Sometimes, it is useful to transmit a low-power radio signal to create a beacon, to send a signal carrier to a near receiver, to transmit in QRP or QRPP mode, and so on. The circuit shown here is very ...

Note: we are working to recover the figures for this article. The process of designing a short-range radio system can be complex and often involves many project tradeoffs (Fig. 1). With a little ...

This article is intended to introduce the beginner to the interesting and challenging art of high frequency radio design. It is also intended to entice the seasoned professional to take a deeper look ...

With this circuit, a single transmitter and simple set of user pushbuttons can initiate one of four different outputs, two at each of two remote receivers with very different applications. The ...

Joshua R. Smith receives funding from the National Science Foundation, the National Institutes of Health, the Department of Energy, the Department of Defense Medical Command, DARPA, Bosch, and Amazon.

For good reception, a radio must have good selectivity (selectivity is a radio's ability to separate weak stations and strong stations on the FM dial) and good sensitivity (the ability to receive weak ...