Waterfall rec tab - voxo22/hackrf-spectrum-analyzer GitHub Wiki

Waterfall parameters

Waterfall

This checkbox starts/stops the Waterfall movement.

Palette start

On the right side of the spectral chart, a narrow strip (palette) is displayed, which represents the color distribution of the amplitude magnitude on the waterfall. This strip can be moved up or down on the Y-axis, depending on how you set the palette start slider. The slider sets the blue lower limit to the magnitude of the smallest amplitude in dBm.

Palette length

On the right side of the spectral chart, a narrow strip (palette) is displayed, which represents the color distribution of the amplitude magnitude on the waterfall. This strip can be resized along the Y-axis, depending on how you set the palette length slider. The slider sets the ratio of the color scale distribution to the amplitude range in dBm.

Speed

This slider sets the speed of the waterfall scrolling. However, decreasing the speed will result in some very short pulses not being displayed. To not miss any short amplitude change on the waterfall, set the speed to 10.

Recording parameters

Data Log Interval

If you plan to make a DATA record, first select the data collection interval. Statistical data is collected from the PEAK curve, this curve must be displayed. You can select the recording:

  • 1x per minute
  • 1x per second
  • 1x per fraction of a second (1/10s)

The last option will create the largest file in the same amount of time.

On the Parameters tab it is recommended to set:

"Peak Fallout Time = 1" for any "Data Log Interval" option

"Peak Hold Time = 0" for the interval 1x per 1/10 second
"Peak Hold Time = 1" for the interval 1x per second
"Peak Hold Time = 60" for the interval 1x per minute

Video area

If you plan to make a VIDEO recording, first select the area of โ€‹โ€‹the screen you want to record.

You can choose to record:

  • SPEC - only the spectral chart
  • SP+W - spectral chart and waterfall
  • FULL - full screen (including the Control panel)

The last option will create the largest file in the same amount of time.

Video format

If you plan to make a VIDEO recording, first select the file format.

You can choose to record in:

  • GIF animated - original color and sharpness, bitmap compression, nonlinear timing, demanding on disk space and buffer size (usually suitable only for a few seconds of video)
  • MP4 - H.264 compression, can be slightly discolored and softy (you may want to use thicker lines), linear timing (the timestamp on the image corresponds to the real playback time), unlimited recording, saves disk space

Note: the GIF format is more suitable for small, a few-second recordings, for publishing e.g. on websites. The GIF format preserves the original color of the image, usually automatically plays endlessly and you can publish it as a regular image. However, the file has large size after a few seconds and the spectrum analyzer saves it sequentially to the buffer. Therefore, do not use GIF for several-minute or hour-long recordings, the buffer may overflow and the system may crash.

Warning: even after turning off the recording to GIF, it may take a while before the file is accessible (the buffer must be completely flushed to the file).

Video resolution

If you plan to record VIDEO, first select the image resolution.

You can choose the size: 360p, 540p, 720p or 1080p

Note: Video resolution is limited by your screen resolution.

Video framerate

If you plan to record VIDEO, first select the video framerate. For a smooth GIF animated image, 15 fps is enough (non-linear timing), for a smooth MP4, you must select at least 20 fps. If you plan to record, for example, only sequential screenshots, select 1 fps.