Here's a two part project for an RF Spectrum Analyzer from QST Magazine. Even if you don't build the project there's some great information in here regarding RF filters, mixers, oscillators and more.

Let’s say a corporate engineer or a consultant is coming to your station to diagnose and repair a problem using an RF spectrum analyzer. This would be a great time to schedule a meeting with your ...

RF signal observation has evolved from yesteryear’s spectrum analyzer to today’s RF recorder. Swept spectrum analyzers, FFT analyzers, and real-time signal analyzers all had limitations. Today’s RF ...