And Happy New Year
A couple of examples of commercial patches for the GPS L1 frequency:
Many of these commercial patches sub-perform, mostly because the design engineer will not read or implement the manufacturers instructions, especially regarding ground plane and weather protection dielectrics.
But sometimes these patches simply have not even been designed for RHCP: there are also models on the market, where dual frequency operation is claimed, one patch direction is tuned for one spot frequency and the orthogonal direction for the other.
Obviosly both are linearly polarized with the -3dB loss penalty.
But happily we mere radio amateurs are smarter