Basic FM Transmitter - This basic RF oscillator circuit is easy to build and the components are not critical. Most of them can be found in your junk parts box. The circuit operated with 9V DC power supply. The L1 antenna coil can be made by close winding 8 to 10 turns of 22 gauge insulted magnetic wire around 1/4 inch form such as a pencil. You can experiment with the size of the coil and the number of turns to see how it affects the frequency and signal output of the oscillator. You should be able to pick up its signal with standard FM radio receiver. Signal in to any audio player through 0.1uF capacitor.__
Basic RF Oscillator #1 - This circuit switches a relay at dark via a Light Dependent Resistor or LDR for short. The applications are numerous. in my application, it switches on a light with an older type movement sensor and is mounted on the top corner of my workshop with the LDR facing upwards. The Dark Activated Relay prevents that the light is triggered during daylight hours. But, it can also be used to switch led-beacon lights for your driveway, or whatever __ Designed by Tony van Roon VA3AVR
Basic Stamp 1 & 2 Repeater Controller construction projects - Cheap controllers __ Designed by Roger Cameron NØYOX.
Basic VOX - A recent look at some of the budget priced HF transceivers revealed that they were missing a VOX. Although most of these budget priced transceivers performed admirably, it would certainly be nice to have VOX capability. Figure 1 is a basic VOX circuit which will perform very well once the VOX level is set correctly. This circuit is low cost and all parts can be found at your local Radio Shack store __ Designed by Radio Amateur Society of Norwich
Battery operated FM reBroadcast transmitter - This implementation is adapted to rebroadcast the output of a CD player, television receiver, or radio receiver. I use it so that I can move about the house and listen to my favorite programs without disturbing others. Within and the house, I find that I can get 10 to 20 meters away __ Designed by Dick Cappels
Beeper bug transmitter for fox hunt & vehicle tracking - This bug can be attached to anything from a glider to a plant and you can track it with a radio. Why track a plant? The Beeper is the result of many requests for a minI tracking device and introduces a new world of tracking __ Designed by Collin Mitchell
BH1415F FM Stereo PLL Transmitter - Transmitter power amplifier, the output signal from BH1415F by 2 SC9018, 2SC3355, 2SC2053 amplified signal can reach more than 500 mW, adjusting well to achieve greater power. Measured by the pull rod antenna used to be launched in the open 800 meters above. Uses external antenna will be launched even further. attention in 2053 need to be installed and tested at the load connected to leave, or else very easily burn 2053, 50 European amateur production of 2 W can be used instead of resistance. installed and tested at three levels circuit can be installed and tested.__
BH1417 PLL Stereo Transmitter - 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, stereo encoder, low pass filter, PLL rock solid frequency transmission and RF output buffer.__
BH1417 Stereo PLL FM Transmitter - The new FM Stereo Micromitter is now crystal-locked which means that the unit does not drift off frequency over time. in addition, the distortion, stereo separation, signal-to-noise ratio and stereo locking are much improved on this new unit compared to the earlier designs. The specifications panel has further details__ SiliconChip
BH1417 USB FM Transmitter - Here's BH1417 USB FM Transmitter with built-in PLL circuit. its low-frequency signal is converted into high-frequency, which can take any audio device with FM radio (stereo, car CD, MP3, DVD player, etc.) , as a normal radio station. Transmitter power is sufficient for reliable reception of its signal within a few tens of meters. The basis of the device is a chip BH1417F, included in a typical scheme. This device contains all the necessary circuitry to generate a composite stereo signal c of the pilot tone, the RF generator with PLL and power amplifier. A detailed description is given in.__
Bipolar Regenerative Receiver - Contrary to what some radio experimenters think, a bipolar regenerative design can be made to work efficiently. The major concern is the low input impedance of the detector-amplifier bipolar. __ Designed by Ramon Vargas
Bob Sickel's Antenna Switch for Dicke Switching Receivers - This is a Radio Astronomy Project __ Designed by Radio-Sky Publishing
Build a 100Khz Crystal Calibrator - There is a great deal of old amateur gear which many amateurs have decided to restore and bring back to life. While much of the early amateur transceivers work just fine they usually lack a digital readout and must rely on analog dials for tuning. The problem of dial calibration is complicated by the non-linear effects of tuning capacitors. This month's circuit is a 100Khz crystal calibrator using an inexpensive microprocessor crystal and CMOS
IC 's which are readily available at Radio Shack. __ Designed by N1HFX
Build a Two Channel Signal to Noise Voter - As hand-held transceivers (H-Ts) become smaller, and low power, battery conserving operation becomes more popular, the disparity between the transmitting range of a typical 100 watt repeater compared to the repeater accessing range of a typical 1 watt or less H-T becomes more and more apparent. How often have you found it difficult (or impossible) to access a repeater with a low power H-T even though you can hear the repeater at full quieting? This can happen even if the repeater is equipped with a high sensitivity, state-of-the-art receiver. __ Designed by Mark Kolber WB2WHC
Build this Simple Circuit A/V wireless transmitter - This circuit provides you with wireless audio and visual transmission to a TV. The TV acts as a receiver, eliminating the need to buy a separate monitor. You can also hook it up to a VCR or CCD Camera, and even set up a remote CCTV security system! Circuit design __ Contact info @ wzmicro.com
Build Your Own Micro FM Transmitter - A fun Make project. __ Contact Jameco Electronics
Build Youself a Service Monitor? - For creating a COS signal on radios that don't have one. This is a VOX circuit that uses a FET as the input amplifier to avoid loading down the source. __ Designed by Tom Alldread VA7TA
Building '29-Style Part 1 - Most hams in the late 20's and early 30's seemed to be using simple transmitters...one or two tubes at the most. No doubt the poor economics of the time made it difficult to build anything really elaborate but it didn't seem to stop them from getting on the air with whatever they could put together. __ Designed by VE7SL - Steve
Building '29-Style Part 2 - When it comes to putting a transmitter together for the BK, there are a lot of choices! My advice for a first-build '29 rig would be either a simple TNT or a Hartley-style oscillator. Both are easy to get operating and, when correctly optimized, are capable of putting out a nice-sounding signal. __ Designed by VE7SL - Steve
Building a simple crystal radio - A crystal radio is the distilled essence of a radio. it has very few parts, it needs no batteries or other power source, and it can be built in a short time out of things you can find around the house. __ Designed by Simon Quellen Field
Building an RF Remote Control System - With a handful of inexpensive components, a little creativity, and the power of PicBasic, you can build some pretty outstanding robotics creations as Rob Arnold proves with his Ruf-Bot project. __ Designed by Rob Arnold
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