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4.19.7 - RF Waterfall File Format

Waterfall format files are text files with four numbers per line. The first number, the color number, must be in the range 0 to 255 except for the last line. The three numbers after the color number are the RGB values, and each of these must be between zero and one.

The first color line must start with color number zero.

The last color line line must start with with color number 255.

After the last color line is the terminating line; this must have a -1 for the color number, followed by three zeros.

These color numbers must be in ascending order, that is, each color number must be followed by a higher number.

The other three numbers on the line are red, green and blue in that order. 0 is no brightness, 1.0 is full brightness. Here's an example, which I will explain below:

----- file begins below ----
0 0.0 0.0 0.0
45 1.0 1.0 1.0
60 1.0 0.0 0.0
75 1.0 1.0 0.0
90 1.0 1.0 1.0
-1 0 0 0
----- file ends above ------

Note:

• 1st color line starts with color 0
• note color numbers always increase
• last color line ends with color 90
• terminating line is always -1 0 0 0

The first two lines will cause the colors from 0 signal strength to 45 signal strength to vary from black (0 0 0) to white (1 1 1).

The second and third lines will cause the colors from 45 signal strength to 60 signal strength (about one S-Unit of difference) to vary from white (1 1 1) to red (1 0 0).

The third and forth lines will cause the colors from 60 signal strength to 75 signal strength to vary from red (1 0 0) to yellow (1 1 0).

Lastly, the fourth and fifth lines will cause the colors from 75 signal strength to 90 signal strength to vary from yellow (1 1 0) to white (1 1 1). Above 90, the color will continue to be white.

Then there is the required terminating line; the (-1 0 0 0) signals the software that the palette definition is complete. Don't forget it!

For your reference, 15 steps is about one S-Unit at 10 dB/Div; although you can modify that quite a bit with I and C. I have found that making color 0 black, then 45 a dark color, then 60 moderately dark, then 75, 90 and 105 colors of increasing perceptibility (usually brightness, but not always... we respond to colors non-linearly) provides a good palette where the backdrop of the waterfall can be adjusted to be uniformly dark, while signals are bright and are easy to distinguish in terms of increasing strength. This is my favorite palette thus far:

----- file begins below ----
0 0.0 0.0 0.0
45 0.0 0.0 0.25
60 0.0 0.0 0.5
75 1.0 1.0 0.0
90 1.0 0.0 0.0
105 1.0 1.0 1.0
-1 0 0 0
----- file ends above ------

Note:

• black (dark color series)
• dark blue
• moderate blue
• yellow (1st bright color)
• red (intermediate color)
• white (brightest color)
• terminating line, as always: -1 0 0 0

Starting the bright colors at 75 (about S5, relative to the palette base) allows enough leeway with the palette adjustment slider so that the adjustment slider can shift a very high noise level below the bright colors. If your color selection starts the bright colors too soon, some high noise levels will not fully adjust to darkness, which can make it difficult to see the actual signals.

Note: Some of the GUI controls in SdrDx use keystrokes to make adjustments; when those controls are used, they "capture" the keyboard and the new keyboard-driven features cannot work, because the keystrokes don't always make it to the new features. In order to work around this, the "Keys" button allows you to click once to explicitly send the keystrokes — all of them — directly to the code that implements the additional keyboard-driven features. In addition, clicking on the waterfall / graph display will capture the keystrokes correctly.

Note: Availability of F-KEYs and certain other keystrokes varies from one Mac to the next, depending upon the user preferences settings for the keyboard shortcuts. Personally, I prefer to have the F-KEYs available for applications, rather than dedicate them to the OS functions, so I move the OS functions to OPTION F-KEY using the system keyboard preferences and that allows other software to be much more capable, including SdrDx.