In a recent past issue of Electronics Now magazine¹, Of course there are plans out there to build transmitters and ironically they are cheaper and easier to build. As outlinned in a recent issue of Popular Electronics², there are many types of inexpensive transmitters for all type of
applications. Depending on distance of the receiving unit (a normal radio), will determine the type of the transmitter to build. For example, a one transistor transmitter will basically give you a distance up to 150 feet. A two transistor transmitter will can sometime reach distances up to 600 feet. Plans for both of these, along with others, are outined in pretty good detail in the magazine. In the future we will include information on telephone monitoring and
counter-measures. Please check back for updates. ¹ Electronics Now (July 1999) for reprint or subscription info go to 
In today's world, it seems like privacy is subject that comes up more often than it should. We have been analyzing different types of measures and counter-measures related to this topic. Some are simple and some more complex. 
they had plans for a great RF finder. In brief,
the device would detect RF signals between the frequencies 500khz and 2ghz. It has a 9 LED signal bar and earphone jack with volume control. Now, I could hear some people saying, what would I do with this. There are many applications for such of a device. One simple application is, if you were talking on a wireless phone and you walk into one room of your house and receive heavy interference. After you get off the phone you could use this device to aid you to find the source
of interference. The other application for this item, if you were under the suspicion that you think someone would be "bugging" you. This device would allow you to sweep parts of your residence for the existence of wireless transmitters.
² Popular Electronic (July 1999) for reprint or subscription info go to www.gernsback.com