The Navman F20 is well designed and attractive, with a charcoal-gray case. The unit is easily swapped between cars, as it's a compact 3.1 inches high by 4.5 inches wide by 0.9 inch thick, and weighs just 7.1 ounces. Navman kept external controls simple: to the right of the screen sits a Main Menu button and a navigation key that, when pressed repeatedly, cycles through various screens--3D map view, next turn, turn-by-turn directions, and route summary. We also liked the Gas and Parking buttons, which retrieve a list of the closest gas stations and parking garages. The power button is located on the top of the unit, with volume controls on the unit's right side--a touch we always appreciate, as external buttons save us the trouble of digging through multiple screen menus. Oddly, these buttons looked a bit crooked on our review unit, but they still worked fine.
There are no tricks or gimmicks with the Navman F20--the company set out to create a basic, easy-to-use navigation system, and that's what it is. The SiRFstarIII GPS receiver is integrated into the device, and all maps are preloaded on the unit's 2GB Secure Digital card--so all you have to do is insert it into the Navman F20's expansion slot and you're ready to go. When you first turn on the Navman F20, you'll answer a number of setup questions, such as selecting a regional map and whether you want the unit to display miles or kilometers. This process is straightforward and fairly quick.
The Navman F20 offers 2D- and 3D-map views, as well as day and night modes. In the 3D screen mode, the Navman F20 displays information such as: the current street and the name of the next street on your chosen route; direction and distance to the next turn; GPS status; a zoom button; and an information icon. When you press this button, the unit launches a page that displays the remaining distance to the destination, estimated time of arrival, the current time, your current speed, direction, and the unit's remaining battery life. The Navman F20 also can display text-based instructions, and has screens dedicated to showing the route's next turn and the route summary. Of course, all of this information is supplemented by voice prompts. The Navman F20 does not support text-to-speech functionality, however, so you'll only get generic instructions (for example, turn left in 100 feet) rather than specific street names.
The Navman F20 includes a comprehensive points-of-interest database that contains all the basics (gas stations, hotels, ATMs) as well as more specialized categories (amusement parks, concert halls, monuments). Some of the listings were out of date, however. For example, we searched for restaurants and bars in a San Francisco neighborhood, and discovered several listings had gone out of business.
We tested the Navman F20 in San Francisco. From a cold start, it took the unit about 3 minutes to acquire a GPS fix; subsequent starts were much faster. The Navman F20 accurately tracked our position as we drove around the city. We also entered a specific destination, and the Navman F20 quickly returned with a suggested route. We found the directions accurate, and the unit was quick to recalculate our route when we veered off track. That said, we had a hard time hearing the voice prompts, even with the volume up to its highest level. The F20 is rated for up to 3.5 hours of battery life.