|
THE FOX 750-750 milliwatt transmitter - This three transistor 144 MHz transmitter uses a 48 MHz scanner crystal as an oscillator / tripler. A second transistor boosts the signal to 40 milliwatts, a third amplifies the power output to 750 milliwatts. __ Designed by Joe Leggio WB2HOL
THE FOX-250mw transmitter with timer - The timer consists of a Radio Shack travel alarm. I disconnected the pizeo-ceramic beeper and used the signal to set a flip-flop built from a CMOS
4011. The output of the flip flop is connected to a switching transistor which supplies voltage to the CW iD. I used an R/C combination on the flip/flop so it would be reset when first powered up. A push button is provided so the flip/flop can be set manually (turning on the transmitter) __ Designed by Joe Leggio WB2HOL
THE FOX-40 milliwatt 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) __ Designed by Joe Leggio WB2HOL
THE FOX-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
The GW3UEP 630m Transmitter Part 1 - I've just completed the Muppet-styled printed circuit version of my previously breadboarded GW3UEP 630m transmitter. The earlier version was built "ugly style" in order to optimize part values and measure circuit parameters. __ Designed by VE7SL - Steve
The GW3UEP 630m Transmitter Part 2 - I was finally able to put the finishing touches on the new GW3UEP Class-E transmitter by mounting the hardware on a small 19" panel __ Designed by VE7SL - Steve
The Jet Propulsion Laboratory-"Smart VOX" - For creating a COS signal from a radio that doesn't have one. This circuit was developed to control the retransmission of NASA Select audio over JPL's W6ViO repeaters. __ Designed by Randy Hammock KC6HUR and Jan Tarsala WB6VRN
The Journey to Forever--Crystal Radio - You can make a crystal set out of almost anything -- any small box, or just a bit of wood, or a frisbee or a deodorant dispenser (actual examples) , or these (recommended for beginners) : __ Designed by Keith Addison
The MAS-80 - Designed to be competative in the DL 80M "Mininum Art Session" contest, this rig features a crystal controlled 2W transmitter and a sensitive regenerative receiver, using 51 discrete parts on a 3.5" x 2.5" circuit board. __ Designed by Steven "Melt Solder" Weber KD1JV
The Minimitter FM Stereo Transmitter - Broadcast a stereo signal from your CD player or any other source. The signal can be picked up on a standard FM receiver.__ SiliconChip
The Repeater Builder's Friend - A device to help to you fix your repeater or program your controller __ Designed by Matt Krick K3MK
The Simplest FM Transmitter - This is the most simple and cheap FM transmitter you can ever find. it's powered by CR2025 3V battery and current consumption is very low. The total size of this FM transmitter is less than that of a matchbox. The circuit has a central RF oscillator NPN transistor BF494. A coil takes care of the output frequency. The coil consists of 36SWG wire 2.5 turns in 5mm diameter ferrite rod. Keep the circuit as small as possible. By using a standard TV antenna, the range of this transmitter can go up to 1KM radius, using small 15-20cm wire, it can work up to around 50M range. This circuit is most suitable for miniature FM transmitter for use in computer, mobile etc to send music to home theater system without wires, and in homemade wireless walky-talkies.__
The Simplest FM Transmitter Ever Made - This is the most simple and cheap FM transmitter you can ever find. This circuit is really cool. This runs at very low voltage, by a CR2025 3V battery, current consumption is also low. And the total size of this FM transmitter (including battery, excluding antenna) is less than that of a matchbox. The circuit has a central RF oscillator NPN transistor BF494 (substitute: BF199). A coil takes care of the output frequency. it consists of 36SWG wire 2.5 turns only in 5mm diameter ferrite rod. Keep the circuit as small as possible.__
The TX-300 FM Transmitter Project - This power meter will let you test both the output power of Q2 (VHF amp) and Q1 (oscillator). Circuit is now on the separate board so you can fit the main circuit of the smaller PC board.
__
The TX-500 FM Transmitter Project - This power meter will let you test both the output power of Q2 (VHF amp) and Q1 (oscillator). Circuit is now on the separate board so you can fit the main circuit of the smaller PC board.
