figure below. Then solder them in place. * Place the filter in a metal
box, with rf-connectors on both ends ( SO239(=PL259), BNC or
N-connectors)….(design added 12/08) |
