This audio noise filter circuit is a bandpass filter for audio frequency band. It filters unwanted signals that are lower or higher than the audio frequencies. It has 2 filters: a low pass filter and ...

Most universal radio receivers have a very wide bandwidth that is not particulary for radio amateurs. The better models with narrower bandwith are almost always priced higher, too high for the reach ...

Download Volume 3 of the Bob Pease eBook series. This morning, some darned kid engineer (rather bright for a 15-year-old!) asked me if I could show him anywhere he could add a little narrow-band boost ...