How to Screen for Satellite Interference Before You File with the ITU

A frequency-overlap screening pass is one of the cheapest things you can do early in the filing process — and one of the most commonly skipped, usually because doing it by hand against years of BR IFIC history is tedious enough that it gets postponed until it's someone else's problem.

What "interference screening" actually means at this stage

Before any detailed link-budget or orbital-geometry analysis, the first useful question is much simpler: does any other filed network use a frequency range that overlaps mine, in the same general service? This is a coarse pass — it doesn't account for antenna pointing, actual traffic, or geometric separation — but it's exactly what you need to build a shortlist of networks worth investigating further, out of what can be thousands of unrelated filings.

Two different starting points

How you run this screening depends on where your own filing stands:

• Your filing is already published. You know your own frequency plan and your own publication date. The screening question becomes: which networks published after mine use overlapping frequencies? Those are the ones with a coordination obligation toward you.
• Your filing isn't public yet. You still know your intended frequency plan. Here the useful screening looks backward: which already-published networks would your new filing potentially need to coordinate with once it goes public? Catching this before submission means you walk into the process with a realistic picture of who you'll be talking to.

What to actually check, per candidate network

Once you have a shortlist of frequency-overlapping filings, a handful of fields tell you most of what you need for a first triage:

Field	Why it matters
Administration & notice type	Tells you who you'd be coordinating with, and how formal the current stage is (advance publication vs. coordination request vs. notification).
Frequency range & bandwidth	Confirms the overlap is real and how much of your band it actually touches — a 1 MHz sliver at the edge of a 500 MHz band is a very different conversation than a full overlap.
Polarization	Opposite polarizations can substantially reduce practical interference risk even with full frequency overlap.
EIRP & antenna gain	A rough proxy for how much power is actually likely to land where it could matter.
Orbital parameters (for NGSO) or orbital position (for GSO)	Geometric separation is often the deciding factor — two overlapping bands pointed at completely different parts of the sky may never actually interact.

Why doing this once isn't enough

New filings appear continuously. A screening pass done the week you submit your own filing tells you nothing about a conflicting network published six months later — but that later filing can still trigger a real coordination obligation. Treating this as a one-time check, rather than an ongoing one, is how operators end up surprised by a coordination request they had no visibility into until it landed in their inbox.