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NBAND

Reference

Fourteen bands, and what each one is bad at.

A band is defined by physics, not by which part you bought. Two builders using different thermal cameras contribute to the same band; the discriminator reads what each sensor can actually resolve rather than assuming they are equivalent.

10-14 m10-8 m10-3 m103 m
GammaUltravioletVisibleNear infraredShort-wave infraredLong-wave infraredMillimetre waveRadio frequencyAcoustic and infrasoundSeismic
Off the EM axisMagnetic and ELF/VLFGravimetricEnvironmentalNavigation and pose

The whole argument in one table

What each band can see, and what it cannot

Detection strength for every band against every phenomenon the discriminator models. This is the reason the platform samples more than one band: read down a column and you will find the same object visible in several, which is what makes a coincidence between two of them evidence.
Detection strength of each band for each phenomenon, from 0 (blind) to 3 (strong).
BandAircraftSatelliteBird or insectMeteorLightningSmall droneBalloonExhaust plumeRF emitterGround vehicle
Gamma0000100000
Ultraviolet1002300201
Visible3323323202
Near infrared3212222302
Short-wave infrared3112122302
Long-wave infrared3121121303
Millimetre wave2010031003
Radio frequency3301332031
Magnetic and ELF/VLF1000310012
Acoustic and infrasound3011330003
Seismic1001100002
Gravimetric1000000000
Detection strengthblindmarginalusablestrong

Read the columns, not the rows. Every phenomenon here is visible in several bands, which is why a coincidence between two of them is evidence and a single bright pixel is not. The zeroes matter as much as the threes: gamma is blind to almost everything in this table, and publishing that is more useful than implying otherwise.

Why these bands

The atmosphere picked the list, not us

Sea-level opacity plotted against wavelength, with the sampled bands overlaid. The transparent regions are the optical, infrared, and radio windows. Everywhere else, nothing reaches the ground and no sensor is worth building.
0.01 pm10 pm10 nm1 µm1 mm1 m1000 mopaquetransparent
The band list is not a design choice. It is the set of windows the atmosphere leaves open. Where the curve drops, radiation reaches the ground and a sensor is worth building; where it rises, nothing arrives and no amount of money buys a detection. This is also why the gravimetric, acoustic, and seismic channels exist at all: they carry information through exactly the regions where the electromagnetic spectrum is closed.

Cost of entry

Ranked by what it costs to open the band at all

Cheapest registered part that produces usable data in each band. Three bands cost less than a takeaway meal, and one costs more than a car.
BandEntry costReachPhenomena seenKilled by
Acoustic and infrasound$1312 km4 / 10nothing here
Millimetre wave$15250 m3 / 10nothing here
Ultraviolet$255 km3 / 10cloud, rain, fog, daylight
Radio frequency$40300 km6 / 10nothing here
Magnetic and ELF/VLF$4030 m2 / 10nothing here
Long-wave infrared$758 km5 / 10cloud
Visible$7830 km9 / 10cloud, rain, fog
Seismic$893 km1 / 10nothing here
Near infrared$9620 km8 / 10cloud
Gamma$18930 m0 / 10nothing here
Short-wave infrared$2.4k25 km6 / 10cloud
Gravimetric$150k100 m0 / 10nothing here

Detection bands · 12

Channels that can produce a detection

Ordered by increasing wavelength, which is also the order they appear in the schema and in the database enum. An event needs at least two of these to agree before it can be called unresolved.

Gamma

0.01 pm – 10 pm

Ionizing photons above 100 keV.

Works when

daylightstrong
darknessstrong

Sees through

cloudstrong
rainstrong
fogstrong
smokestrong

Practical reach

30 m

order of magnitude for an aircraft-sized target in good conditions

Cheapest way in

$189

lowest registered part that opens this band

Detectsnothing in the reference set
Blind toAircraftSatelliteBird or insectMeteorSmall droneBalloonExhaust plumeRF emitterGround vehicle

What it picks up

Radioisotope decay, cosmic-ray secondaries, and any source emitting hard photons. The only band in the stack that responds to nuclear rather than thermal or electronic processes.

