Owner: RF Circuits URL:http://rfcircuits.blogspot.com/ Join Date: Fri, 06 Jun 2008 08:19:52 -0500 Rating:0 Site Description: Electronic Circuits related radio frequency that is special for RF Hobbies all over the world Site statistics:Click here
VHF Audio Video Transmitter 2008-05-19 17:48:22 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 frequency is amplitude modulated by video signal and mixed with frequency modulation, contains video carrier frequency of 175.25 Mhz and audio Read more:Audio
, Transmitter
1W RF Power Amplifier For FM 2008-05-19 17:42:56 This RF Power 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 power amplifier 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 15Vol Read more:Power Amplifier
Video to RF Modulator 2008-05-19 17:41:48 This circuit is a RF modulator which can be used for modulating of video signals. The P1 controls the Light and the P2 controls the contrast of video signal. The RF modulated output signal can be received on the VHF band ( about 189 MHz ). Note that the circuit don't modulate the audio signal of the pictures.
LC Meter 2008-05-19 17:38:26 This is one of the most accurate and simplest LC inductance / capacitance Meter
s that one can find, yet one that you can easily build yourself. This LC Meter allows to measure incredibly small inductances starting from 10nH to 1000nH, 1uH to 1000uH, 1mH to 100mH and capacitance from 0.1pF up to 900nF. LC Meter's circuit uses an auto ranging system so that way you do not need to spend time selectin
HI - FI Stereo FM Transmitter 2008-05-19 17:22:44 Whether you want to create your own radio station, transmit the music around the house, or simply create a wireless link between your iPod and a receiver in your car, this transmitter will let you do these things easily. With BA1404 HI-FI Stereo
transmitter you will be able to transmit MP3 music from your iPod, computer, discman, walkman, TV/SAT receiver, and many other audio sources.The above FM Read more:Transmitter
FM Transmitter From David Sayles 2008-05-19 06:59:50 A small FM voice transmitter for Band 2 VHF. This fm transmitter circuit is simple, output frequency tuned by regulating on coil (L) that parallel with 15pf capacitor. Supply voltage needed for operate this circuit is 9 volt.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 capa Read more:Transmitter
, David
FM Transmitter Circuit 2008-05-19 06:50:17 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 transmitter will be within the FCC limits.The microphone is amplified by Q1. Q2, C5, and L1 form an oscillator that operates in the 80 to 130 MH Read more:Transmitter
, Circuit
Audio/Video Modulator 2008-05-16 14:12:39 if you want to connect a video signal originating from a camera or other video source to a normal TV set,you will need Audio
Video Modulator.The audio and video signal is converted into a UHF TV signal so that the signal can be received through the TV antenna input. In certain countries,it is legal to use this modulator as a mini transmitter by connecting a small antenna.This makes it possible to
Adjustable Band Pass Filter 2008-05-16 14:10:24 The schematic you find here comes from an old Dutch magazine called Free Radio Magazine and is designed by VEROBB-DX. The filter is build symmetrical and has both IN- and OUPUT impedance of 50 Ohm. So it can be used after each buffer-, driver- or amplifier-stage.The dimensions of the coils' diameter is the INNER-diameter of the coils!!! Make sure that the coil's end-wire is in a axial line with th Read more:Filter
Audio/ Video Distribution Amplifier 2008-05-16 13:46:25 Audio Video Distribution amplifierWith the amount of equipment in home entertainment centers today the need to be able to vary the gain of the audio or video signal is needed.I found this particular circuit helpful when used in conjunction with the Universal Descrambler and a Stabilizer circuit I built for making copies of video tapes. It not only allowed me the ability to fine tune the video stre Read more:Audio
, Amplifier
Ipod Stereo FM transmitter With 1W Power Amplifier 2008-05-16 08:06:47 Today it is very popular to connect the Ipod, MP3 or CD player to some kind of FM transmitter. The transmitting signal can the be picked up by any FM radio receiver. Most often used in cars. The problem with most FM transmitter is that they have very weak signal and short transmitting range.Hardware and schematic - LinkThe schematic show you a RF amplifier with very high gain. The feeding RF signa Read more:Amplifier
, Power Amplifier
, Stereo
A Small FM Transmitter With Loop Antenna 2008-05-16 08:05:35 This small Low Power FM transmitter with Onboard Magnetic Loop Antenna
that designed by Radio Morningstar. It's suitable for home fm broadcasting. As seen on YouTube Page.This is the PCB board layout for a small LPFM transmitter that i'l showed on Youtube. This new design is even more powerfull, using 4 instead of 2 transistors. The range will go up to 2 kilometers or even 4 - 7 km using een exter Read more:Transmitter
, Small
Privacy Policy 2008-05-16 07:02:49 Privacy Policy
for RFCircuitsIf you require any more information or have any questions about our privacy policy, please feel free to contact us by email at rfcircuits@telkom.net.At RFCircuits, the privacy of our visitors is of extreme importance to us. This privacy policy document outlines the types of personal information is received and collected by RFCircuits and how it is used.Log FilesLike ma Read more:Privacy
, Privacy Policy
NRG PLL FM Exciter 4W 2008-07-12 07:15:25 This transmitter circuit is the NRG PLL PRO 3, now recognised as the leader in high power pll transmitter kits. Incorporating unique NRG circuit design, it delivers a stunning 4 watts of RF power to a correctly matched antenna. The output power is selectable from 1 watt to 4 watts via an on-board jumper switch. The PLL PRO 3 design uses wide-band power amplifier technology, this eliminates the nee Read more:Exciter
FM Stereo Encoder NJM2035 2008-07-09 12:47:51 This stereo encoder is the perfect solution for those looking for a high quality stereo sound transmission at a low cost. This stereo encoder produces an excellent crystal clear stereo sound and very good channel separation that can match with many more expensive stereo encoders that are available on the market. It is all possible thanks to a 38KHz quartz crystal that controls the 19kHz pilot tone Read more:Stereo
, Encoder
FM Stereo Encoder BA1404 2008-07-09 12:39:42 This FM stereo encoder uses IC BA1404 for transmiting on FM band broadcast. Sub carrier frequency generated from 38 KHz Crystal. FM Power output is around 250mW. For input preamplifier used a couple of IC 741. You need a fm amplifier for boosting rf signal.The Schematic circuitBA1404 datasheetAnother Circuit Read more:Stereo
, Encoder
C-Quam AM Stereo Decoder MC13028 2008-07-18 08:51:52 This electronic circuit is AM stereo encoder that accepts the signal from the IF of a receiver (450 or 455 KHz) and decodes stereo medium wave broadcasts. It operates at 8-15VDC and provides standard level left and right audio output for direct connection to the audio amplifier.
