I'd like to build a 3rd order low pass filter, cutoff ~40mhz, impedence at 28mhz of 50Ohms?

Hello All. I want to build a 3rd order low pass filter with a cutoff ~40mhz. I'd like to build this in a metal box seperated into two compartments with a pi filter in each. What components do I need? The input output impedence should be ~50 ohms at 28mhz. It stray capacitence a problem? Thanks?

sound918 years ago
I know the general idea of how to do this, but I don't know the exact values of the components you need. The book you need is Lancaster's Active Filter Cookbook. It explains all of the math for filters and the different types.