Analyzing the RF Environment
An essential element in RF network planning is the analysis of spectrum usage and the strength of the signals that occupy the spectrum you are planning to use. Regardless of how you measure and log or chart the results you find (through the Spectrum Analyzer in SM feature or by using a spectrum analyzer), you must do so:
- At various times of day.
- On various days of the week.
- Periodically into the future.
As new RF neighbors move in or consumer devices in your spectrum proliferate, this will keep you aware of the dynamic possibilities for interference with your network. Mapping RF Neighbor Frequencies These modules allow you to:
- Use a SM or an AP as a spectrum analyzer.
- View a graphical display that shows power level in RSSI and dBm at 5 MHz increments throughout the frequency band range, regardless of limited selections in the Custom Radio Frequency Scan Selection List parameter of the SM.
- Select an AP channel that minimizes interference from other RF equipment.
CAUTION - The following procedure causes the SM to drop any active RF link. If a link is dropped when the spectrum analysis begins, the link can be re-established when either a 15-minute interval has elapsed or the spectrum analyzer feature is disabled.
Analyzing the spectrum
To use the built-in spectrum analyzer functionality of the Radio, proceed as follows:
1 Predetermine a power source and interface that works for the SM in the area you want to analyze.
2 If possible, power down all the APs in the area,
3 Take the SM and interface device to the area.
4 Access the Tools web page of the SM.
5 Click Start Timed Spectrum Analysis
6 After 10 seconds, results are displayed:
Travel to another location in the area.
7 Click Start Timed Spectrum Analysis
8 Repeat Steps 6 and 7 until the area has been adequately scanned and logged.
As with any other data that pertains to your business, a decision today to put the data into a retrievable database may grow in value to you over time. The Spectrum Analyzer contains configurable parameters to fit your business requirements. Refer the PMP 450 Operations Guide for more information.
NOTE: Wherever you find the measured noise level is greater than the sensitivity of the radio that you plan to deploy, use the noise level (rather than the link budget) for your link feasibility calculations.