The UnFETtered Crystal Radio! - Several weeks ago I became aware, via the internet, of an experimental AM 'crystal set' style of receiver, that uses what is known as a ZVB (Zero Voltage Bias) device. This is in the form of an IC , which contains either a 2 pack or 4 pack of specialised FETs (Field Effect Transistors) that require no bias voltage on their gates to conduct current from source to drain. They simply rely on signal voltages to turn them partially or fully on. This new IC , dubbed the ALD110900A, is made by Advanced Linear Devices __ Designed by Austin Hellier © April 2007
The Wilkinson Power-Combiner On 630m - it's often easier to achieve high power on 630m or LF by combining lower powered amplifiers than it is to build a single high-power rig. A simple Class D push-pull switching FET amplifier can readily produce 400-500W when operated in the 35V range __ Designed by VE7SL - Steve
Three transistor 750 milliwatt fox transmitter - This three transistor 144 MHz transmitter uses a 48 MHz scanner crystal as an oscillator / tripler. A second transistor boosts the signal to 40 milliwatts, a third amplifies the power output to 750 milliwatts. __ Contact Joe Leggio WB2HOL
Three Transistor FM Radio Bug - My FM Wireless Microphone has been a very popular project with beginners and experienced constructors alike. it has been used inside guitars and as the basis of a remote control system. __ Designed by Harry Lythall-SM0VPO
TM-441 9k6 packet Modification - Schematic only __ Designed by Guy Roels ON6MU
T-Match ATU (Antenna Tuning Unit) - A simple T-Match ATU. I used silver plated copper wire for L1 and L2. if you use enamelled copper wire, remove the insulation on one side of the coil, so that you can easily change the number of turns used for each band. if you don't need to cover 160 Metres, L1 can be reduced to about 25 turns. L2 is only used on 10 Metres. __ Designed by EI9GQ homebrew radio
Tracking transmitter - Schematic only, no circuit description __ Designed by Andy Wilson
Transmit Arinc 429 Data - 07/11/02 EDN Design ideas: The ARiNC (Aeronautical Radio inc] 429 specification defines the air transport industry's hardware and protocol standards for the transfer of digital data between avionics systems. Circuitry that can implement elements of the 429 sp Design by Steve Woodward, University of North Carolina, Chapel Hill, NC
Transmitter Accurately Transfers Voltage Input - 15-May-03 EDN Design ideas: When you connect remote sensors to a central process controller, a simple, robust, and commonly used interface is the 4- to 20-mA loop. The advantages of this current loop include the simplicity of just two twisted wires that share both power and signal, the loop's high noise immunity in harsh environments, and the de facto loop standard within the process-control industry Design by Clayton Grantham, National Semiconductor, Tucson, AZ
Transmitter FM 45W with valve - The catering better it does not become at straight line from the network 220V but via transformer 220V/220V of isolation and safety 1AWhen does not exist the R3, the force of expense is bigger, but respectively is increased also the hum 50Hz, because the simplicity of designingThe control (Audio in) can become from a kasseto'fwno or other powerful source. if it is microphone it will be supposed precedes amplifier so that it acquires a force of order of 8W roughly. __ Designed by Kyriakos Kontakos
Transmitter for Line Powered Xenon Flash - This line powered xenon flash circuit drives a small camera type flash tube. it has an optical isolator to allow the flash to be safely triggered from some remote device. A flash rate of 2Hz is possible with the circuit . . . Hobby Circuit designed by David Johnson P.E.-June, 2000
Transmitter for SSB Tranceiver - For the transmit mixer, I used a simple single ended JFET mixer. The FET is a J113. The inductors are TOKO KANK3334. You can wind your own on TOKO, or similar formers PRI = 18T SEC = 3T __ Designed by EI9GQ homebrew radio
Transmitter senses triple relative-humidity figures - 09/26/02 EDN Design ideas: The circuit in Figure 1 is a triple, relative-humidity sensor and radio transmitter. Sensors 1 and 2 form two gated oscillators with natural frequencies of 10 and 5 kHz, respectively, at relative humidity of 50%. The gated oscillators use variable resistances R2 and R3, respectively. Together, these two oscillators generate FSK-modulated outputs at output of IC 1B, Pin 6 Design by Shyam Tiwari, Sensors Technology Ltd, Gwalior, India
Transmitter using LM317 - A few years ago I built one of those projects that never worked, but it did do something unusual. The PSU side of a portable receiver was very unusual in that it GENERATED RF in the HF spectrum. The fault was traced to a couple of errors on the PCB. After a little investigation I used the error to build myself an HF CW QRP transmitter, based upon an LM317T voltage regulator chip! ! ! __ Designed by Harry Lythall-SM0VPO
Transmitter-5 Watt - This is a very simple 5 watt CW TX based upon a TTL logic chip. There is just one "tricky" component and this is Cx. This component should have an impedance of about 10 - 50 ohms at the frequency of interest. if you wish to reduce the transmitter power, increase the value of Cx. it is Cx which causes the square wave from the output transistor to approximate a sine waveform. The value of Cx is the price of simplicity in this TX __ Designed by Harry Lythall-SM0VPO
Transmitters 27 & 303MHz - in this discussion we cover 27MHz transmitters and receivers as found in remote control cars, aeroplanes, walkie talkies and some of the older-style garage door openers. We have provided a number of circuits so you can work out the best type for your application and these circuits will also help you understand which components are critical __ Designed by Collin Mitchell
Travel Alarm used to control 250 milliwatt transmitter. - The timer consists of a Radio Shack travel alarm. I disconnected the pizeo-ceramic beeper and used the signal to set a flip-flop built from a CMOS
4011. The output of the flip flop is connected to a switching transistor which supplies voltage to the CW iD. I used an R/C combination on the flip/flop so it would be reset when first powered up. A push button is provided so the flip/flop can be set manually (turning on the transmitter) __ Contact Joe Leggio WB2HOL
|
