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TV Transmitter - A VHF band TV transmitter using negative sound modulation and PAL video modulation. This is suitable for countries using TV systems B and G. __ Designed by Submitted David Kwaku Celestin
TV Video Transmitter - This is a TV transmitter for transmitting video of various video sources such as video cameras, Satellite receivers, DVD players, game consoles, etc. TV transmitter's circuit is working on the 470-580 MHz frequency and can be received on UHF channels 21-34. TV Video transmitter can radiate as far as 300 meters by using a 10-20 cm wire antenna. TV transmitter requires voltage of 9-15 Volts. However, you can also use a 9v batteries. Oscillator is based around BF199 and BFR90 RF transistors. if needed the range of TV transmitter can be extended by replacing BFR90 with 2N3886 transistors.__
TV-VCR Light Source 40Khz Repeater - This circuit is designed to be placed directly in front of a standard TV or VCR remote. The exiting light pulses produced by the circuit match the pulses from the remote but are about 10 times more powerful . . . Hobby Circuit designed by David A. Johnson P.E.-June, 2000
Two key projects - This is a circuit that I particularly like due to its simplicity and speed of construction. With this circuit, it is now possible to include a paddle keyer as an integral part of all, but the smallest, of QRP CW transmitters. it also satisfies my hate for CMOS
! ! __ Designed by Harry Lythall-SM0VPO
Two transistor 40 milliwatt fox transmitter - This two transistor 144 MHz transmitter uses a 48 MHz scanner crystal as an oscillator / tripler. A second transistor boosts the power output to 40 milliwatts. A 7-element filter is used to minimize output on the third harmonic. (I did not want it to be easy to RDF this on the 450 MHz third harmonic) __ Contact Joe Leggio WB2HOL
Two Transistor FM Colpitts Transmitter - 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, __ Designed by Andy Collison
Two transistor FM transmitter & PCB layout - A simple 2 transistor circuit with a Coil on the PCB. __ Designed by G.L. Chemelec
Two transistor FM transmitter / FM bug - VOYAGER is a super-sensitive FM Radio microphone developed by Talking Electronics. The components are all common types of resistors, capacitors and transistors matched so well in this circuit that amazing sensitivity and distance are obtained. The name VOYAGER was given to it "because it goes so far". We have re-designed the Board and further matched some components to suit the needs of the classroom. The result is a superb bug which is compact but powerful, and quite easy to build__ CdS Electronic
Two Transistor Replaces IC - Bi-directional iIC buffer is enhanced to add an enable pin accommodating hot-swappable operation. Replaced LTC4300. __ Designed by Jim Haggerman, Hagerman Technology LLC
Two Transistor replaces IC (Hagtech) - I am always impressed with the way semiconductor manufacturers go out of their way to make the end designer’s job easier. One example is the LTC4300 recently introduced by Linear Technology. __ Designed by Jim Haggerman, Hagerman Technology LLC
Two Valve 40m CW Transmitter - amateur radio construction projects. circuit only, no description given. __ Designed by Peter Parker
Two Valve Transmitter - This transmitter is very stable and will deliver up to seven watts of power. Do not be put-off by valves as they are VERY easy to work with and it seems that there are quite a few valves around. Because no-one wants these obsolete things they may be bought for next to nothing at radio rally's. if you are not too particular what type of valve you want then there are lots of valves available. __ Designed by Harry Lythall-SM0VPO
Two Way Morse Practice Set - The first step to learning Morse is to be able to memorise the sounds of all letters and numbers. This can be accomplished with the help of Morse practice tapes or classes. Once you know all the characters, the WiA Morse practice broadcasts and/or continuous VHF Morse beacons can be used to increase your receiving speed. __ Designed by Peter Parker VK3YE-first appeared in Amateur Radio, April 1998
Two-Meter Transmitter - This project is a simple transmitter using only one crystal and will cover 145.00 to 146.00 MHz. The crystal is a 44.9333 MHz crystal for 145.500 receive, as used in the Trio (Kenwood) 2200, PYE, Motorola, Tait equipment, to name but four. The frequency of the crystal is not critical as almost any other Xtal for the 2-meter band will function __ Designed by Harry Lythall-SM0VPO
Two-Transistor FM Voice Transmitter - 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, __ Designed by Andy Collison
Two-way Morse practice set - The first step to learning Morse is to be able to memorise the sounds of all letters and numbers. This can be accomplished with the help of Morse practice tapes or classes. Once you know all the characters, the WiA Morse practice broadcasts and/or continuous VHF Morse beacons can be used to increase your receiving speed. __ Designed by Peter Parker
TX200 High Quality 200mW FM Transmitter - Here is the latest and greatly improved TX200 VFO/VCO FM transmitter. The most versatile transmitter to date that can be turned into high fidelity stereo PLL based 200mW FM transmitter. it is a perfect circuit for transmitting your music around the house and yard (8/06) __
