low pass audio filter

Small Loop Antennas  ^pop - Experience and practical use of magnetic loop antennas, by N0HC

F9HS VHF EME - My hamradio activity : very high frequency communications using the moon as a passive reflector.

NASA Online VLF Receiver  ^pop - Hear VLF audio from NASA online VLF radio receiver in Huntsville, Alabama.

Microwave audio samples - 10GHz Rainscatter audio files

TE Systems - Manuf RF power amplifiers wideband+narrowband for Commercial, Defense, OEM and amatuer markets. Also low-noise rf amplifiers

Valcom Fibreglass Whip Antennas - Manufacturer of Fibreglass Whip Antennas, Low and mediun Frequency, HF and VHF Antennas Specialized in the design and manufacturing of a full range of Beacon (MF), AM Broadcasting 540 - 1700 KHz, HF 1.7 to 30 MHz, VHF 30 to 156 MHz and UHF 200 to 500 MHz antennas.

50MHz Sound Archives - Real Audio sound archives from H44PT cycle 21. Also from cycle 23 G8BCG, Z2/G8BCG, ZB0/G8BCG.

VLF Natural Radio Discussion Group - Discussion group dedicated to those who enjoy monitoring radio frequencies in the VLF radio spectrum and slightly below the VLF spectrum (3-30 KHz).

KH6FOO Pages - Hawaii-Californian Tropo ducting reports

49MHz Hobbyists Site - A website and email reflector for hobbyists in the unlicensed 49MHz low-power band.

DART - Clean up audio files and record high quality audio CD's!

CW Skimmer - Multi-channel CW decoder and analyzer for Windows 98/ME/2000/XP. Simulatneously decode ALL cw signals in the receiver passband - up to 700 signals can be decoded in parallel and extract call sign

EchoFilter - EchoFilter uses the soundcard of a PC to process income audio signals in real-time. The narrow filter bandwidth allow the extraction signals and sounds from the audio signal that may normally be close to inaudible. It is intended for radio HAMS, hobbyists, researchers, scientists and students in the DSP field.

Cluster monitor - Cluster monitor is a tool for web and telnet clusters monitoring. The program shows spot history, the latest spots are shown in a separate window with full information about the DX, announcements, WWV propagation, and full sorting and filtering capability. Full support for AALog and AAVoice by RZ4AG, DXAtlas by VE3NEA. Integrated dial-up support.

HamGrids - Windows application that will allow you to perform calculations with the popular Maidenhead Grid Square system. This grid system is used worldwide by amateur radio operators for many aspects of ham radio.

MacDSP - Digital filter for Macintosh computers with a PowerPC processor

QRS 2.05 - A slow CW and DFCW TX program for Windows, works well with Spectrogram. By Rik Strobbe ON7YD

MRP40 Morse Decoder  ^{updated  pop} - Program to receive morse code via sound card, Windows 9x/Me/XP, it allows to transmit morse code from the keyboard. Includes a comfortable Audio Analyzer Display. Successor of known MRP37

RX-PSK31 - Easy to use Audio Spectrum and PSK31 decoding program specially designed for SWL's who don't need TX or for anyone who just like to monitor PSK31 or analyse signals. Adjustable DSP and Spectrum settings for audio and frequency spectrum to set for best decoding of PSK31.

Ham Radio Deluxe Logbook - HRD Logbook v5 is a freeware windows logbook program that offer full control of your radio, Rotor control, support for many db engines, multiple logbook, dx cluster client interface, band maps and solar status report and audio recording

Simplex - SIMPLEX is a free windows program which transforms any transceiver into an audio repeater. It works on HF, VHF, UHF etc with SSB, CW, FM, packet, SSTV and every modulation mode.

GSpec - Spectrum Analyser for Win9x/2000 and NT, that will display audio input to your sound card in the Frequency and Time domains

Analyzer2000  ^pop - Superfast analyzer for audio and radio signals

The Radio-Frequency Ground - You were told that your audio was no good, that you had "RF in your audio ? This is also known as RF feedback

Radio Shack Special - Here's an amazing one transistor FM radio that has amazing sensitivity, selectivity and great audio output