RF Transmitter Circuits
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This circuit is a powerful video sender in VHF band. The modulator section is designed to operate on either channels 7 to 13 or 14 to 29. For channels 7 to 13, L1 and L2 are 3 turns of #22 wire wound on a 3/16 inch form. For channels 14 to 29, L1 and L2 are.... -
The circuit presented here is a simple audio/video transmitter with a range of 3 to 5 metres. The A/V signal source for the circuit may be a VCR, a satellite receiver or a video game etc. A mixer which also operates as an oscillator at VHF (H) channel 5 TV.... -
The RF oscillator using the inverter N2 and 10.7Mhz ceramic filter is driving the parallel combination of N4 to N6 through N3.Since these inverters are in parallel the output impedance will be low so that it can directly drive an aerial of 1/4th wavelength..... -
This circuit is a simple two transistor (2N2222) FM transmitter. No license is required for this transmitter according to FCC regulations regarding wireless microphones. If powered by a 9 volt battery and used with an antenna no longer than 12 inches, the.... -
The circuit is an VXO with buffered output. It operates on 20-meter amateur radio band with the output voltage about 0.2 Vp-p. The crystal frequency is pulled by tuning the variable capacitor CV1 about 36Khz with only one crystal (Y1), and 250Khz by using.... -
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.... -
This circuit generates a low power test signal and should not be used as a transmitter. Make sure you are within the law in the locality in which you operate this. As this was built from parts laying on the bench, it isn't optimized, but it does demonstrate.... -
This circuit uses a small microphone to capture the sound and some transistors to generate radio waves that can be picked up by a FM receiver like a car stereo. The first part is the microphone and some resistors to get it working. Next we have a capacitor.... -
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 so that the music can be transmitted at the same audio level, stereo encoder for stereo transmission, low pass.... -
This project arises from the need to home-build a valid tuning control for a multi band transceiver. It consists of a partial syntesis V.F.O. that fits to single conversion equipments with an I.F. stage nearby 9 MHz. The circuit can cover the whole H.F..... -
The main box of the Transmit Selector system is designed to be located in the technical rack of a small radio broadcast station. There are four stereo balanced line inputs, either of which can be routed to a stereo balanced output. The signal routing is.... -
This document describes the transmitter system supplied to Radio Glen for testing as designed and constructed by Henry. The transmitter is supplied in prototype form and has the physical limitations of an instrument constructed using prototyping.... -
The GHF1 is a small generator covering the HF and LF band from 30 Hz to 30 MHz in 6 ranges. The sinusoidal signal obtained can be amplitude modulated (AM) or frequency (FM). The GHF1 also has a sweep function. An LCD display 2 x 16 characters allows the.... -
This new FM transmitter is very easy to make 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.... -
This one-valve (ECL82) CW Transmitter occupies a very special place in my amateur radio history. I was first licensed in 1994 but did not operate on air. I committed to only ever operate equipment which I had made myself. I had no time for radio construction.... -
This circuitry offers some features that are highly desirable when building a QRP (or ANY) transceiver. It also includes a combination of features that many might not always take the time to include in their projects. Considerable effort has been made to.... -
This transmitters' intended purpose is for morse-code only in the 30 meter band (10Mhz). It is a low-power QRP type and needs to be connected to your existing tranceiver. The harmonic rejections on the prototype were measured at 40dB on 20Mhz and 50dB on.... -
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,.... -
The original TX was designed to be only PULSE Modulated for a proportional R/C system, but I later used the same circuit to make an HF bands Amplitude Modulation (AM) transmitter using PA-Base Modulation. It eliminated the need for a modulation transformer;.... -
Here is a simple little HF TX. It may be modified for all the HF bands, but the details given are only for the 7MHz band. The basic transmitter uses two transistors; BC547 (as usual) and will deliver over 250mW of power. CW keying may be achieved by.... -
The circuit for a powerful AM transmitter using ceramic resonator/filter of 3.587 MHz is presented here. Resonators/filters of other frequencies such as 5.5 MHz, 7 MHz and 10.7 MHz may also be used. Use of different frequency filters/resonators will involve.... -
In this circuit, a 74HC14 hex Schmitt trigger inverter is used as a square wave oscillator to drive a small signal transistor in a class C amplifier configuration. The oscillator frequency can be either fixed by a crystal or made adjustable (VFO) with a.... -
Here is my Sputnik QSO Party transmitter prototype. The RF output power is 450mW with 70Vdc @ 14. 4mA on the V2 anode. The V2 screen (G2) current is 1. 6mA. The V1 anode current is 1. 05mA with 45Vdc @ 176uA at the screen (G2). These little vacuum tubes.... -
The FM transmitter is relatively simple to build and with only one adjustment it is ideal for the absolute beginner. But before I continue, let me just make one thing clear. With Wide-Band deviation, the VCO is never locked in phase, only in frequency. It.... -
User Agrement & Disclaimer Disclaimer All files are found using legitimate search engine techniques. This site does not and will not condone hacking into sites to create the links it list. We will and do assume that all links found on the search engines we.... -
The circuit diagram of Radio Collar Transmitter has been described here. This circuit is based on the IC NE 555 which is the central part... -
This project provides the schematic and the parts list needed to construct a 3V FM Transmitter. This FM transmitter is about the simplest and most basic transmitter to build and have a useful transmitting range. It is surprisingly powerful despite its small.... -
circuit diagram of a modulator circuit in a transmitter and receiver of a amplitude modulation...
New Circuits
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This project fits more for custom made battery casing that can have more space to hide things inside. This switch with few alterations can be used for any other project as well but is designed based on e-bike needs! This project use a clever functionality of.... -
The circuit described here uses ultrasonic oscillations and operates based on the propagation velocity of these oscillations in the air. Thus, we can easily determine the distance of two points if the time within which the wave travels this distance is.... -
Sometimes the precious metals are hidden too deep and are not detected except with complicated devices. In many cases, however, small pieces of precious metal buried near the surface can be detected by relatively simple means. Everyone is very attractive to.... -
Many times for various reasons we forget or can not water the plants that we have in our homes. And many humidity sensors units just notify us with a beeping sound or with a flashing light, that the pot needs watering. But what if we are away from home? This.... -
The principle behind a metal detector is really very simple. Proof of this is the circuit that follows, in which it proves that the construction of a metal detector can be done in the minute, with few components that we find very easily everywhere. With the.... -
The sub-harmonic bass generator is a sound producing unit for guitars. The sound it produces looks very much like that of the bass guitar. The octave generator is sometimes quite unusual since it does not produce any of the usual ways of coloring the sound,.... -
In the past the sounding (sea bottom measurement) was done with the "bullet", that is, with a heavy lead object that the seamen plucked into the sea hung from a calibrated rope. As soon as the "bullet" reached the bottom, the depth appeared directly from the.... -
This Amplifier was designed to have the following specifications: Distortion less than 0.1% at full power of 100W even at 20KHz. Power has to be attributed to an extended bandwidth. The output transistors must be protected against short circuits. The power.... -
A series of LEDs serve to alert the gardener when plants need water. Using two conventional digital integrated LEDs and a series of LEDs, we make a very useful device for gardening. The device detects the amount of water in the pot and alerts the grower.....
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