📶 Why Mobile Signal Shows Negative Numbers (dBm) — Ideal Range for Stable Internet
Summary: Mobile signal strength is measured in dBm. The closer the number is to zero, the stronger your signal. Example: -60 dBm = strong, -100 dBm = weak. Learn why it’s negative, what’s ideal for 4G/5G, and how to improve it.
What is dBm?
dBm means decibel-milliwatts. It’s a measure of signal power. Mobile tower signals are much weaker than 1 milliwatt, which is why their values appear negative like -75 dBm or -90 dBm.
Signal Strength Chart
| Signal (dBm) | Quality | Meaning |
|---|---|---|
| -50 to -70 | Excellent | Very strong signal, stable internet |
| -71 to -85 | Good | Normal browsing and clear calls |
| -86 to -100 | Weak | Slow speed, possible call drops |
| -101 to -120 | Very Weak | No service or poor coverage |
Why Are Values Negative?
Because mobile signals are much weaker than 1 milliwatt. In decibel scale, anything below 1 mW becomes negative. So -60 dBm is stronger than -90 dBm.
How to Check Signal Strength
- Go to Settings → About Phone → SIM Status → Signal Strength.
- Or dial *#*#4636#*#* and select “Phone Information”.
- You’ll see something like -79 dBm / 28 ASU.
Example: -79 dBm Signal
| Parameter | Value | Meaning |
|---|---|---|
| Signal Strength | -79 dBm | Good and stable connection |
| Speed Expectation | 10–40 Mbps | Normal browsing and streaming |
| Call Quality | Clear | Low drop chances |
Ideal Ranges for Stable Internet
| Use Case | Recommended dBm | Result |
|---|---|---|
| 5G Internet | -60 to -80 | Ultra-fast & stable |
| 4G/LTE | -70 to -90 | Good speed & reliability |
| Video Calls | -80 or better | Stable, less lag |
| Gaming | -70 or better | Low ping & smooth |
Tips to Improve Signal
Move near windows
Walls block radio waves. Stay near open space.
Toggle Airplane mode
Refreshes network connection quickly.
Enable Wi-Fi Calling
Use broadband when mobile signal is weak.
Use signal booster
For offices or homes with poor coverage.
Summary Table
| Category | Excellent | Good | Weak |
|---|---|---|---|
| dBm Range | -50 to -70 | -71 to -85 | -86 to -100 |
| Use | Gaming / HD Streaming | Browsing / Calls | Basic texting |