VHF Circuits
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This VHF VCO circuit is suitable for 30 to 200 MHz. Q1 can be replaced by a 2N3563 for operation above 100 MHz.. -
The range of this transmitter is about 50 feet with a short whip antenna. The tone generator, is made up of a unijunction transistor, Q1, and R1, R2, R3, and C2. Transistor Q1 pulses on and off at a rate determined by the time constant of R1 and R2,.... -
A typical circuit at 20 MHz is shown. The crystal, which has an internal series resistance Rs of 14ohm, oscillates at its third harmonic. The diode clamp Dl and D2 provides a constant amplitude control. .. -
The MAR-x preamp shown will cover up to 1.5 or 2 GHz with the correct MAR-x IC. ATTN1 should be omitted for low noise-figure.appli cations. ATTN1 and ATTN2 provide a means of limiting possible termination range,.. -
The Jammer is a very small circuit and can fit inside a small plastic box with 9V battery inside. It can be very illegal if you attach an external antenna so don't. adjust frequency by turning trimmer. It is intended only as a practical joke device. The.... -
The picture shows the JFET VHF band of super-regenerative receiver circuit, where high discharge tube V1, V2 for the super-regenerative detector tube, IC1 is a low frequency amplifier. Circuit and sensitivity than 1uV, static power consumption less than 10uA... -
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.... -
This is the diagram of VHF RF Preamp circuit 100-175 MHz with single chip MAX2633. The circuit can be used for the entire VHF broadcast and PMR band (100-175 MHz) which can be easily construct without any special test equipment. The grounded-gate.... -
Developed as interface between General Instruments AY-3-8500-1 TV game chip and antenna terminal of TV set. Adjust C1 to frequency of unused channel to which receiver is set for playing games. Article gives all circuits but covers construction only in.... -
This circuit uses an oscillator (2N2222) and a diode Dl as a nonlinear mixer. The frequency is set by a slug in Ll. RFCl, Cl, and RFC2 form a low-pass filter to pass video and block rffrom the video source.. -
The preamplifier offers 20dB in all the region of VHF and it still can reach also their 500MHZ. The amplifier is a circuit of high frequency RF with distinguishable materials. The amplifier as circuit strengthens the tendency of signal with concrete aid,.... -
This application note describes a low cost, high performance UHF short-range Radio ASK receiver design using the Microchip Technology rfRXD0420. The reference design is suitable for: Wireless remote command and control Remote Keyless Entry (RKE) Security.... -
The 30 watt amplifier schematic shown below provides an appropriate power boost with an input of 4 watt up to 6 watts. The circuit is designed to cover 88-108MHz FM Broadcast Band. However, the circuit is very stable at my place and provides a clean-output.... -
Below 10 MHz, the realization of engineering models is fairly straightforward and not critically dependent on pc-board layout. At VHF, parasitic circuit elements and spurious coupling can wreak havoc with attempts to achieve performance at low cost without.... -
Another version of the 1W VHF amplifier for the FM transceiver, well, in fact, it`s still the same version since I didn`t managed to get 1W. YET! Today I made some tests with a 2n2553 and a 2n2866. it melted solder in one of the base resistors (never I had.... -
To be independent of the local radio stations for testing VHF receivers, you need a frequency-modulated oscillator that covers the range of 89. 5 to 108 MHz ” but building such an oscillator using discrete components is not that easy. Maxim now has available.... -
This small transmitter uses a hartley type oscillator. Normally the capacitor in the tank circuit would connect at the base of the transistor, but at VHF the base emitter capacitance of the transistor acts as a short circuit, so in effect, it still is. The.... -
This page contains material related to the technical issues on taking meteor counts thus monitoring the meteor influx using VHF radio receivers. It is not meant to be a comprehensive how-to guide, but tries to fill some gaps and give second opinions on.... -
In contrast to traditional small-signal approaches, the use of large-signal, time-domain design techniques helps deliver low-noise grounded-base oscillators for VHF/UHF applications.... -
One of the most useful gadgets a video enthusiast can have is a low-power VHF TV Transmitter. Such a device can transmit a signal from a VCR to any TV in a home or backyard. Imagine the convenience of being able to sit by the pool watching your favorite.... -
Here`s a design circuit for very simple low cost and ultra compact VHF UHF Low-Noise amplifiers circuit can be designed using the MAX2664 and MAX2665 ultra-compact LNAs for VHF/UHF applications. These devices incorporate a broadband LNA with an integrated.... -
A very simple and efficiency active antenna electronic project can be designed using this electronic schematic circuit that is based on transistors. This active antenna electronic project is useful for a wide range of RF frequencies covering three RF bands.... -
We all know how a dip meter works and what it measures - the resonance of an LC circuit. The circuit featured here is designed to work in the VHF range. The tester coil is inserted in the LX terminals and placed near the LC circuit to be tested. The variable.... -
You can cut away the 555 timer oscillator part and add your favorite microphone modulating circuit to transmit voice over to your tv set with a little tuning. Schematics in Schematics Depot were found on the internet and assumed to be in public domain.....
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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