CwGet—A Morse Decoder
With High Visibility Text

 

   This article is for amateur radio operators with impaired vision who want to translate Morse code into high visibility text. CwGet is a Morse decoder program with built-in options for large type and high contrast colors. No special hardware is required. You can use a single cable to connect the speaker output from a receiver to a computer with a sound card.

CwGet was written by Sergei Podstrigailo, UA9OSV, the author of TrueTTY for digital modes. The two programs have some similiar controls and menus, including a wide range of options for fonts and colors.

   The program is shareware. When the software is registered after a free trial, it is upgraded to save your menu selections as default settings.

What CwGet Does

   • Translates incoming Morse code into text using the font and

          colors of your choice.

   • Locks onto a signal (AFC).

   • Automatically adjusts to the speed of a CW signal.

   • Integrates with AALog software.

What CwGet Does Not Do

   • CwGet does not transmit. Send code as you usually do. Or, type

          text on a computer keyboard, and send it using CwType, a

          separate free program by the same author.

   • CwGet does not decode every signal you can copy. As usual

          with decoders, poorly timed code or a noisy signal can cause

          errors.

How To Use CwGet

   Some eHam reviewers suggest using the program as an aid to your own copying—to check an occasional word or to record the exchange information in a contest. Your own skill is essential when the signal to noise ratio is too low for a decoder.       

   Decoded text is also useful when you practice receiving CW.

Program Description

   Figures 1 and 2 are screen captures from a CwGet window with the decoded text in 24 point bold type. The figures are actual size. On a typical display set for 120 dpi the letter height is 0.3 inch. For larger text you can use a larger screen or magnification software.

Figure 1.  Part of a CwGet window (actual size).

Figure 2.  Part of a CwGet window with high contrast text.

   The top pane in each figure shows the spectrum of received signals. A vertical red line marks the frequency of the CwGet audio filter. When AFC is on, this line tracks the signal if it drifts, and a small red line stays at the original frequency.

   The small black vertical line in the spectrogram is a movable marker that is useful when tuning a transmitter. The procedure for using it is described in the article on configuring CwGet.

Detecting Code

   The bottom pane in each figure is an oscillogram of the received signal. The horizontal red line is the detection threshold. When the signal exceeds this voltage, the program registers a code element—a dot or dash. Using the oscillogram, you can decide whether the signal-to-noise ratio is high enough for accurate decoding.

There are two ways to set the threshold:

(1) With Auto-Threshold off, click on the signal at the chosen level.

(2) With Auto-Threshold on, the program sets the level and

          changes it when the signal strength varies. A second

          red line shows the noise level used to set the threshold.

   The buttons in the control bar above the oscillogram are controlled with mouse clicks. The image of each button appears slightly raised (off) or depressed (on). The effect is subtle, and it may be easier to use the second red line on the oscillogram as an indicator that Auto-Threshold is on. Movement of the vertical red tuning line on the spectrogram indicates that AFC is on.

Summary

   CwGet is a Morse decoder with a range of built-in options for displaying received text using high-visibility fonts and colors. It can also be used with a magnification program. No special interface hardware is required.

   A separate article describes how to configure CwGet.

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.

Email:  HamRadioAndVision "at" gmail "dot" com.

rev. 11/5/2011

                   Related Article: Configuring and Using CwGet

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