RF & Radiation

Due to the huge interest in this project, I have just recently finished the NEW schematics. The older schematics were scanned and pretty poor quality. These new ones should make it considerably easier to recognize the parts used for the project. The Ming RF transmitter and receiver boards used for this project are relatively inexpensive and perform admirably considering the meager price. Using the quarter wave antennas, I have had some excellent results with operating distance as well as overall operation...

Modern high-performance transmitters require accurate monitoring of RF power, because most cellular standards depend on strict power- transmission levels to maintain an effective network. Regulation of transmitted-signal strength also lets you build lower cost systems. Figure 1 shows a waveform-independent circuit that provides a linear measurement of RF power. Sophisticated modulation schemes, such as CDMA (code-division multiple access) and TDMA (time-division multiple access) have obsoleted traditional approaches to RF power...

Sending Morse on a rig without a sidetone is not impossible, but is not particularly pleasant either. This battery-powered monitor has been designed to provide an audible indication of keying for those whose rigs lack a CW sidetone. Its sensor wire is wrapped around the transceivers coax no direct connection is required. Of course Morse isnt the only use for this nifty circuit it should also be useful any time you need a simple alarm that detects the presence of RF. RF collected at the sensor wire is rectified by a germanium diode. This produced a DC voltage that triggers a transistor switch...

RF is just way too cool not to use in your designs. But if you`re a newbie like me it is difficult to successfully build solid RF transmitters and receivers. When I started out I didn`t realize that the larger breadboard I was working off of was causing a lot of the signal deviance because the metal traces on the breadboard worked like small capacitors and changed my circuit dynamics. So after much research I found the Reynolds Electronics RWS and TWS 434 RX/TX pair...

This is an image Schematic. No Description available...

This project will show you how to build a circuit to control things remotely using the the Basic Stamp II and Ming RF modules. I am making a remote engine starter for my truck, but anything you can turn on and of with a Relay could be used in this project. Without any type of anttena the Modules can get 50 to 100 foot range, which is excellent considering there only 10 bucks each. However with a antenna much better range can be achieved. I got a range of about 200- 300 feet with a 1/4 wave antenna(an antenna that is 1/4 the lenght of the wavelenght of the signal) or 9.36"...

his circuit isn`t very sensitive, and could use a good wideband RF amp between the antenna and the detector diode...

This circuit can be used to "sweep" an area or room and will indicate if a surveillance device is operative. The problem in making a suitable detector is to get its sensitivity just right; too much and it will respond to radio broadcasts, too little sensitivity and nothing will be heard. This project has few components, can be made on veroboard and powered from a 9 volt battery for portability. My prototype shown below, worked OK on a Eurobreadboard...