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Ham Radio School Visualization Apps

  • Writer: Stu WØSTU
    Stu WØSTU
  • 8 hours ago
  • 4 min read

A big part of the Ham Radio School method of helping students prepare for license exams with real comprehension of radio topics is visualization. Particularly when it comes to some of the more technical processes involved in radio science and engineering, we have found that student understanding of these topics extends directly from our extensive use of graphics, video, animations, and other tools that help them visualize these processes. As such, we provide ample visual models in our books, in our online course video lessons, and in our optional depth learning media at HamRadioSchool.com.


Visualization of radio processes is key to students "really getting it."
Visualization of radio processes is key to students "really getting it."

However, we recognize that while passive observation and consideration of these visual models can help instill solid comprehension, there are even more effective tools that blend visualization with student interaction. Web-hosted visualization apps that allow the student to experiment with the visualization model, changing input parameters and observing the results, is more engaging and more effective than passive observation for most learners.

With this philosophy in mind, we have recently developed several visualization applications to allow students to experience learning interaction with some of the more challenging radio processes. These apps are generally geared towards the Technician License student, but more advanced students can also benefit from fiddling around a bit with them. We invite you to give them a try, and to provide us with feedback on them, if you like, in the spirit of continuing improvement.


We recommend a full-size monitor for the best experience with these apps. While they are mobile device responsive, the displays and controls fit much better for ease of interaction on the larger display real estate.


Provide input to the app by selecting and constructing a baseband modulating signal. Sum together modulating signal sine waveforms of different frequency and amplitude to see the resulting modulating signal and its impact on the modulated RF signal. Adjust the carrier frequency, the carrier amplitude, and the speed of the dynamic display, as desired. Alternatively, select the microphone option to input your own voice or sound and observe in real time the complexity of the signals. Freeze the displays for careful examination of the signals, or take a snapshot of the displays in .png format for downloading.


The AM Simulator lets you construct complex modulating signals from individual sine wave components and view the modulated carrier signal that results.
The AM Simulator lets you construct complex modulating signals from individual sine wave components and view the modulated carrier signal that results.

Identical to the AM Simulator, but producing a visualization of a frequency-modulated RF carrier. Build a modulating signal with various sine wave inputs, or use your microphone for complex audio input. This simulator adds a slider control for FM deviation level, adjusting the relationship between baseband amplitude and RF carrier frequency deviation. The carrier deviations are somewhat exaggerated so that they are readily observed, as FM signal deviations are quite subtle. (A typical FM signal's 5 kHz deviation will result in wavelength variation of only about 0.14 millimeter.)


Like the AM Simulator, our FM Simulator allows the construction of complex baseband signals that are reflected in a simulation of the FM carrier deviations.
Like the AM Simulator, our FM Simulator allows the construction of complex baseband signals that are reflected in a simulation of the FM carrier deviations.

Enter a string of text, select a words-per-minute send speed, and view the carrier waveform on-off patterns or Morse Code along with a read out of the characters represented. Adjust the tone as desired that is produced with each dit and dah, all with perfect CW cadence between characters and words.


The CW Simulator lets you enter a text string and see and hear it accurately encoded as a CW signal.
The CW Simulator lets you enter a text string and see and hear it accurately encoded as a CW signal.

Frequency Shift Keying (FSK) Digital Mode Simulator:  https://hamradioschoolquiz.com/hrsapps/fsk-simulator.html

Explore the fundamentals of digital modulation using FSK. Enter a text string to encode with 8-bit ASCII and select one of three FSK tone quantities: 2-FSK, 4-FSK, or 16-FSK. See and hear the message encoded using your selected FSK method, with each unique tone symbol color-coded for differentiation in the display as well as represented in a stairstep diagram. The commensurate binary digital values are also displayed under each color-coded wave segment, and each resultant text character is displayed with an underscore grouping the eight binary values that represent it. Zoom and display scroll controls are provided to enlarge the display when needed for careful examination of the results Easily compare symbol rates (baud) and data rates across the different FSK methods.


The FSK Digital Mode Simulator illustrates the basics of digital modulation with visuals and tones. Enter a text string to see and hear it encoded into ASCII binary code.
The FSK Digital Mode Simulator illustrates the basics of digital modulation with visuals and tones. Enter a text string to see and hear it encoded into ASCII binary code.

SWR and Wave Superposition Simulator:  https://hamradioschoolquiz.com/hrsapps/waves.html

Students often have a tough time visualizing the standing waves in a transmission line that are produced when an impedance mismatch exists at the antenna feed point. This app illustrates the voltage dynamics inside a transmission line, displaying a forward sine wave signal traveling right, a reflected sine wave signal traveling left, and the resultant sum of the two. The student can see the high voltage amplitude of the resulting standing waves and the low voltage amplitude of the standing waves. The ratio of these high and low voltages is computed and displayed as an SWR value. Watch the SWR increase and decrease as the reflected signal amplitude is adjusted. Use the slider controls to change the propagation speed, the amplitudes of forward and reflected signals, and the frequency of the wave. Independently display only the forward signal, only the reflected signal, or only the summed resultant, as desired.


Watch forward and reflected transmission line voltage waveforms be dynamically summed into resultant standing waves for SWR determination. Change the signal amplitudes and observe standing wave and SWR impacts.
Watch forward and reflected transmission line voltage waveforms be dynamically summed into resultant standing waves for SWR determination. Change the signal amplitudes and observe standing wave and SWR impacts.

I hope you put our new visualization apps to good use for your own comprehension or for your instructional purposes. We will be using them for salient explanations in our online course video lessons beginning with the new 2026-2030 edition of the Technician License Course.


Enjoy fiddling with these apps, and if you have suggestions be sure to drop us a note with your ideas.


73,

Stu WØSTU

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