500 KHz Low Pass Filter
- This article describes a shielded low pass filter
with a cut off frequency of about 500 KHz. It is built with components suitable for receiving, and was designed to use in front of a low frequency receiver for LOWFER work.
Homebrew a CW Filter
- An home-brewed morse code CW filter
with a central frequency of 800hz and a variable bandwidth from 230hz to 26hz by F5RDH in french.
Interdigital bandpass filter designer
- Fill out the form to design a bandpass filter
as described in the January 1985 issue of Ham Radio Magazine. These filter
s are generally limited to frequencies above 200 MHZ because their size is slightly longer than 1/4 wavelength
LC Filter Design
- This is an interactive design package for designing analogue (i.e. hardware) filter
s made of inductors and capacitors (Ls and Cs).