Configuring and Using CwGet
for Vision-Impaired Hams
This article is for vision-impaired amateur radio operators who want to use the CwGet Morse decoder. The program is described separately. This page is about configuring and using CwGet, including:
• setting up the sound card interface
• high visibility fonts, colors, and graphs
• tuning
During the free trial period, your settings are not saved when the program is closed. After you register (purchase) the program, menu choices become the default settings that are used when the program is restarted.
Sound Card Interface
No special hardware is needed. You can use a single cable to connect the speaker output from a receiver to a computer with a sound card. If a ground loop causes noise and interference, you can add RF isolators as described by WM2U.
To link CwGet to the sound card, click on the Interfaces tab in the Setup menu and select from the pull-down menu for the Input Sound Card.
To avoid over-driving the sound card, open the Sound dialog box in Windows Control Panel and select the Recording tab. Adjust the gain of the Microphone Input circuit so CW signals peak well below the top of the spectrogram. Also, if the noise increases faster than the signal when the gain is increased, the sound card is being over-driven.
CwGet can be used with a hardware interface designed for digital modes (RTTY, PSK31, etc). Many of these take fixed-level audio from an accessory jack on the transceiver, so changing the AF Gain will not affect the audio.
Tuning the Receiver
Receiver tuning with CwGet is a two-step process: Use the transceiver VFO knob to tune across the band as usual. When you hear a signal, click on the peak in the spectrum. You can also tune CwGet with the mouse wheel or the "Go To Max" button in the Control bar.
Tuning the Transmitter
Zero-beat tuning is often used to match transmitter frequency to an incoming CW signal. The two signals are mixed, and you tune the transmitter until there is no audible beat wave inteference.
In a 2002 eHam review of CwGet, WZ7I describes an alternative tuning method:
1. When you key the transmitter, the tone you hear is displayed on the spectrum. Right-click on the vertical black marker and drag it to the peak frequency. The location depends on the CW pitch setting of the transmitter, not the radio frequency. This step is only done once.
2. To answer a CQ call, use the radio VFO knob to bring the received signal peak over to the marker. The transmitter is now tuned to the other station.
High Visibility Settings
The Fonts and Colors menu in Setup has a wide range of fonts, styles, sizes, font colors, and background colors. Click on the "Set" button for any of the 11 categories in the menu. A preview box shows what the choices look like.
This menu also has optional high contrast colors for the graphs and backgrounds. To enlarge the graphs, click and drag the lower border of each pane.
Acknowledgments
Thanks to Sergei Podstrigailo, UA9OSV, for information about CwGet, and to Wesley Cosand, WZ7I, for describing transmitter tuning in his eHam review.
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. 3/20/2011
Related Article: Description of CwGet