Where it fails

Counting statistics dominate. A small scintillator sees roughly 20-60 counts per second of background, so a real excursion needs either a large deviation or a long integration. Air attenuates low-energy gammas strongly, which caps useful range at tens of metres for weak sources.

Ultraviolet

100 nm – 400 nm

100 to 400 nanometres, above the violet edge of vision.

Works when

daylightblind
darknessstrong

Sees through

cloudblind
rainblind
fogblind
smokemarginal

Practical reach

5.0 km

order of magnitude for an aircraft-sized target in good conditions

Cheapest way in

$25

lowest registered part that opens this band

DetectsMeteorLightningExhaust plume
Blind toSatelliteBird or insectSmall droneBalloonRF emitter

What it picks up

Corona discharge, electrical arcing, plasma, combustion, and lightning leaders. Solar UV sets the daytime floor, so the band is far more informative after dark.

Where it fails

Ordinary glass blocks most of it, so the sensor needs a quartz or fused-silica window. Atmospheric ozone absorbs hard UV entirely. Daytime dynamic range is brutal: the Sun is roughly six orders of magnitude above any plausible target.

Visible

380 nm – 750 nm

380 to 750 nanometres, the band your eye already covers.

Works when

daylightusable
darknessstrong

Sees through

cloudblind
rainblind
fogblind
smokeblind

Practical reach

30 km

order of magnitude for an aircraft-sized target in good conditions

Cheapest way in

$78

lowest registered part that opens this band

DetectsAircraftSatelliteBird or insectMeteorLightningSmall droneBalloonExhaust plumeGround vehicle
Blind toRF emitter

What it picks up

Anything that reflects sunlight or emits its own light: aircraft, satellites, meteors, balloons, birds, and the occasional thing that fits none of those. Provides the astrometry that turns a detection into a bearing.

Where it fails

Useless through cloud and nearly useless in daylight against a bright sky for dim targets. A single camera gives bearing but never range, which is why NBAND treats single-node visible detections as unresolvable in distance by construction.

Near infrared

750 nm – 1.4 µm

750 to 1400 nanometres, just past the red edge.

Works when

daylightmarginal
darknessstrong

Sees through

cloudblind
rainmarginal
fogmarginal
smokemarginal

Practical reach

20 km

order of magnitude for an aircraft-sized target in good conditions

Cheapest way in

$96

lowest registered part that opens this band

DetectsAircraftSatelliteMeteorLightningSmall droneBalloonExhaust plumeGround vehicle
Blind toRF emitter

What it picks up

Hot exhaust, incandescent surfaces, IR illuminators and rangefinders, and haze-penetrating reflected light. Silicon sensors are natively sensitive here, so removing the IR-cut filter from a normal camera buys the band for free.

Where it fails

Sensitivity falls off a cliff past 1100 nm where silicon stops absorbing. Sunlight is rich in NIR, so daytime contrast is poor. Without a bandpass filter the channel is contaminated by ordinary visible light.

Short-wave infrared

1.4 µm – 3 µm

1.4 to 3 micrometres. Reflective, not thermal.

Works when

daylightusable
darknessstrong

Sees through

cloudblind
rainmarginal
fogusable
smokeusable

Practical reach

25 km

order of magnitude for an aircraft-sized target in good conditions

Cheapest way in

$2.4k

lowest registered part that opens this band

DetectsAircraftMeteorSmall droneBalloonExhaust plumeGround vehicle
Blind toRF emitter

What it picks up

Sees through haze, thin smoke, and some fog far better than visible light. Discriminates materials by reflectance in a way no other band in this stack can. Night-sky airglow illuminates targets passively at 1.5 to 1.7 micrometres.

