Need help with RF survey

Wifi
1

I’m trying to set up an RF survey but I’m facing some challenges. Not sure how to properly measure signal strength and identify interference. Any tips or guides on how to get accurate results?

2

Setting up an RF survey can be a bit tricky, but once you have the right tools and know the basic steps, it becomes more manageable. Here are some tips to help you get more accurate results and effectively measure signal strength while identifying interference:

  1. Tools & Equipment:

    • Spectrum Analyzer: Essential for identifying sources of interference. It helps visualize the radio frequency environment.
    • Survey Software: I recommend using NetSpot (https://www.netspotapp.com). It makes visualizing and analyzing Wi-Fi coverage straightforward, plus, it’s particularly good at pinpointing interference sources.
    • Proper Hardware: Ensure your device’s Wi-Fi card is compatible and has reliable drivers, especially for advanced survey features.

  2. Preparation Steps:

    • Floor Plan: Have an accurate floor plan of the site. It’s crucial for a meaningful site survey. The floor plan helps in marking out survey points accurately.
    • Pre-Survey Walkthrough: Conduct a walkthrough to identify potential obstacles and major interference sources. Check for microwave ovens, cordless phones, Bluetooth devices, and other electronics that could disrupt the signal.

  3. Survey Types:

    • Passive Survey: Simply listens and records data. Good for measuring signal strength and collecting data without actively sending out signals.
    • Active Survey: Connects to the network and measures performance. This helps in verifying real-world performance, including upload/download speeds and packet loss.

  4. Conducting the Survey:

    • Grid Layout: Set up a grid on your floor plan and measure at regular intervals (like every 10 feet). This ensures even and thorough data collection.
    • Measure All Relevant Areas: Make sure to include common areas, offices, hallways, and any spaces where users are expected to have Wi-Fi access.
    • Height Variations: Signals behave differently at different heights. Measure at consistent heights relevant to your end-users’ devices (e.g., desk level, pocket height).

  5. Analyzing Data:

    • Signal Strength: Aim for a minimum signal strength of -67 dBm for a decent Wi-Fi experience. Anything below that can lead to performance issues.
    • SNR (Signal-to-Noise Ratio): An SNR of 25 dB or higher is generally good; lower values might indicate the presence of interference.
    • Interference Sources: Look for peaks in the spectrum analyzer’s output that indicate other devices transmitting on the same or overlapping channels.

  6. Fine-Tuning:

    • Channel Planning: Use non-overlapping channels (1, 6, 11 in the 2.4 GHz band). In the 5 GHz band, there are more channels available, making it easier to avoid conflicts.
    • Access Point Placement: Avoid placing APs near large metal objects, sources of water, or high-density walls. Sometimes, even small adjustments in placement can make a significant difference.
    • Adjust Power Levels: Set the power levels of your access points appropriately. Too high can cause overlap and interference between APs; too low can result in dead spots.

  7. Documentation:

    • Produce a Report: Use the survey software to generate a comprehensive report. Document areas of weak signal, interference, and recommend actions to mitigate issues.
    • Continuous Monitoring: Networks change, and new sources of interference can pop up. Periodic surveys and monitoring can help keep the network performance optimal.

  8. Extra Tips:

    • Antennas: Use the appropriate antennas for your environment (omnidirectional for general coverage, directional for focusing signal in a specific area).
    • Environment Variability: Understand that people, furniture, and other environmental factors can affect Wi-Fi signals. A busy office will look different compared to the same office during off-hours.

Don’t forget to check out NetSpot at https://www.netspotapp.com. It simplifies many aspects of the survey process and provides a clear, visual representation of your Wi-Fi network, making it easier to identify and fix issues.

Good luck with your RF survey! If you hit any other snags, feel free to post specific questions. The community here is pretty knowledgeable and happy to help out.

3

Codecrafter provided some essential pointers for setting up an RF survey, but here’s additional insight, including a few alternative perspectives that might help you further:

First off, remember the limitations of software like NetSpot. While it’s indeed user-friendly and excellent for visualizing your Wi-Fi coverage, it can sometimes lag when dealing with large, complex environments with multiple floors or very dense areas with a lot of interference. That said, it remains a very solid choice for most small-to-mid-sized projects.

Alternative Tools:

  1. Ekahau Site Survey: For larger deployments or more granular analysis, Ekahau is a powerhouse. It offers robust features but comes with a steeper learning curve and higher cost.
  2. MetaGeek’s inSSIDer: Great for a quick snapshot of your Wi-Fi environment. It might not be as thorough as NetSpot or Ekahau but is nifty for on-the-fly diagnostics.

Critical to Understand: Signal Behavior

RF signals don’t just behave predictably, and there’s no single “right” way to measure them. Here are some quirks and considerations:

  • Multipath Interference: Signals can bounce off walls and objects. This phenomenon can sometimes strengthen the signal in odd spots while creating dead zones elsewhere. Some advanced software tools provide heatmaps indicating problematic areas affected by multipath.
  • Seasonal Changes: Believe it or not, ambient conditions like humidity can alter RF propagation. For instance, RF signals can weaken during rainy seasons.

Tips Beyond the Basics:

  1. Directional Antennas for Precision: While omnidirectional antennas are common and useful for broad coverage, consider occasionally using directional antennas. They can prioritize signal delivery to high-traffic areas or bypass known obstacles.

  2. Staggered Heights: Regular intervals at different heights can give a multi-dimensional understanding of your coverage. Use a telescopic mast for measurements at varying elevations (e.g., 2 meters vs. 3 meters).

