D-STAR on a DV Dongle
for Hams with Low Vision
A DV Dongle is a small USB device that enables a personal computer to connect to the amateur radio D-STAR digital voice network. With this device you can use D-STAR repeaters and reflectors without a radio.
For hams with low visual acquity the DV Dongle has some advantages over a D-STAR radio. There are no channel memories to program, and the controls can be magnified on a computer screen.
This article describes the accessibility of the DV Dongle user interface.
A separate article describes D-STAR radio accessibility for blind and vision-impaired hams.
The DV Dongle was invented by Robin Cutshaw, AA4RC, and Moe Wheatley, AE4JY. It has a 1.5" x 3.1" x 0.6" translucent plastic enclosure with a single mini-USB plug and four, color-coded status LEDs. The device connects to a USB 2.0 port on a Windows, Mac, or Linux computer.
The Dongle requires a broadband Internet connection and a PC or Mac with a 2.0 GHz or faster CPU and at least 500 MB RAM.
The DVTool control program is available for Windows, Mac OS X, and Linux systems. Installation instructions are on the DV Dongle Web site.
Some cable modem/routers have restrictive firewalls that block the outgoing DVTool connection. In that case it's necessary to lower the firewall security level using the router administration screen.
The Web site describes the items in the DVTool control panel (Figure 1) in detail.
Figure 1. DVTool-2.0-beta5 Control Panel
On a standard 22" screen with 120 DPI, the panel is 7.1" wide and 6.1" high. The green PTT button at the bottom is 0.2" high.
Figure 2 shows one of the alternate color options (Look and Feel tab > Setup tab).
Figure 2. A high contrast color theme.
The Windows version of DVTool automatically opens a second window with log reports for problem solving. The text is white on black background.
Figure 3. Full screen view with zoom magnification in Ubuntu.
None of the screen readers I tested worked with DVTool 2.0: JAWS and NVDA Reader for Windows, Orca Reader with Ubuntu Linux, and Voice Over on Mac OS X.
Using a DV Dongle
Each time DVTool opens, it downloads a list of hundreds of VHF/UHF repeaters and reflectors in the worldwide D-STAR network. In the Setup tab you can add selections from the list to a Favorites window where they are easier to find. A small checkbox in the Connection tab window displays Favorites in the pull-down menu of gateways.
Unlike a D-STAR radio, DVTools has no channel memories to program. You select a repeater or reflector from a list in the Connection tab and click on "Connect to Gateway."
The Push-to-Talk button at the bottom of the panel can be locked (via a small checkbox beside the button) so one click starts a transmission and a second click ends it.
During monitoring, DVTool displays the call sign of the transmitting station.
Comparisons with Radios
Here are other ways that a DV Dongle differs from D-STAR radios:
• Voice only. No GPS or other separate data transmission.
• Always connects through a repeater or reflector. No simplex.
• Works at locations where there is no local repeater and
locations where the repeater has no Internet gateway.
• Can connect directly to a distant repeater/reflector without
tying up a local repeater.
• No selective incoming or outgoing calls. D-STAR radios can
address to a specific station call sign, and can use
digital call sign squelch to monitor for incoming calls
addressed to your call sign.
• Some D-STAR repeaters do not connect to DV Dongles.
A DV Dongle can provide D-STAR access for low-vision hams who can use a computer screen with magnification software.
Peter DeNeef, AE7PD, is an Extra class amateur radio operator in the U.S. Email: HamRadioAndVision "at" gmail "dot" com.