In The Shop: Old School Radios vs. New School GPS Systems
May 25, 2011
I'm no expert in all aspects of GPS/autosteer/RTK and other high-tech on-board systems, but I've heard through the grapevine that FM business band radios can sometimes cause strange, hard-to-diagnose problems. Those of you who have, uh, "tweaked" your business band radios to get extra coverage may notice more problems than folks running strictly according to FCC rules, but even legal radios can sometimes interfere with GPS-based systems.
If your GPS systems are doing strange things, take note if the problems occur when you key your radio mike. Maybe try turning off the machine so the GPS system reboots, then turn it back on with the FM radio turned off. If the GPS system works okay with the radio off, you'll need to figure out how to shield your GPS system from the electronic emission the radio emits.
Some folks have found that replacing their FM radio's antenna coaxial cable with high-quality shielded cable cures the problem. Others have used a magnetic antenna mount for the FM radio to position that antenna as far as possible from the GPS receiver---on the back of combine grain tanks, on the back end of spray tanks on self-propelled sprayers, on the rear fenders of 4WD tractors.
When you have reception or tracking problems with a GPS system, notice if the problem correlates with the use of any electronic equipment in your cab. Be sure to mention that correlation when you talk with your local GPS specialist/technician. It will help him pinpoint the specific cause of interference, and he can help you figure out how to shield or isolate your GPS system from the electronic interference.