noise filter

160 meter low noise antennas experiments - VE7CA experiments on 160 meters band antennas, looking for better performances on reception.

Noise Reduction on 40m Priority listing - DF9CY implementation of W1HIS suggestion of inserting a common mode choke into a 40m antennas feed-line.

Timewave - Sells leading-edge voice and digital communications products to the world-wide military, government, industrial, and amateur radio marketplaces. Bluetooth Remote Audio/PTT, Rig Controller with Audio & PTT , HamLinkUSB Rig Control, Noise filtersm antenna analyzers, Multimode Data Controller, TNC, Packet Radio Terminal Node Controller. USB2RS232

MFJ Enterprises  ^pop - MFJ manufacturer of ham radio antenna products, antenna tuners, antenna analyzers, morse code & CW, SWR wattmeters, antenna accessories , power supplies, audio filters, TVI filters, baluns, coax switches and more

Filtronetics Inc - Maker of filters, oscillators, cristals Coils, Toroidal Inductions, Solenoids, Bifilar wound Solenoids, Trifilar Solenoids and Transformers Located in Kansas City, Missouri

Hioki - Memory recorders, Power meters, testers and multimeters, noise testers, signal generators

The KA7OEI FT-817 pages - FT-817 Radio Modifications, Improving the FT-817 Noise Blanker, increasing output power, using rechargeable cells, epanding frequency range

Using Crystal Filters in FT-897D - Installing these filters is a big improvement in the quality of the rig of the Yaesu FT-897D

RadioWare - Products and books for the radio hobbist. Antennas, Coax cables, filters,Lightning Protection, Wire & Cable, Books

Filtroid - Filtroid is an extremely easy-to-use program for synthesizing microwave filters. It can be used to design practically all filter types from audio to microwave frequencies as well as amplitude and delay equalizers and attenuators.

ScopFIR - Free windows comprehensive tool for Finite Impulse Response (FIR) filter design

FilterCAD - A free computer aided design program to help users without special expertise in filter design to create filters using Linear Technology's monolithic filter ICs. With FilterCAD, you can design lowpass, highpass, bandpass and notch filters

AADE Filter32 - ADE Filter Design and analysis is a free for download windows program to design filters

AADE Filter Design - Freeware windows programs to design Butterworth, Chebyshev, Elliptic (Caur), Bessel, Legendre and Linear Phase low-pass, high-pass, band-Pass, and band-reject filters. Coupled Resonator band-pass filters

DXFile - Windows shareware logging program, offer several features like packet radio interface, web cluster, grid square, beaming directions, qsl manager lookup, dx spot filtering by F6GQK in french.

Spectrum Analyzer Real-time FFT - Eight-channel Audio Spectrum Analyzer is a set of Real-Time Multi-Channel Gauges for investigation of data accepted from any ADC you will want or 16-, 24- and 32-bit ADC of sound card. WDM drivers support. FFT Spectrum Analysis, OscilloScope, Frequency counter, AC/DC voltmeter, Signal-to-Noise Ratio, Signal-to-Noise and Distortion, Spurious-Free Dynamic Range, Effective Number Of Bits, Total Harmonic Distortion, Inter-Modulation Distortion, Phase Shift. Special modes of dual-channel FFT spectral analysis: Separate channels spectra, Spectra of digital sum, difference, product of two signals, Spectrum of digital product of original signal and its fundamental, Spectrum of Real and Complex Transfer Function, Cross Spectrum. Standart weighing of spectra according IEC and CCIR. Oscilloscope modes (for dual-channel ADC) are: original signals, sum, difference, dependence of one channel on another, amplitude distribution of input signals.

Design 435/145 MHz diplexer filter - This example shows how SERENADE 8.7 can be used for help designing a contiguous lumped element diplexer by HA8ET

The Ladder Filter - Article by Lloyd Butler VK5BR

TVi Basics - making filters - TV Interference filters, making TVI filters, coaxial filters to eliminate TV interferences caused by radio frequency

5th order High Pass VHF Filter - Sometimes many VHF-UHF modern transceivers have problems with BROADCAST Interference and CROSS-modulation from FM commercial broadcast stations this article shows a simple Batteworth HI-Pass VHF Filter to reduce this problem

Design RF Filter

Low Pass Filter Construction - Low Pass Filter Module Construction Manual

Low Pass Filters - Article explaining electronic network of low pass filters

KI5YN QLF Filter - A microprocessor based interface designed to go between a standard Morse code key and a radio transmitter. The circuit receives a signal from the key, processes it, and re-transmits it to the radio.

Noise Figure Meter with a Spectrum Analyser - A relatively simple automatic Noise Figure (NF) meter was developed which is using a spectrum analyser as the receiver and logarithmic power detector.