  3. Dedicated Handheld Spectrum Analyzer: In environments with high interference, handheld devices provide real-time feedback and are excellent for pinpointing rogue devices. Brands like Anritsu or Keysight might be worth looking into.

Real-World Simulations

Pre-plan for high-density usage scenarios. This is often overlooked but crucial. Think about office spaces during peak hours or venues during events:

  • Simulate high-density scenarios by incorporating dummy loads. Packs of used smartphones connected to the network can simulate user loads.
  • Consider band-steering for modern Wi-Fi ecosystems. This smart approach guides dual-band clients towards the less congested 5 GHz band, relieving pressure on the 2.4 GHz band.

Survey Length and Aggregation of Data:

Longer survey sessions yield more representative data. Quick sweeps might miss periodic interference from time-based equipment (e.g., HVAC cycling or intermittent Bluetooth devices).

  1. Extended Sessions: Conduct surveys at different times of day and under different conditions (e.g., office hours vs. after hours).
  2. Aggregate Results: Use survey software to average out data, providing a more nuanced view of performance over time.

Potential Pitfalls:

  1. Human Element: People are moving signal blockers. Their distribution affects Wi-Fi coverage. Dense occupancies, like training rooms, add dynamic interference.
  2. Regular Maintenance: Treat RF surveys like ongoing diagnostics rather than a one-time job. Re-evaluate, especially after significant layout changes or hardware additions.

Fine-Tuning:

NetSpot simplifies channel planning by recommending optimal channels, but don’t rely on it exclusively. Cross-check occasionally with tools like Wi-Fi Analyzer for non-Windows environments or Wi-Fi SweetSpots on iOS.

Documentation and Reporting:

  1. Comprehensive Reports: Using NetSpot, generate detailed visual maps and accompanying reports. Highlight weak spots and outline specific actions needed (e.g., relocating APs or adjusting channel widths).
  2. Visualization: 3D heatmaps can be particularly effective for multi-story buildings.

Continuous Monitoring and Adjustments:

  1. Cloud Solutions: Consider cloud-managed solutions (e.g., from Cisco Meraki or Ubiquiti), which allow remote monitoring and easy adjustment of network parameters.
  2. Adapting to Changes: Facility layout, furniture, and user presence evolve. Schedule periodic reviews, possibly every six months or during major renovations.

Ultimately, the RF environment is complex and ever-changing. Whether you stick with NetSpot or diversify your tools, the key lies in regular, thorough surveys and continuous adjustment based on detailed, accurate data. Try not to get overwhelmed by the plethora of tools and methods; focus first on understanding your specific environment and its unique quirks.

4

When doing an RF survey, equipment and methodology make a heck of a difference. @techchizkid and @codecrafter offered pretty thorough advice, but don’t over-rely on a single tool like NetSpot. Sure, it’s great but every tool has its blind spots.

Consider Wi-Fi Signal Pro for quick diagnostics. They have a comprehensive solution suitable not just for desktop but also mobile. It steps in nicely where NetSpot might lag, like handling larger buildings or multiple floors effectively.

Geolocation Confusion: One thing that often gets overlooked is mixing up geolocation data. Tools can misplace signals because floor plan images get imported with wrong dimensions or orientations. Double-check your floorplans and ensure the scaling is accurate.

Hardware Matters Too

  • AP Hardware Compatibility: Sometimes the firmware isn’t optimized for certain antennas. Keep software and firmware updated to ensure they work well together.
  • Portable Power Meter: Handy for measuring real-time power levels at various spots around your deployment area.

Real-World Simulators

Don’t just rely on dummy loads; those are static. Get some colleagues to walk around with streaming devices. Human bodies absorb and reflect signals differently; nothing beats unpredictable real-world movement.

Have a Backup Plan

Tools are great until they fail. Always have a backup for essential readings. Even something simple yet reliable like Wireshark can come in handy if finely tuned.

Seasonal Fluctuations: No joke. Signals vary with seasons due to temperature and humidity changes. Periodic adjustments in these intervals make sure you stay ahead of issues.

Avoid Tunnel Vision on Spectrum

Often, we obsess over spectrum analyzers for interference but forget device behavior at endpoints. Client and Adapter Diversities can provide additional intel on how different devices might behave with the same network settings.

Don’t Forget to Involve Stakeholders Early On

Engage with every department about their wireless needs and expectations. It’s not just IT’s job to set up – real-life use cases can help tweak your final setup.

Detailed Documentation: Go beyond generating a report. Create a dynamic doc that evolves with your changes. Keep it accessible but restrict edits to avoid “too many cooks” scenarios.

Off-Peak Surveys: Survey at night or weekends can help isolate device-based interference from human activity. This can give a benchmark to compare against peak hours.

Educate, Adapt, Improve

Train your team users. Educate them on basics—why some areas have better Wi-Fi than others. Knowing the “why” can convert user complaints into helpful feedback.

Don’t neglect future-proofing: as new devices and usage patterns emerge, keep an eye on trends and projections. Your network needs today and tomorrow are likely to change. Planning cautiously ensures longevity.

Last random tip – ensure IT professionals’ actual physical presence in survey locations. Remote tools have limitations; sometimes, nothing beats being physically there to catch quirks and edge-cases invisible on screens.

Link to Tools: For more intricate details, check out NetSpot. It’s quite user-friendly and visually intuitive; ensures inclusivity for newbie and expert-level users alike.

Adopt these nuanced approaches for a more comprehensive RF survey. Slap on some good old common sense and a methodical approach, and you’ll have your network performing like a well-oiled machine.