Welcome to our site! EDAboard.com is an international Electronic Discussion Forum focused on EDA software, circuits, schematics, books, theory, papers, asic, pld, 8051, DSP, Network, RF, Analog Design, PCB, Service Manuals... and a whole lot more! To participate you need to register. Registration is free. Click here to register now.
Another good source for simple designs is the amateur radio handbooks put out by the US ARRL and the UK RSGB. Also, any older general purpose radio engineering handbook will work. Check in your local library for the one by Terman from about 50 years ago.