|
|
|
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, I find that I can get 10 to
20 meters away..... |
|
10.7MHz FM Detector - Many times I have been experimenting with QRP and VHF
FM and needed a very simple FM detector. Detecting FM requires an amplifying limitor
stage as well as coils and diodes. Many IF chips have a built-in detector but these
cost a couple of 'bucks/quid/spän', yet still require a bit of setting up. FMIF-DET is
based upon a SN7401 quad NAND gate with open collector outputs and perform the same
function. The 1K0 pot controls the centre frequency and the 'see text' resistor is
selected for the PLL lock range, depending upon..... [Design by Harry Lythall -
SM0VPO] |
|
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 - (circuit / schematic design added 6/06) |
|
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) |
|
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) |
|
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 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) |
|
2 Transistor FM Transmitter (Rob van der Weijden) - A compact 2 transistor
transmitter for use at VHF frequencies.....(design added 8/03) |
|
2 Transistor LED Flasher (Bill Bowden) - This circuit will flash a bright
LED (500 mcd) as an attention getting device or fack car alarm. Component values
are not cirtical and other transistors may be….....(circuit / schematic design added
6/06) |
|
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. |
|
27 MHz FM Receiver - The FMR-201 is a crystal controlled single channel
receiver, comprising of receiving, decoding and open collector output
sections….(circuit added 08/07/06) |
|
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] |
| 2-transistor FM Transmitter
- 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 6/06) |
|
2W RF Amplifier For 24/23 CM - This page describes TX ATV Transmitter for 23
cm with output adjustable from 100 to 250mW. |
|
303 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 FM Receiver - This is a pocket sized receiver I built in 1994.
The idea was to make a simple but useable receiver running off 3V. My previous 6
transistor receiver was more bulky, requiring 12V. This meant 10 x AA cells. I
designed and made a PCB,..(circuit added 08/07/06) |
|
400mW VCO FM transmitter - With good antenna (dipole placed outdoor and
high) the transmitter has very good coverage range about 500 meters, the maximal
coverage range is up to 4 km. .... |
|
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 FM Transmitter with Antenna 88-108 MHz - Two stages -- AUDIO
AMPLIFIER AND OSCILLATOR and RF POWER AMPLIFIER (electronic schematic / circuit
added 11/05) |
|
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.....(schematic 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) |
|
70-120MHz FM Receiver - This simple one chip FM receiver / TV tuner will
allow you to receive frequencies from 70 up to 120MHz. With this small receiver it is
possible to pickup TV stations, entire 88, 108MHz FM band, aircraft conversation and
many other private transmissions.....(added 05/06/07) |
|
80 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. |
|
98-108MHz FM audio transmitter - ….(electronic schematic added 04/09) [Peter
Jakab, Electrical Engineer, Engineer of Informatics] |
|
A Simple FM Stereo Transmitter - (circuit added 6/07) |
|
A small FM transmitter (SMD) - (electronic design added 6/07) |
|
Add a signal-strength display to an FM receiver IC - 5-Sep-02 Issue of EDN
The Philips (www.semiconductors.philips.com] TDA7000 integrates a monaural FM-radio
receiver from the antenna connection to the audio output. External components include
one tunable LC circuit for the local oscillator, a few capacitors, two resistors, and
a potentiometer to control the variable-capacitance-diode tuning..... [Design Idea by
José Miguel-López, RF Center Ltd, Barcelona, Spain] |
|
ALTOIDS Tin Part 15 Version FM Transmitter - The transmitter uses 2 MPSH10
(equiv BF494 or NTE229) transistors in a double-ended free-running voltage controlled
oscillator (VCO) operating at half the output frequency on each side and combined at
L2, which is tuned to the 2nd harmonic of the VCO and covers the 88-108 MHz range. A
standard 9 volt battery is used for power and fits inside the tin. The mono audio
input circuit is totally passive with 70us pre-emphasis provided and the audio quality
is great. |
|
AM FM Simultaneous Transmitter Using Digital IC - (electronic design idea
added 09/08) |
|
Am/Fm/SW Active Antenna - This circuit shows an active antenna that can be
used for AM, FM, and shortwave SW. On shortwave band this active antenna is
comparable to a20 to30 foot wire antenna. This circuit uses receivers that use
untuned wire antennas, such as inexpensive units and car radios.....(added 6/06)
|
|
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]
|
|
AN-543-Stereo FM Transmitter DSP, 26,085 bytes -
AN-543-StereoFMTransmitter-Analog Device Application Notes.....[App Note]
|
|
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, maximizes transmitter's range, and is fairly simple for
everyone to build. We are happy to announce that this goal and expectations have been
met and even exceeded. |
|
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.
|
|
BH1415F FM Stereo PLL Transmitter - This is FM PLL Stereo based BH1415F IC
from Rohm, it's has built in PLL and Stereo Encoder. You can download the schematic,
pcb layout and Hex code. The transmitter menu display with LCD, and this have step
100Khz, 200Khz,.....1000Khz and have Mode menu (stereo/mono). In Action, LCD Display
can solder directly on the bottom. |
|
BH1417 PLL Stereo Transmitter - This is the latest BH1417 FM Transmitter
design from RHOM that includes a lot of features in one small package. It comes with
pre-emphasis, limiter, stereo encoder, low pass filter, PLL rock solid frequency
transmission and RF output buffer. |
|
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%.
|
|
Cheap Crystal filter - Ladder filter using six 4.43MHz Crystals. Building
cheap side band filter for your bome brew SSB Rig. |
|
Ck-3V FM Transmitter - Circuit design (added 02/05) |
|
Coilless FM transmitter! - .... |
|
Count-down timer - Scroll down to find link to circuit drawing and circuit
explanation….(design added 06/09) |
|
Easy FM Keyer - Many no code Technician class amateurs who are struggling to
learn 5 WPM code simply do not have any avenue to get the necessary on the air
practice. Figure 1 is a simple circuit which will generate a 700 Hz tone into any FM
transceiver allowing an amateur to practice CW with another amateur on a 2 meter
simplex frequency..... [Radio Amateur Society of Norwich] |
|
|
