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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. |
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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. |
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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. |
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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. |
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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,..... |
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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)
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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] |
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150mW FM Transmitter - Electroinic circuit design…. [from Harry
Lythall's website] |
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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) |
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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)
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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) |
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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) |
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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) |
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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) |
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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) |
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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) |
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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) |
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2 Transistor FM Transmitter - A compact 2 transistor transmitter for use
at VHF frequencies.… [Andy Collison, designer] |
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2 Transistor FM Transmitters (Bill Bowden) - (electronic Circuit added
03/06) |
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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). |
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25W RF Amplifier - RF amplifier with 25W of power for 88-108MHz FM
transmitters.….(Circuit design added 12/08) |
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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] |
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2W RF Amplifier For 24/23 CM - This page describes TX ATV Transmitter
for 23 cm with output adjustable from 100 to 250mW. |
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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) |
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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) |
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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)
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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) |
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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 - 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] |
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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..... |
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4 Watt FM Transmitter-2 - Schematic and notes |
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40 Meter Direct Conversion Receiver - ..... |
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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] |
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400mW VCO FM transmitter - BF199, BFR91, BFR96, varicap diode BB109.
(circuit added 8/06) |
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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] |
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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. |
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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) |
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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) |
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81 Watt FM stereo transmitter - A high quality broadcast transmitter big
enough for a medium town! [Manfred Mornhinweg] |
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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)
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