LRS Secretary Andy Sinclair MM0FMF gave a comprehensive talk about GPS - Global Positioning System - and its applications in Amateur Radio including SOTA - Summits On The Air at the LRS meeting on Wednesday 9th November 2011. Andy described the origins of GPS, and how it manages to to provide users with both their location and a highly accurate time reference. He also described the sources of errors and how these can be mitigated. He concluded with descriptions of the updates coming to GPS starting soon. Several GPS receivers and associated units were shown (photographs below).



Andy Sinclair MM0FMF presenting his GPS talk to the LRS.

 

 

 

 Nice GPS satellites graphic from  http://www.gps.gov/ (site worth visiting).

Aisin GPS receiver of 1998 vintage sold on the surplus market for $20.

 

Aisin active patch antenna for $20 GPS receiver above.

 

Trimble Palisade 1pps (pulse per second) time source.

 

Mid-2000's Garmin eTrex Vista HCX mapping GPS receiver suitable for walkers and SOTA - Summits On The Air.

 

Vaisala GPS-sonde Wind Profiler. Of particular interest is the beautiful little Quadrifilar Bi-Helix antenna with omni-directional circularly-polarized hemispherical pattern.