Most of the current Garmin models can work with remote antennas such as the ones made for autos and boats. They are relatively low profile and would also work as an external backpack antenna...or mount it to a hat
Some of the older model Garmins (GPS II, III, V) have a removable antenna and a patch cable used to be available to turn it into a remote antenna.
Some of the older model Garmins (GPS II, III, V) have a removable antenna and a patch cable used to be available to turn it into a remote antenna.