noise filter

VLF-LF and the Loop Aerial - The article discusses the theory of loop aerials for receiving and how they reduce the level of local noise by Lloyd Butler VK5BR

Importance of noise reduction in wires antennas - An old post by John Doty about effects of noise in longwire antenna.

Shortest Vanity Callsigns - This is a service for finding the shortest available vanity callsign in your amateur radio class. It filter through all possible callsigns and provide just the unused ones weighted by their length in morse code or their actual number of letters.

Ham Radio Talk - The amateur radio forum with more signal and less noise.

Accute Micro - China supplier of ceramic bandpass filters in standard resonator sizes of 2~6mm , 8mm , 10mm and 12mm with freqency from 400Mhz~4Ghz and sections 2~10

Duplexers for Ham Radio repeaters - We produce duplex filters and antennas for 2m,70 cm and 23 cm repeaters.

RF Circuit design basics - Ebook by Akira Matsuzawa Tokyo Institute of Technology, Building blocks in RF system and basic performances, Device characteristics in RF application , Low noise amplifier design, Mixer design and Oscillator design

Garth RF Filters - ATV Filters, RF filters dealer

SWL DX Cluster - Web cluster for swl's. With many features, including filters, search, SWL Database, lookups

LCLAYOUT drawing software - Simple inexpensive program that allows L-C filters designed by PCFILT or S/FILSYN which are to be built using air wound inductors and single layer capacitors cut from alumina or duroid substrate materials

ALK Engineering - Alk engineering - filter design software and consulting

FILPRO - The most flexible and powerful Microwave and RF Filter and Multiplexer Design Software

Nuhertz Technologies - Leading supplier of low and high frequency electronic filter design products for the design of wireless telecommunications equipment, semiconductors and more

Omicron filter design - Electronic filter design software by omicron is the best for developing active filter, passive filter, and digital filter - check out our products and ordering information.

Filter Wiz Pro - Schematica software filter design program

RSCW - RSCW is a Linux/Unix program for decoding morse signals using the computer's sound card. It has been written/optimized for digging weak signals out of the noise.

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.

1.8-54 Mhz Low pass filter - An easy to make HF low pass filter form high power by k8cu

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 filters are generally limited to frequencies above 200 MHZ because their size is slightly longer than 1/4 wavelength

Interactive Digital Filter Design - This is an interactive filter design package, for designing digital filters

LC Filter Design - This is an interactive design package for designing analogue (i.e. hardware) filters made of inductors and capacitors (Ls and Cs).

Online Microwave Filter Design and Analysis - This site is dedicated to design and analysis of micro- and millimeter wave filters from 0.5 to above 100 GHz.

VHF signal generator - a simple VHF signal generator in order to measure the characteristic of low pass filter.

A single board no tuning 23 cm transverter - This transverter uses bandpass filtering with printed hair-pin filters. By KK7B