It may be used to support 30Hz-15KHz audio but it depends on the bandwidth of the receiver's IF.
Circuit Schematic
Read more:Stereo
, Decoder
5 MHz Bandwith Video Signal Amplifier 2008-07-18 00:55:20 This video signal amplifier circuit is a broad band amplifier which will take the video signals from your VCR and will amplify them sufficiently to drive up to 3 monitors, TV sets (provided that they can accept direct video signals), or other VCR’s for recording from one video to up to three others. It will also make possible to record from one video to two others and at the same time have a mon Read more:Amplifier
50W Linear FM Amplifier with BLY90 2008-07-18 00:29:11 This RF FM Amplifier
is always essential for the amateur that wants it strengthens some small transmitter. The present circuit of BLY90 can give 50-60W power out with input control 15-20W in FM band II 88-108 MHz.
Schematic Circuit
Printed Circuit Board
Parts List
C1-C4 = 10-80pF
C5 = 10nF
C6 = 1000pF
C7 = 100nF
C8 = 2200mF/35V
TR1 = BLY90
L1 = 1 Turn of diameter of 10mms, 1mm
L2 Read more:Linear
FM Stereo Encoder With RC4200 Multiplexer IC 2008-08-07 02:13:56 This circuit is stereo encoder for stereo modulation fm broadcast. The Basic component for stereo multiplexing is a single RC4200 IC. The textbook way of processing and encoding a stereo signal for FM transmission goes like this:
1) Take both channels and low-pass-filter them at 15kHz, with steep rolloff;
2) Apply pre-emphasis. Depending on the part of the world, it should have either a 75µs or Read more:Stereo
, Encoder
RF Low Pass Filter 1.8-145 MHz 2008-09-16 11:49:18 This lowpass filter circuit is a very basic filter. It required to remove the harmonic frequency content of the transmitter and can be used on frequency 1.8 - 145 MHz.
The cut off frequency of the filter can be achieved by making C2 and C4 variable trimmer acurate filtering. All coils are 22 SWG wound on 10mm Air former spaced at 2mm.
For making coils of the lowpass filter, download this RF Cal Read more:Filter
Yagi Antenna 88-108 MHz 2008-08-30 01:42:05 This antenna below is a construction of an Yagi antenna calculated for the FM broadcasting band 88 - 108 MHz. The central frequency used for 100MHz. You can extrapolate easily below for others frequency grace to values of diagrams. This antenna is less difficult to construct than the one presented on the previous page.
Description
The goal of this page is to help you to construct an antenna, Read more:Antenna
FM Transmitter 2N2218 2008-09-28 21:36:09 Here's simple FM transmitter circuit using transistor 2N2218. Micropohone is a microphone of electret of two terminals and the antenna should possess from 15 to 40 cm.
Below is schematic circuit of the fm transmitter
Printed Circuit Board (PCB) and Component Layout of the fm tranmitter
Parts List of the fm transmitter
Resistors
R1 = 2,2 kΩ
R2 = 4,7kΩ
R3=5,6kΩ
R4 = 47Ω
Ceramic Capacito Read more:Transmitter
40-900 MHz Signal Amplifier-Booster 2008-09-27 23:59:26 This is a small amplifier of signal that cover the frequencies from 40 to 900 MHz. Those frequencies include TV in VHF and UHF and also radio in the frequencies of 88 - 108 MHz, strip of FM. The signals in up to 20 dB, becoming possible to receive even the weakest signals. Below the circuit diagram
The circuit is built in turn of an UHF broadband transistor, BFR 90. This transistor can ope Read more:Amplifier
, Booster
FM Transmitter With BF494 2008-09-27 23:33:23 This is a small circuit fm transmitter using transistor BF494 . The reach of the transmitter will depend a lot on this antenna, of the feeding of the circuit and of the place where will happen your operation.
With a feeding of 6 V (4 piles AA) and an antenna of about 40 cm of length, we can arrive to the 200 meters. With a smaller antenna, or in place with many structures of iron (flagstones) the Read more:Transmitter
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