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title: Kuidas Meshtastic signaalimõõtur töötab

parent: User Guide

nav_order: 15

last_updated: 2026-06-25

description: How the signal meter rates quality from SNR relative to the LoRa modem preset — spread spectrum, presets, and what the bars really mean.

aliases:

• signal

• signal-meter

• snr

• rssi

The Meshtastic signal meter — the familiar bars or status color in the app — is calculated very differently than the "bars" on a traditional cell phone or WiFi router.

Most consumer devices simply measure how "loud" a signal is. Kuna Meshtastic kasutab LoRa (Long Range) tehnoloogiat, mõõdab selle signaalimõõtja signaali selgust võrreldes sinu võrgu konkreetsete sätetega.

Every time the LoRa radio chip receives a message, it reports two measurements:

• RSSI (Received Signal Strength Indicator): The loudness of the raw power hitting your antenna.

• SNR (Signal-to-Noise Ratio): The clarity of the signal compared to the background static.

│ 💡 Tip: Here's an analogy — imagine you are trying to hear a friend talking to you. - RSSI is how

│ loud their voice is. - The Noise Floor is the background noise in the room (air conditioning,

│ other people talking, traffic). - SNR is how easily you can distinguish your friend's voice from

│ the background noise.

Kui su sõber karjub sulle kõrvulukustava rokkkontserdi ajal, on signaal uskumatult vali (kõrge RSSI), aga sa ei saa temast ikkagi aru, sest taustamüra on valjem (halb signaali-müra suhe). Conversely, if your friend whispers to you in a dead-silent library, the signal is very weak (Low RSSI), but you can understand them perfectly (Great SNR).

For standard radios (like FM or WiFi), if the background noise is louder than the signal (a negative SNR), the receiver just hears static.

LoRa is special. It uses "Spread Spectrum" modulation, which allows the radio to mathematically pull a signal out of the air even when it is buried deep underneath the background noise. Seepärast näed Meshtasticus sageli negatiivseid SNR numbreid (nt -10 dB, mis tähendab, et signaal on 10 detsibelli nõrgem kui taustamüra).

Sõltuvalt sellest, millist Meshtastic eelhäälestust kasutad (nt T383838PikkKauge vs. T383838LühikeKiire), on raadiol kindel SNR-i piirang – absoluutne maksimaalne müra hulk, mida see talub enne, kui sõnum staatilise müra tõttu täielikult kaob.

The app rates your signal quality (None, Bad, Fair, or Good) from SNR alone, measured relative to the preset's SNR Limit — the demodulation floor described above. It deliberately does not factor RSSI into the rating: without the local noise floor, RSSI cannot tell you whether a signal is actually decodable, so SNR-versus-the-preset-limit is the meaningful measure. (RSSI is still displayed to you elsewhere.)

Because the rating is relative to the preset limit, the same SNR can rate differently on different presets — T383838-15 dB is healthy on T383838LongSlow but unusable on T383838ShortFast. Letting T383838limit be the active preset's SNR Limit, here is how the app picks the bars (or color):

│ Note: The fixed SNR thresholds you may have seen elsewhere (T383838-7 dB / T383838-15 dB) are now only used for

│ coloring individual hops in traceroute results — not for the per-node signal meter described

│ here.

Kuna Meshtasticu mõõdik toimib "selguse mõõturina", käitub see erinevalt sellest, mida enamik inimesi ootab:

│ 💡 Tip: Don't panic over low RSSI. You might see a seemingly terrible RSSI value like T383838-118 dBm.

│ On a cell phone, you would have zero bars. Aga kui sinu seadme signaali-müra suhe on T383838+2 dB,

│ näitab Meshtastic ikkagi tugevat signaali! The library is quiet, so the whisper is heard

│ ⚠️ Warning: Watch out for local noise. If you hook up a massive antenna and see a great RSSI

│ (e.g., T383838-90 dBm) but your signal meter is only showing 1 Bar (Bad), you have a problem. It means

│ you have local interference — perhaps a cheap power supply, a noisy computer, or a nearby radio

│ tower — creating so much static that it is drowning out your mesh.

In the app, signal data is shown in several places:

• Node list — signal bars icon next to each node

• Node detail — SNR, RSSI, and signal quality in the device metrics section

• Traceroute — per-hop signal quality for each relay node

• Signal metrics — historical SNR and RSSI data in the metrics charts

!Node entry showing SNR, RSSI values and colored signal bars

• Nodes — where signal bars appear in the node list

• Node Metrics — SNR/RSSI history and the per-node signal quality reference

• Settings — Radio & User — modem presets and their SNR limits