I was tired of not getting the best GPS reception based on the location of my TomTom 920 so I broke down and bought the external antenna. I purchased it from mountguys.com for $14.95. Part code: MCX-TomTom710. The next challenge was to find a place where the antenna would be effective but hidden. Some folks at Smart Car of America had a great idea of hiding it under the a/c console cover. This modification took a whole 20 minutes to complete. Just remove the cover like you were going to install the radio, place on top with velcro, feed wire down below or wherever you need it and then you are done.
Now you see it… Now you don’t! Reception even works well inside my garage.