Tunable RF bandpass filter ?

Discussion in 'Wireless & RF Design' started by cam0, Aug 15, 2010.

  1. cam0

    Thread Starter New Member

    Mar 23, 2010
    Hi there,

    I am trying to build a cheap frequency detector. However, I am kind of stuck at the point of designing a tunable filter. Actually, I'd like to be able to tune my bandpass filter between 300 to 800 MHz (with a BW of let's say 20MHz). I have no idea how to do that, except by using an adjustable Capacitor.
    What I am thinking about right now, is to put different filters for well known frequencies: 315MHz, 418MHz (BW will be smaller here), 433MHz, 815MHz, 868MHz and have a sort of switch (jumper ?) to choose between them, it sounds like the easiest way of doing to me.

    What do you think ?

    Thank you,