Research shows a lightbar can pay for itself in three years on only 300 acres. It can be done with a GPS receiver that receives the free WAAS correction signal that functions within 12-inch accuracy.

This was just one precision farming economic message presented by Matt Darr, Iowa State University ag engineer, during a field day at its Northern Research Farm field day, according to a story in AgriNews.

“This is suitable for non-critical guidance, including tillage, spraying and seeding/drilling,” Darr said. “They are also used for autoswath systems on sprayers, but accuracy will decline in larger fields.”

Investing in a $2,000 light bar for a sprayer can cut chemical costs by 4 to 8 percent per year, Darr said. In areas with rugged terrain, the savings have been as much as 17 percent.

Dual frequency correction offers advances over single frequency correction and provides pass-to-pass accuracy within 4-inches or better, Darr said. This works well for precise auto steering for planting and for planter section control. It requires a yearly subscription that can range from $800 to $1,500.

Real Time Kenematic, or RTK, correction is the most accurate GPS correction because it uses a privately-owned reference station located close to the GPS receiver. RTK can provide one-inch pass-to-pass accuracy and is the only GPS correction that provides year-to-year position stability. RTK allows controlled traffic, strip tillage/fertilization/planting and extremely precise autosteering. Darr said that although RTK receiver costs have come down, the investment is still high from a cost and complexity standpoint.

RTK networks maintained by groups of implement dealers are available for a subscription fee. The cost is similar to a dual frequency subscription.

Read the story to learn more about more network choices and their value.