Everyone likes to talk about their glory days, in fact, I believe there is a song about this phenomenon. My high school science fair project occupied most of my glory days. Today I have posted complete photos, all documentation, and schematics from this project. It is a 1.425 GHz radio telescope receiver. The concept behind this system was that you use a swept frequency spectrum analyzer to detect, then, blank out narrow-band in-band RFI signals. This is necessary when operating a radiometer in an urban environment, where, RFI signals from computers and other things are prevalent and when it is desired to operate your radiometer over a (relatively) wide bandwidth. Similar techniques are utilized in other radiometer projects, except now the implementation is digital, using wide band digitization and FFT's. The implementation of my high school science project was completely analog. Quite the learning experience!
Hope that you can use some of these ideas on your own projects,