ELECTROMAGNETIC
COMPATIBILITY

EMC (Electromagnetic Compatibility) at brigade scale means fifty-plus drones, eighty-four MANET nodes, fifteen jammers, and ten radars sharing the same electromagnetic space over five hundred square kilometers. Without frequency planning the jammer protecting Strv 122 at 450-1200 MHz interferes with FPV video at 300-450 MHz two hundred meters away. Lisa 26 enforces the frequency plan: MANET below 300 MHz, FPV 300-450 MHz, jammers above 450 MHz, radar at 24 GHz K-band. SDR monitors continuously. Every new device requires EMC verification before integration into the brigade network.

Signal integrity across the full brigade spectrum requires continuous monitoring and automated management. The separation strategy ensures each system operates in its designated band without crosstalk. Verification before deployment catches configuration errors that would otherwise manifest as unexplained communication failures during operations — failures that are indistinguishable from enemy jamming and waste critical troubleshooting time.

Interference Scenarios and Solutions

The most dangerous EMC failure in a drone brigade: a vehicle-mounted FSG-J2 jammer operating at 450-600 MHz creates broadband noise that bleeds into the FPV video downlink band (300-450 MHz) through intermodulation products in the jammer amplifier. An FPV drone 200 meters from the jammer experiences video breakup — the pilot loses visual reference and crashes. This failure looks identical to enemy jamming, and the drone team spends 30 minutes troubleshooting before realizing their own vehicle caused it.

Prevention: strict frequency separation enforced by Lisa 26. All MANET mesh communications operate below 300 MHz. FPV video uses 300-450 MHz. Jammers operate above 450 MHz with bandpass filters that suppress out-of-band emissions by at least 40 dB. Each new device added to the brigade network undergoes EMC verification: SDR spectrum scan with the device active confirms no interference with existing systems. This takes 15 minutes per device — a small investment compared to the hours wasted troubleshooting phantom jamming from friendly sources.

Testing Procedure

EMC test protocol before every brigade deployment: all electronic systems simultaneously active including MANET mesh, FPV links, jammers, radars, and Lisa 26 terminals. SDR captures baseline spectrogram. Each system is then cycled off individually while SDR records the change. If removing a system reduces interference on another system's band, the two are in conflict. Lisa 26 recommends frequency reallocation to eliminate the conflict. The entire test takes 45 minutes for a battalion-sized deployment and must be repeated whenever new equipment is added or existing equipment is reconfigured.

Frequency Plan Enforcement

Lisa 26 enforces the frequency plan programmatically: each MANET radio receives its assigned frequency band and channel set via encrypted configuration push. FPV transmitters are pre-programmed to their designated band before issue to pilots. Jammers have hardware bandpass filters that physically prevent out-of-band emission — even if software configuration is wrong, the filter blocks transmission below the assigned band. This defense-in-depth approach (software assignment plus hardware filtering) ensures that a misconfigured device cannot disrupt the entire brigade network. The EMC plan is reviewed and updated at every brigade deployment, accounting for new equipment, changed operational area, and lessons learned from previous EMC incidents.

← Del av Fhss Implementation

EMC Frequency Separation Strategy

Electromagnetic compatibility at brigade scale requires strict frequency separation between communication, jamming, and radar systems. The EMC plan assigns MANET mesh communications to 140-300 MHz, FPV video to 300-450 MHz, active jamming to 450-1200 MHz and 2.4/5.8 GHz, and radar to the 24 GHz K-band. This separation ensures that no friendly system interferes with another. Lisa 26 enforces the EMC plan automatically, reassigning frequencies when conflicts are detected.

EMC Testing Before Deployment

Every brigade deployment begins with an EMC verification: all systems activated simultaneously while SDR stations monitor for mutual interference. If a jammer at 450 MHz bleeds into the FPV band at 445 MHz, Lisa 26 shifts FPV channels above the interference zone. EMC testing is not a one-time event — it repeats whenever new equipment joins the brigade network. A single misconfigured jammer can disable MANET across an entire battalion sector.

Implementation

# EMC Frequency Plan — Brigade-Wide Deconfliction
EMC_PLAN = {
    "band_allocation": {
        "140-300 MHz": {
            "assigned_to": "MANET mesh (Silvus StreamCaster)",
            "mode": "FHSS adaptive",
            "max_nodes": 84,
            "power_dbm": 33
        },
        "300-450 MHz": {
            "assigned_to": "FPV video downlink",
            "mode": "Analog FM",
            "max_simultaneous": 15,
            "power_dbm": 25
        },
        "450-1200 MHz": {
            "assigned_to": "FSG-J jammers ONLY",
            "mode": "Broadband noise",
            "note": "NEVER overlap with MANET or FPV bands",
            "power_dbm": 40
        },
        "2.4 GHz": {
            "assigned_to": "FSG-J jammers (DJI/consumer band)",
            "mode": "Targeted",
            "power_dbm": 30
        },
        "5.8 GHz": {
            "assigned_to": "FSG-J jammers (digital FPV band)",
            "mode": "Targeted",
            "power_dbm": 30
        },
        "24 GHz": {
            "assigned_to": "RSP-72 radar",
            "mode": "FMCW",
            "note": "Separate K-band, no interference with comms",
            "power_dbm": 20
        }
    },
    "rule": "Jammer bands ABOVE 450 MHz. Comms bands BELOW 450 MHz. Never overlap.",
    "test_procedure": "Before deployment: all devices ON simultaneously, SDR measures crosstalk"
}

import json
print(json.dumps(EMC_PLAN, indent=2))

Related Chapters

Sources

Normative sources. MIL-STD-461G — US military EMC test standard (public). Frequency regulation — Post- och telestyrelsen (PTS). ICAO/ETSI radio standards for GPS L1 (1575.42 MHz), EU ISM (863–870 MHz), and Ku band (10.7–12.7 GHz). NATO STANAG 4609 Ed. 4 (motion imagery), 4671 (airworthiness) and 2022 (intel evaluation) for military frequency allocation.

Parameter sources. Band plan (MANET 140–300 MHz, FPV 300–450 MHz, jammers 450–1200 MHz, radar 24 GHz) is an FSG-A design framework based on typical military allocation. Silvus StreamCaster characteristics (33 dBm power in FHSS mode) — Silvus published data. RTL-SDR €25 — retail price. The recommended 5 MHz separation is standard radio-engineering practice for narrowband transmissions.

Operational estimates — not validated by FSG-A in the field. 15 minutes per device EMC verification and 45 minutes for a full battalion test are procedure design estimates, not measured with a stopwatch. 40 dB out-of-band suppression is a typical bandpass-filter specification, not tested by FSG-A on real hardware. Compass calibration deviation > 5° as an EMC-problem threshold is an engineering estimate based on ArduPilot documentation, not statistically validated. The MIL-STD-461G claim for Silvus is a manufacturer public specification, not independently verified by FSG-A.

External standards and references. ArduPilot documentation. Silvus Technologies. NATO STANAG 4609 Ed. 4 (motion imagery metadata), STANAG 4671 (UAV airworthiness), and STANAG 2022 (intelligence source reliability). Ukrainian operational experience as documented by Watling & Reynolds, RUSI (2023) and ISW daily assessments (ISW, RUSI public analysis). Swedish Armed Forces public publications (specific documents cited in sections above where applicable). Silvus StreamCaster frequency plan. FSG-A has not performed a brigade EMC test — procedure is conceptual.