GPS antennas

[Casper]

Ok, I recently purchase the Garmin GPS18 package. It comes with an antenna and the mapping software. So far I like it, but I do have one problem with it. The antenna seams to loose signal quite often. It recovers quickly, but if I am trying to create a track log while it does this it ends up starting a new one.

So my question is this, is there any better antennas out there that will not loose the signal as often, and if so are they able to be hooked up through a USB conection? Thanks again for any help you can offer.

Casper