The GPS antenna provided by Flex Radio Systems for their GPSDO add-on module is an indoor-style "biscuit" measuring about 1 x 2 inches. It comes with an adhesive patch that is meant to secure it to an indoor window.
My available window had a rather marginal sky view, and the GPS was not locking up very well. So before going out for a "professional" outdoor antenna, it seemed a good idea to try the one on hand.
Having achieved a certain age, I have a lot of containers for medical prescriptions that I've been saving for some reason. One of the larger ones nicely fits the biscuit, along with some bubble wrap as a filler. The cap used to seal the contents quite well, and it does so even after being sliced to allow the RG-174/U style coax to pass through. (The coax is permanently attached to the antenna.)
Long story short -- the antenna and "radome" attaches to a convenient metal mast about 5 feet off the ground, facing upward. The duct tape system won't last forever, but it's fine for a temporary setup. GPS reception is now quite solid.
It has survived a recent "bomb cyclone" wind and rain event that downed a fair number of trees in our area.