How does the Clearinghouse determine when a cost-sharing obligation has been triggered?
The Proximity Threshold Test (PTB) is the test the Clearinghouse uses to determine cost sharing obligations. The true benefit to the PTB is that it does not require extensive engineering studies or analyses and it yields consistent, predictable results without the variations common with the use of TIA TSB 10F standards. The FCC recognized that the Proximity Threshold Box also limits a licensees ability to engineer around relocated facilities to avoid reimbursement obligations. They concluded that the use of such a bright-line test in this context will ease the burden of administering cost sharing rules. Additionally, it should encourage new entrants in the AWS to relocate incumbent licensees in the first instance. The length of the Proximity Threshold rectangle shall be X, where X is a line extending through both nodes of the microwave link to a distance of 48 kilometers (30 miles) beyond each node. The width of the rectangle shall be Y, where Y is a line perpendicular to X and extendi