Where it fails

Requires an InGaAs sensor. This is the single most expensive band per pixel in the platform and the reason tier 3 exists. Water vapour absorption bands carve holes in the spectrum.

Long-wave infrared

8 µm – 14 µm

8 to 14 micrometres. Pure thermal emission.

Works when

daylightstrong
darknessstrong

Sees through

cloudblind
rainmarginal
fogmarginal
smokestrong

Practical reach

8.0 km

order of magnitude for an aircraft-sized target in good conditions

Cheapest way in

$75

lowest registered part that opens this band

DetectsAircraftBird or insectSmall droneExhaust plumeGround vehicle
Blind toRF emitter

What it picks up

Everything warmer than absolute zero, by its own emitted heat rather than reflected light. Works in total darkness and through smoke. A radiometric sensor reports actual temperature per pixel, which turns a track into an energy-budget measurement.

Where it fails

Resolution is low and expensive to increase; 160x120 is the affordable tier. Germanium optics only, which are costly and fragile. Uncooled microbolometers drift, so a shutter-based flat-field correction interrupts the stream every few minutes.

Millimetre wave

3.7 mm – 1.25 cm

24 to 81 gigahertz active radar.

Works when

daylightstrong
darknessstrong

Sees through

cloudstrong
rainmarginal
fogstrong
smokestrong

Practical reach

250 m

order of magnitude for an aircraft-sized target in good conditions

Cheapest way in

$15

lowest registered part that opens this band

DetectsAircraftSmall droneGround vehicle
Blind toSatelliteMeteorLightningExhaust plumeRF emitter

What it picks up

The only band in the stack that measures range and radial velocity directly, by illuminating the target and timing the return. Gives the discriminator a physical distance, which is what converts an angular track into a real trajectory.

Where it fails

Short range for small radar cross-sections: a few hundred metres for a drone-sized target with a hobby module. Rain attenuates heavily. Ground clutter and multipath produce persistent false returns that have to be learned and subtracted per site.

Radio frequency

5 cm – 600 m

500 kilohertz to 6 gigahertz, received passively.

Works when

daylightstrong
darknessstrong

Sees through

cloudstrong
rainstrong
fogstrong
smokestrong

Practical reach

300 km

order of magnitude for an aircraft-sized target in good conditions

Cheapest way in

$40

lowest registered part that opens this band

DetectsAircraftSatelliteLightningSmall droneBalloonRF emitter
Blind toBird or insectExhaust plume

What it picks up

Emissions rather than reflections. Aircraft transponders, satellite downlinks, control links, broadband impulsive noise from discharge events, and anything transmitting where nothing should be. Also feeds passive radar: an aircraft crossing a broadcast transmitter's illumination produces a Doppler-shifted echo.

Where it fails

The spectrum is crowded and every site has a unique interference fingerprint that must be characterised before anything can be called anomalous. A single antenna gives no bearing without a rotator or a coherent multi-receiver array.

Magnetic and ELF/VLF

Hz – 30 kHz

DC to 30 kilohertz field measurement, not photon detection.

Works when

daylightstrong
darknessstrong

Sees through

cloudstrong
rainstrong
fogstrong
smokestrong

Practical reach

30 m

order of magnitude for an aircraft-sized target in good conditions

Cheapest way in

$40

lowest registered part that opens this band

DetectsLightningGround vehicle
Blind toSatelliteBird or insectMeteorBalloonExhaust plume

What it picks up

Static and slowly varying magnetic fields, sferics from distant lightning, power-line harmonics, and any moving ferromagnetic or current-carrying mass close enough to perturb the local field. This is the band that has historically carried the most repeatable anomalous reports.

Where it fails

Falls off as the cube of distance for a dipole source, which makes it a close-range channel: metres to low tens of metres for anything realistic. The Earth's 25 to 65 microtesla background is five orders of magnitude larger than any plausible signal, so everything depends on differential measurement and gradiometry.

