User Interface Visibility


   This article is for vision-impaired ham radio operators interested in the visibility of a FlexRadio user interface. PowerSDR is the software that "defines" older model FlexRadios. It controls all digital signal processing and runs the user interface.

   PowerSDR is free, open-source software developed and distributed by FlexRadio Systems.

User Interface

   FlexRadios are operated using the control panel (Figure 1) displayed on a computer screen.

Figure 1.  PowerSDR 2.2 control panel.            www.flex-radio.com

    The window dimensions are adjustable from a minimum size up to full screen. On a typical 22" display with default setting of 96 dpi, the minimum window measures 13.25" diagonally (11.4"W x 6.9"H).

   The Display Mode pull-down menu on the panel lets you choose how data are shown in the large central Display area. Figure 1 shows the Panadapter Mode. Other choices include Spectrum Mode (filter output), Waterfall, Scope, Phase (for digital modes), and two combinations, Panafall and Panascope.


   The visibility of the face plate can be improved by choosing a skin with high contrast colors (Figure 2).

Figure 2.  A higher contrast face plate.

    The colors used for data are also customizable. For example, Figure 3 shows the level of detail for colors used in the Display window.

Figure 3.  Sub-tab for customizing the Display window.

Small Text

   Except for the VFO frequency and the multi-meter readouts (0.2" high numerals), text and data on the control panel are 0.1" or smaller on a typical 22" screen, and PowerSDR has no option for enlarging them:

     • They do not increase when you expand the window to fill the screen. The panadapter window gets larger, but text and controls remain the same size.

     • Some ham radio programs allow you to increase the dpi setting of the LCD display, but enlarging the PowerSDR panel this way causes parts of some controls to disappear.

   The text can be enlarged by using a bigger screen and/or a screen magnifier program.


   On a big screen the PowerSDR user interface for FlexRadios can display a large panadapter window. The program also has high contrast color options that improve visibility. Controls and text are small. They can be enlarged by using a bigger screen and/or a screen magnifier program.

Author Information

   Peter DeNeef, AE7PD, is an Extra Class amateur radio operator in the U.S. This Web site has no ads or conflicts of interest.

rev. 12/1/2014

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