IoT Guys

📶 Beyond Signal Bars: Understand RSSI, RSRP, RSRQ, SINR – A Friendly Guide for IoT Pros

Mobile Signal Strength

🌍 Introduction: Why Signal Strength Matters

If you’ve ever installed a 4G or 5G router and wondered why you’re not getting the speeds or reliability you expected, you’re not alone. One of the biggest misconceptions in the world of wireless connectivity is that signal bars equal performance. Unfortunately, they don’t. Routers—especially high-performance units like those from Teltonika, Robustel, or InHand Networks—rely on deeper, more technical metrics to determine how well they’re actually connected to the mobile network.

This guide is designed to demystify those metrics: RSSI, RSRP, RSRQ, and SINR. We’ll explain what they are, how they affect performance, and how to interpret them. We’ll also explore what impacts those readings, how antennas make a difference, and give you a complete step-by-step method for testing and improving signal quality.

Whether you’re an installer working on an industrial IoT deployment or a business owner setting up a mobile office, this guide will help you make sense of what your router is really telling you.


🤔 Understanding the Metrics: What Do They Mean?

Before diving into hardware and antennas, let’s explore what each of these signal strength metrics represents. They all tell part of the story of your wireless link.

🔹 RSSI: Received Signal Strength Indicator

What it is: RSSI measures the total signal power received by your router, including both useful LTE signal and unwanted noise or interference. It’s like measuring the total noise level in a room, whether people are talking or shouting or there’s a TV blaring.

Typical Range:

  • Excellent: > –70 dBm
  • Average: –70 to –90 dBm
  • Poor: < –90 dBm

🔹 RSRP: Reference Signal Received Power

What it is: RSRP is a more accurate measure of LTE signal quality. It calculates the average power level of reference signals broadcast by the cell tower.

Typical Range:

  • Excellent: > –80 dBm
  • Good: –80 to –95 dBm
  • Weak: < –100 dBm

🔹 RSRQ: Reference Signal Received Quality

What it is: RSRQ gives insight into how clean your signal is. It compares the RSRP (useful signal) to RSSI (total signal).

Typical Range:

  • Excellent: > –10 dB
  • Acceptable: –10 to –15 dB
  • Poor: < –15 dB

🔹 SINR: Signal-to-Interference-and-Noise Ratio

What it is: Perhaps the most critical metric of all, SINR tells you how clearly your router can “hear” the tower above the surrounding noise.

Typical Range:

  • Excellent: > 20 dB
  • Fair: 10–20 dB
  • Unusable: < 0 dB

❌ Why Signal Bars Can Be Misleading

Signal bars are a simplified visual representation. Most routers base them on RSSI alone, which is affected by everything from noise to device sensitivity. Always trust the metrics, not the bars.


đź§­ How to Access These Metrics

For Teltonika routers:

  1. Log into the WebUI
  2. Navigate to Status > Network > Mobile Information
  3. Look for RSRP, RSRQ, SINR, Band, and Cell ID
  4. Optionally use RMS, AT Commands, or SNMP for remote logging

🏗️ Real-World Signal Example (Teltonika RUTX50)

Site A: Indoors in server rack

  • RSRP: –106 dBm | RSRQ: –18 dB | SINR: 2 dB → Unstable connection

Site B: Window-mounted

  • RSRP: –93 dBm | RSRQ: –11 dB | SINR: 10 dB → Moderate

Site C: External antenna on roof

  • RSRP: –81 dBm | RSRQ: –8 dB | SINR: 21 dB → Stable & fast

📡 Antennas: Not Signal Boosters, But Smart Repositioning Tools

🔍 Common Misunderstanding

External antennas are not signal boosters. They don’t amplify signal strength; they simply relocate the point of signal capture to a more optimal location. That could be the roof of a building, a pole above tree lines, or simply outside a metal cabinet or vehicle where signal is stronger and less obstructed.

đź§  Understanding dBi Gain

Antenna gain, measured in dBi, describes how focused the antenna’s signal pattern is:

  • Lower gain (2–5 dBi) antennas offer broader coverage, useful in mobile setups.
  • Higher gain (8–12 dBi) antennas are more focused and reach farther, but must be aimed.
  • More gain doesn’t always mean better—it depends on distance to the tower and surrounding obstructions.

Types of Antennas and Real Use Cases

Antenna TypeBest Use CaseExamples / Notes
Stubby Blade AntennasStandard installs3–5 dBi peak gain, included with most routers. Good indoors near windows.
Omni-directionalVehicles, uncertain tower locationReceives from all directions. Moderate gain. Great for transport and urban areas.
Directional (Yagi/LPDA)Rural, remote fixed sitesMust be aimed precisely. Higher gain. Use only if necessary.
Wall/Pole Mount PanelGeneral building exterior useE.g., Fullband MIMORAD (2×2), Panorama DWMM4-6-60 (4×4 MIMO for 5G).
Dome / Cabinet AntennasCabinets, towers, limited spaceE.g., Fullband FB4x4MIMO dome. Designed for durability, not just gain.
Embedded Micro AntennasManholes, underground gatewaysTiny, low-gain, but suited to confined environments.

đź§­ Choosing Antennas by Application

  • Industrial cabinet? Use a rugged dome antenna.
  • Wall of warehouse? Use a MIMORAD panel.
  • Vehicle? Go omni-directional with low profile.
  • Rural CCTV mast? Directional Yagi with line of sight.
  • Manhole smart sensor? Use embedded low-profile micro antenna.

Every environment has a matching antenna—not based on dBi alone, but on practical design and installation constraints.


đź§Ş How to Field Test Signal

  1. Power off router
  2. Move to likely strong signal location (e.g., window, roof)
  3. Power on and wait for reconnection
  4. Log RSRP, RSRQ, SINR, Band
  5. Repeat for multiple spots
  6. Install antenna in location that performed best

đź“‹ Keep a Signal Log

Log everything:

  • Date/Time
  • Location (indoors, loft, wall, cabinet, roof)
  • RSRP / RSRQ / SINR
  • LTE Band / Cell ID
  • Speedtest or real throughput
  • Antenna type used

This allows for future tuning and troubleshooting, especially across multiple deployments.


âť“ Frequently Asked Questions

Q: What’s the best signal strength value to monitor?

  • A: SINR is the most useful for throughput. Combine it with RSRP for full clarity.

Q: Should I aim for the highest dBi antenna?

  • A: Not necessarily. Higher dBi is more focused and needs precise alignment. Match the antenna to your environment.

Q: My router has 4 bars but my video buffers—why?

  • A: Bars often reflect RSSI, not SINR or RSRQ. Check all metrics.

Q: Do antennas boost the signal?

  • A: No. They relocate the point of signal reception to a less obstructed, cleaner environment.

Q: Can one antenna work for all cases?

  • A: No. Antennas are designed for specific use cases—consider location, signal strength, mounting, and application.

đź’Ş Final Thoughts

Don’t just install and hope for the best. Treat every 4G/5G router deployment as a site-specific job. Use the metrics. Test multiple locations. Choose antennas based on practicality and environment—not marketing claims. And remember:

âś… RSSI tells you total signal (not just the good bits)
âś… RSRP tells you how loud the tower is
âś… RSRQ tells you how clean the line is
âś… SINR tells you how clearly your router hears the tower

Understanding these—and pairing them with the right antenna strategy—is how you get rock-solid LTE/5G performance.

Comments

    Leave a Reply

    Your email address will not be published. Required fields are marked *