A few years ago the Earth experienced the worst solar flare activity in 250 years which caused some GPS receiver installations to temporarily fail. Many worldwide systems depend upon the GPS system, including the timing system used by Cambium networks.
This type of occurrence doesn't generally affect our systems; however here is a list of characteristics seen to impact GPS performance.
1.) Excessive RF loss in the cable run between the GPS antenna and the CMM. This can be due to the use of lossy or damaged coaxial cable. Any reduction of the signal beyond the supplied length of cable will reduce the GPS receiver's capabilities.
2.) The GPS antenna should be positioned in clear view of the sky. Large obstructions (buildings, large antennas, steep ground terrain adjacent to the GPS antenna) will deteriorate the GPS receiver's ability to see many satellites.
3.) Strong transmitters (500-2500MHz) in the beam of the GPS antenna may cause overload in the GPS receiver causing reduced dynamic range (receiver desensitization) in the GPS frequencies. This also inhibits the GPS receiver's reception to the weaker satellites (satellites at low angles to the horizon).
These conditions may cause sporadic loss of timing sync in times when the satellites have impaired signals due to atmospheric conditions. Canopy system operators need to monitor the number of satellites being received, and confirm that number against other GPS radios in their system. GPS radios that regularly see fewer satellites than others in the system may have impaired reception.
For systems experiencing related issues, setting each individual AP (or BH Master) to generate its own timing signal AND enabling the spreading feature will allow Canopy systems to operate without the aid of the diminished capacity GPS system.
To view the current status of the solar activity and expected interference ranges with GPS systems, please visit the Proton Flux Plot on http://www.sec.noaa.gov/nav/gps.html