The engineering math nobody wants to do by hand.

Third and fifth order products against your site frequency list, so interference turns up on paper rather than in a complaint. The list builds itself: click a tower and every licensed land mobile frequency loads from FCC data, along with the FM and TV stations on the site, because a 100 kW FM carrier is usually the strongest mixer on the tower and ULS cannot see it. Receive inputs are derived by band offset and labeled as convention, never guessed, and the report shows which frequencies came from where.

The study a frequency coordinator runs before anyone files: does the proposed base station clear every incumbent the rules protect? Pick the license at a site and its frequency, power and heights load as filed, or enter a new station by hand. The study applies the FCC rule for the band: the 800 and 900 MHz separation table with the contour pair it came from, the forward and reciprocal adjacent-channel analyses on the 800 MHz interstitial channels with the interference levels the rule tabulates by emission, and the VHF and UHF service-versus-interference contour test. Contours are drawn on the FCC's own propagation curves at the height above average terrain of every radial, incumbents come from the ULS copy, and the result names each station that passes, fails, or needs a letter of concurrence, with the map and a letterheaded report to attach to the request.

Two pre-construction screens apply before a tower goes up, and the second is the one shops miss. FAA screening answers whether the FAA needs notice. AM protection answers whether a nearby broadcast station does: within a wavelength of a nondirectional station and over 60 electrical degrees tall, or within the lesser of ten wavelengths or three kilometers of a directional one and over 36. Notice is due 30 days before construction, and both screens run off the same coordinates against live FCC data.

Two things a co-located site needs that one transmitter at a time will never tell you. RF exposure summed across every emitter on the tower, each against its own frequency limit, because sources that pass alone can be over the line together. And a desense budget: transmitter noise landing in the receive channel, front-end blocking, the receiver's thermal floor, and how many dB of isolation the site is short. Both work from your measured numbers.

Zone radius, the 60% clearance rule, earth bulge, and the diffraction cost of that ridge or tree line near the path.

Fade margin to edge and area coverage percentages, receiver noise floor, sensitivity conversions, RF exposure per OET-65, VSWR, and ERP.

Ground rod resistance from soil and rod dimensions, and antenna-to-antenna isolation from vertical or horizontal separation for repeater planning.

Coax loss by cable type and run length, dBm/watts/microvolt conversions, PL and DPL tone tables, emission designator decoding, audio line levels, DC voltage-drop, and battery runtime.