Black Cat Systems
Follow our tweets!

Home
Purchase
News
Mac OS X Software
Mac OS 9 Software
Windows Software
Ham Radio iPhone/iPad
Linux Software
Documentation
Support/FAQ
Update Policy
Lost Reg Code?

Radiation Detectors
USB Icom CI-V Interface
MIL-STD-188 Interface

General Interest Programs

  Atomic Mac/PC
  Audiocorder
  Audio Toolbox
  Black Cat Timer
  Diet Sleuth
  iUnit
  Graffikon
  Graph Paper Maker
  Health Tracker
  Knitting Wizard
  Label Wizard
  Prog Audio Gen
  Sound Byte
  Synth 76477

Amateur Radio Programs
  Audiocorder
  Black Cat CW Keyer
  Cocoa 1090
  Cocoa RTL Server
  DGPS Decoding
  DX Toolbox
  Elmer
  eQSL Factory
  MatchMaker
  MININEC Pro
  Morse Mania
  MultiMode
  mySdrPlayback
  RF Toolbox
  SelCall
  Sonde

iPhone/iPad Apps
  ALE
  Atoms To Go
  dB Calc
  Clik Trak
  DGPS Decoder
  Drill Calc
  DX Toolbox
  Elmer Extra
  Elmer General
  Elmer Tech
  Feld Hellschreiber
  Field Strength Calc
  Function Generator Pad
  GMDSS
  Godafoss
  HF Weather Fax
  iAttenuate
  iFunctionGenerator
  iGeiger
  iSoundex
  iSoundByte
  iSweep
  iUnit
  Morse Mania
  ACARS Pad
  Morse Pad
  NAVTEX Pad
  Packet Pad
  PSK31 Pad
  SSTV Pad
  Photon Calc
  Rad Map Tracker
  RF Link Calc
  SelCall Tone Gen
  Sound Byte
  Sound Byte Control
  Spectrum Pad
  SWBC Schedules
  Synth 76477
  Synth Motion
  Transmission Line Calc
  Weather Calc
  Wire Calc

iPhone/iPad Bundles
  RF Calculator Apps
  Ham Radio Decoder Apps
  Audio Utility Apps
  Shortwave Weather Apps
  Ham Radio Exam Study Apps
  Shortwave Decoder Apps

Android Apps
  ACARS
  Audio Function Generator
  
DGPS Decoder
  HF Weather Fax
  NAVTEX
  Rad Map Tracker
  SelCall Tone Gen
  Sound Byte Control
  SWBC Schedules
  Wire Calc

About Black Cat Systems
Geiger Counter
Site Map
Our software for Mac OSX
Privacy Policy
Press/Media
HFunderground
Apple /// Emulator

Macintosh Links
Shortwave Radio
Pirate Radio
Spy Numbers Stations
Science and Electronics
Ham Radio Software
Geiger Counters


   

Display QRSS Transissions On the Go!

Godafoss displays a waterfall of the audio spectrum, letting you view QRSS, DFCW, FSKCW, and other slow transmission speed signals. You can place your device's microphone near the speaker or headphones of your radio to pick up the sound. Or, if you have a cable to directly connect them, that will work ever better.

A frequency axis is displayed to the right or bottom of the screen, depending on the direction the waterfall is running.

You can pan the range of audio frequencies by touching the screen and sliding with your finger, in the same direction as the frequency axis.

You can also pinch and zoom to adjust the span of frequencies displayed, up to a maximum of 0 to 20 kHz.

If you don't want to accidentally change the frequency range, tap the Lock button so it is highlighted. Panning and pinch/zoom will not affect the frequency range, so you don't accidentally change them.

When first started, Godafoss defaults to an FFT size of 4K, with a Hanning window. You can change these and other settings by tapping the Setup button, and a set of controls will appear:

The first two are sliders that set the minimum and maximum audio levels for the waterfall colors. Adjust these to get the best looking display for the signals of interest. Often you want a blue background, the minimum dB slider should first be adjusted for this. Then adjust the maximum slider for the strongest signal, often it is desired to make this red or pink, but you have the flexibility to set it how you wish.

The FFT size sets the number of sound samples used to compute the spectrum. Higher values provide better frequency resolution, but update more slowly, and can smear faster signals.

The window type controls what windowing function is applied to the data before the FFT is run. The window modifies the received audio data to reduce what is called "leakage" from non periodic signals. Leakage smears the signal over a wider frequency range. Experimentation will help you find he best settings. The following windows are available:

  • Rectangular
  • Hanning
  • Hamming
  • Tukey
  • Cosine
  • Lanczos
  • Blackman

Speedup allows multiple FFTs to be run on the same set of audio samples, shifted slightly in time, This can be useful when a larger FFT size is required, but the signal rate demands a faster update rate on the waterfall. A speedup of 1 means no speedup is applied, a speedup of 10 means that 10 FFTs are performed on each data sample.

Finally, you can change the direction the waterfall runs, to the left, right, up, or down.

Note that making changes to any of these settings only affects newly received audio, previously received audio already displayed on the waterfall is not affected.

You can take a screenshot of the waterfall by tapping on it three times. The screen will flash to let you know the picture has been taken, and it will be saved to your Saved Photos album. Then you can share your received signals with your friends.

Also for the iPhone and iPod Touch!

Visit the Godafoss FAQ page for full details on how to use the app.

Are you looking for a technology or radio related iPhone/iPad app but can't find one that does what you want? Have an idea for an app that you'd like to see? Contact us at info@blackcatsystems.com!


Email your comments and questions to support@blackcatsystems.com

Last modified May 31, 2015