گروه خدمات فنی مهندسی رهگشافن

NDBfinder allows you to use your PC and soundcard to receive, detect, identify and log NDBs (Non Directional Beacons used for maritime and aeronautical navigation), that would otherwise be too distant or faint to detect. NDBfinder exploits the fact that almost all navigation beacons send their idents are precisely regular intervals. Using a unique combination of two Fourier Transforms and a Boxcar Integrator, NDBfinder is able to superimpose many successive indents and in doing so it can retrieve signals that are buried in the noise. This makes it possible for NDB DXers to detect beacons far beyond the normal reception range.

NDBfinder Features >> NDBfinder detects NDB transmissions using the sound card in your PC. You need a suitable LF/MF band radio receiver tuned to an appropriate frequency in the navigational beacon band. >> The program processes the audio signal from the receiver and shows you signals that are hidden in the noise.  >> Signal View - displays the raw audio signals on your PC screen in a diagnostic display which helps you to set up the connection and the soundcard.  >> Spectrum View - displays a scrolling spectrum of the received audio signal frequencies on your PC screen. You see an immediate display of the mose code identification if the beacon is received with good strength. By default the display covers 0-3kHz but other audio frequency ranges can be specified by the user.  >> Spectral Density display - shows the overall Spectral Density of the accumulated data. On this display, you can discover morse code identifications that are too weak to be seen on the Spectrum View.  >> Periodicity display - shows an analysis of any periodicities in the pattern in the chosen audio frequency. If there is a morse code identification buried in the noise at the selected audio frequency, its periodicity will be betrayed by a spike in this display.  >> Integrated display - shows the result of a boxcar integration of the signal at the chosen frequency and with the specified period. If the signal is processed for several minutes, huge improvements in the signal-to-noise ratio can be acheived. This can make the difference between a signal being undetectable and being easy to identify.  >> Beacon Identification - The program can decode and display the three-letter identification of the signal that you have detected.  Log file - The program can automatically save the identification, the audio heterodyne, and the ident period to a log file.  >> Playback - The program can play back the audio resulting from addition of multiple idents so that the signal can be identified aurally.  >> - The program can execute a command to allow fully automated monitoring and surveying.