Acoustic and infrasound

0.05 Hz – 20 kHz

0.05 hertz to 20 kilohertz pressure waves.

Works when

daylightstrong
darknessstrong

Sees through

cloudstrong
rainmarginal
fogstrong
smokestrong

Practical reach

12 km

order of magnitude for an aircraft-sized target in good conditions

Cheapest way in

$13

lowest registered part that opens this band

DetectsAircraftLightningSmall droneGround vehicle
Blind toSatelliteBalloonExhaust plumeRF emitter

What it picks up

Propeller and rotor signatures, jet noise, sonic booms, and the infrasound tail that survives to long range when audible sound has already been absorbed. Independently corroborates or refutes a claim that an optical track was silent.

Where it fails

Sound arrives seconds after light, so acoustic correlation needs a range estimate to line up. Wind noise dominates infrasound and requires a mechanical wind filter to suppress. Urban sites are close to unusable below 100 hertz.

Seismic

0.01 Hz – 100 Hz

Ground motion from 0.008 to 100 hertz.

Works when

daylightstrong
darknessstrong

Sees through

cloudstrong
rainusable
fogstrong
smokestrong

Practical reach

3.0 km

order of magnitude for an aircraft-sized target in good conditions

Cheapest way in

$89

lowest registered part that opens this band

DetectsGround vehicle
Blind toSatelliteBird or insectSmall droneBalloonExhaust plumeRF emitter

What it picks up

Ground-coupled acoustic energy from low overflights, and, at high-tier sites, the vibration reference a gravimeter needs to separate real gravitational signal from the ground moving underneath it.

Where it fails

Almost entirely a noise-characterisation channel at low tiers. Cultural noise from roads and machinery swamps everything below a few hertz at any site near people.

Gravimetric

—

Absolute local gravitational acceleration.

Works when

daylightstrong
darknessstrong

Sees through

cloudstrong
rainstrong
fogstrong
smokestrong

Practical reach

100 m

order of magnitude for an aircraft-sized target in good conditions

Cheapest way in

$150k

lowest registered part that opens this band

Detectsnothing in the reference set
Blind toSatelliteBird or insectMeteorLightningSmall droneBalloonExhaust plumeRF emitterGround vehicle

What it picks up

The only channel that responds to mass-energy directly rather than to photons or fields. A discrepancy between the mass implied by radar cross-section and the mass implied by gravitational perturbation is a measurement no other instrument in the stack can produce.

Where it fails

Research tier only. Atom-interferometer gravimeters cost six figures and need vibration isolation and a co-located seismometer for noise subtraction. A 1000 kilogram object at 50 metres produces roughly 2.7 nanogal, which is at the edge of a portable instrument's single-shot floor and needs matched filtering to recover. Almost every NBAND node will never carry one, and the schema is built so that absence is recorded rather than assumed.

Context bands · 2

Channels that can never produce a detection

These exist so that every detection carries the conditions it was made under. Treating an environmental excursion as a detection is a well-documented failure mode of amateur sensor networks, so the discriminator will not score on these alone, by construction rather than by policy.

Environmental

—

Pressure, temperature, humidity, wind, sky quality, cloud cover.

Works when

daylightstrong
darknessstrong

Sees through

cloudstrong
rainstrong
fogstrong
smokestrong

Practical reach

0 m

order of magnitude for an aircraft-sized target in good conditions

Cheapest way in

$23

lowest registered part that opens this band

Detectsnothing in the reference set
Blind toAircraftSatelliteBird or insectMeteorLightningSmall droneBalloonExhaust plumeRF emitterGround vehicle

What it picks up

Nothing on its own. It exists so that every detection carries the atmospheric state it was made under, which is what allows a refraction artefact, a temperature inversion, or a wet radome to be ruled in or out afterwards rather than argued about.

Where it fails

Not a detection channel. Treating an environmental excursion as a detection is a known failure mode of amateur sensor networks and the discriminator refuses to score on it alone.