TX300 300mW FM Transmitter - Here is the latest and greatly improved TX200 VFO/VCO FM transmitter. The most versatile transmitter to date that can be turned into high fidelity stereo PLL based 200mW FM transmitter. it is a perfect circuit for transmitting your music around the house and yard (8/06) __
TX-500 FM Transmitter Project - The TX500 is a simple to build 500mW FM Transmitter. it consists of three blocks; modulator / oscillator, two stage 500mW VHF amplifier and LED based power meter. The TX500 allows to transmit audio signals to FM band at frequencies from 88 MHz to 108 MHz (8/06) __
UHF Remote Mains Switch Transmitter - Designed to control the UHF Remote Mains Switch, this hand-held transmitter can operate over a 200m range. it's based on a PIC micro and a pre-assembled transmitter module, making it easy to build and get going.__ SiliconChip
UHF-TV Preamplifier - Circuit only__
UHF-TV Preamplifier - Circuit only__
Ultrasonic Remote Control and Intruder Detector - This transmitter is designed to work with the next circuit as a remote control transmitter/receiver. it is only a single channel and you could once get multi-channel chips for the whole job. However ultrasonics have fallen out of favour commercially so I think most of these chips are now obsolete. __ Designed by Richard Torrens
Ultrasonic switch transmitter & receiver - The circuit described generates (transmits) ultrasonic sound of frequency between 40 and 50 kHz. As with any other remote control system this cirucit comprises of a minI transmitter and a receiver circuit. Transmitter generates ultrasonic sound and the receiver senses ultrasonic sound from the transmitter and switches on a relay __ Designed by Andy Wilson
Ultrasonic transmitter - This is a fairly commonly published self-oscillating driver for ceramic (piezo) resonators. However with some resonators it can be a bit temperamental: the 1n0 capacitor across the top transistor of the totem-pole helps it to start up. Some resonators won't need this. __ Designed by Richard Torrens
Ultrasonic transmitter & receiver - Presented here are the circuits of ultrasonic transmitter and receiver that use two CD4017 decade counters and ultrasonic transducers. __ Designed by PRADEEP G.
Unidirectional RF wireless transmitting & receiving - Digital in, digital out, with no wires! ! ! Yes, it can be that easy but there are some things you will find out about going wireless that you may not have counted with wired connection. This App Note will guide you through a simple RS232 link and illustrate how easy these devices are to use as long as you know how to handle a couple wireless phenomenon and plan your project to take these into account. __ Contact info @ wzmicro.com
Unusual Frequency Dividers - This paper is a collection of unusual frequency divider techniques which offer features not achieved with ordinary divider ICs or prescalers __ Contact: Charles Wenzel of Wenzel Associates, Inc.
USB 0-500MHz RF Power Meter based on a AD8307 - Measurement of transmitter output RF power has never been easier and more precise. AD8307 USB 0-500MHz RF Power Meter allows to measure the power of transmitters from 1nW to 2W / 50W with 40dB attenuator. Output is displayed in dBm, Watts (nW, uW, mW and W range) as well as input voltage. USB RF Power Meter is based on popular AD8307 watt meter IC and PIC 18F2550 microcontroller. __
USB FM Transmitter - Here is a simple USB FM transmitter that could be used to play audio files from an MP3 player or computer on a standard VHF FM radio by connecting it to an USB port. The circuit use no coils that have to be wound. This USB transmitter can be used to listen to your own music throughout your home. To keep the fm transmitter circuit simple as well as compact, it was decided to use a chip made by Maxim integrated Products, the MAX2606. This IC from the MAX2605-MAX2609 series has been specifically designed for low-noise RF applications with a fixed frequency. The VCO (Voltage Controlled Oscillator) in this IC uses a Colpitts oscillator circuit. The variable-capacitance (varicap) diode and feedback capacitors for the tuning have also been integrated on this chip, so that you only need an external inductor to fix the central oscillator frequency.__
USB FM Transmitter MAX2606 - This MP3 Player FM transmitter can be used to listen to your own music throughout your home. The transmitter circuit use no coils that have to be wound. When this FM transmitter used in the car, there is no need for a separate input to the car stereo to play back the music files from your MP3 player. __
USB Mono FM Transmitter - This small FM transmitter with a range of about 50 meters designed for connection to the USB port. With lots of mini-transmitters then you have a comprehensive, action-packed radio program. Due to the power supply via the USB port of a high frequency stability is achieved. Alternatively, the receiver, a battery 5 to 12 volts to operate.__
USB RDS Coder Board using ATmega32 - This board is a RDS coder using an ATMEL AVR ATmega32. This board can be controled by a RS232 link, USB interface or SPi. TA data is displayed wiyth a LED and can be controled by : - Hardware input - RS232 - USB - SPI (not yet implemented) __
V7 VHF FM Transmitter - The circuit itself is fairly conventional, with a couple of small refinements. it all begins with TR1 (BC547) in an inverted Hartley oscillator configuration. The feedback to the Base of TR1 is via a small 4.7pf capacitor to help keep the oscillations as weak as possible whilst allowing the oscillator to be a reliable starter __ Designed by Harry Lythall-SM0VPO
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