Automated frequency pair generation
Scans every valid TX and RX combination inside the configured ranges and split, then filters for guard band compliance and existing channel collisions before scoring.
Frequency Coordination
Frequency Coordination Tool
Find clean, interference free TX and RX frequency pairs with full intermodulation analysis for surface and underground radio systems.
Overview
Frequency coordination is the engineering process of selecting transmit and receive frequency pairs that will not generate harmful intermodulation products in the band of interest. Done badly, it produces in band spurs that mask weak signals, drive trunked systems into hunting, and trigger persistent intermittent interference that is notoriously difficult to diagnose once the network is in service.
The noIM₃ Frequency Coordination Tool runs an exhaustive search across user defined TX and RX frequency ranges, applies split, guard band, and exclusion zone constraints, then scores every candidate pair against ITU standard 2nd, 3rd, and 5th order intermodulation models. Results are ranked so the cleanest, lowest risk pairs surface first, making the tool suitable for both greenfield deployments and incremental channel expansion within a working network.
Surface mode evaluates the full ITU 2nd, 3rd, and 5th order product set typical of open air radio deployments. Underground mode focuses on 3rd order dominance, which reflects the confined environment behaviour observed in mining, tunnelling, and metro radio systems where higher order products are heavily attenuated by structure loss.
Capabilities
ITU standard intermodulation engine
2nd, 3rd, and 5th order product analysis on every candidate. Surface mode reports the full set. Underground mode focuses on 3rd order dominance for confined environments.
Ranked pair scoring
Each pair receives a composite score combining intermodulation hit count, minimum separation, and spectral cleanliness, so the cleanest options surface at the top of the list.
Guard bands and exclusion zones
Enforces engineering and licensing constraints. Guard bands, exclusion ranges, and protection of incumbent channels are applied at search time, not as an afterthought filter.
Interactive spectrum visualisation
Carriers and intermodulation products overlaid on the band, so you can validate coordination outcomes visually before committing to a channel plan.
Manual frequency entry
Pin specific TX or RX frequencies (for example fixed dispatch channels) and let the tool coordinate the remainder of the plan around them.
Standards & methodology
- ITU SM.1446. Intermodulation interference reference
- ITU SM.337. Frequency separation between adjacent transmissions
- ITU SM.329. Unwanted emissions in the spurious domain
- ACMA spectrum management framework alignment for Australian deployments
When to use this tool
- Selecting clean frequency pairs for new radio system deployment
- Expanding an existing trunked or conventional network without introducing self interference
- Designing underground communication systems in mining and tunnelling environments
- Predeployment engineering validation for mission critical and life safety networks
- Generating coordinated channel sets for contractors and field technicians
- Producing spectrum interaction visualisations for engineering reports and licence applications
- Coordinating frequency plans for emergency services and resource sector radio fleets
- Validating vendor proposed channel plans before purchase or rollout
- Diagnosing in band interference issues on operational networks
- Planning channel reuse strategies across multi site deployments
- Supporting ACMA licence applications with documented coordination output
- Coordinating fleetwide channel changes during band restructures or refarming activity
Is this the right tool for you?
Reach for the Frequency Coordination Tool in any of the following situations.
- You are deploying a new radio system and need to choose TX and RX frequencies that will not generate harmful intermodulation products in your operating band.
- You are expanding an existing trunked or conventional radio network and need additional channels that do not interfere with the channels already in service.
- You are designing a leaky feeder or radiating cable system in a mine or tunnel and need underground appropriate frequency pair selection.
- You are responsible for spectrum coordination across a contractor radio fleet and need a single coordinated channel set that everyone can use.
- You are seeing intermittent in band interference on a working network and want to verify whether your existing channel plan is actually intermodulation clean.
- You need to produce a spectrum coordination report for a regulator, customer, or internal stakeholder, with a clear audit trail of how each pair was chosen.
- You have fixed dispatch or repeater channels that cannot move and you need the remainder of the plan coordinated around them.
- You are evaluating several candidate bands and want a quick side by side comparison of which band yields the cleanest pair set under your constraints.
- You are validating a frequency plan proposed by a vendor or contractor and want an independent second opinion before signoff.
- You are training new RF engineers and need a teaching tool that surfaces intermodulation outcomes visually rather than as opaque numerical output.
- You are coordinating an emergency services network where in band spurs are a safety risk and clean pair selection is non negotiable.
- You are preparing an ACMA licence application and need defensible engineering output to support the channel choices on the form.
Frequently asked questions
What is frequency coordination and why does it matter?
Frequency coordination is the process of choosing TX and RX frequency pairs that do not generate harmful intermodulation products inside the band of interest. Without it, a system will produce in band spurs that mask weak signals and cause intermittent interference that is very difficult to diagnose once the network is in service.
Which intermodulation orders does the tool evaluate?
Surface mode evaluates 2nd, 3rd, and 5th order products following the ITU SM.1446 framework. Underground mode focuses on 3rd order dominance, which reflects the confined environment propagation observed in mining and tunnel radio systems where higher orders are heavily attenuated by structure loss.
How is each frequency pair scored?
Each candidate pair is scored on a composite of intermodulation hit count weighted by order, minimum separation between carriers and intermodulation products, and spectral cleanliness across the working band. Higher scores indicate cleaner, lower risk pairs and surface first in the ranked output.
Can I protect existing channels and exclusion zones?
Yes. The constraint engine enforces user defined existing channels, guard bands, and exclusion ranges (for example licensed incumbents or broadcast bands) at search time. Pairs that would violate any constraint are eliminated before scoring rather than filtered after the fact.
Does it support manual frequency entry?
Yes. You can pin specific TX or RX frequencies, for example fixed dispatch or repeater channels that cannot move, and the tool will coordinate the remaining channels around them.
Is the tool suitable for underground or mine radio coordination?
Yes. The underground mode is calibrated for confined environments where 3rd order intermodulation dominates and higher order products are heavily attenuated by structure loss. This avoids the false positives that a full surface mode analysis would produce in tunnels and stopes.
Does the tool align with ACMA spectrum management practice?
Yes. The coordination output is structured to support ACMA licence applications and Australian spectrum management workflows, with traceable input parameters, ranked candidate output, and exportable spectrum diagrams suitable for inclusion in engineering submissions.
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