How to Locate Last-Mile Interference

+ FieldFox Handheld Microwave Analyzer

Hunting last-mile interference using manual triangulation

Determining the location of an unknown signal source requires advanced direction-finding (DF) techniques. When locating last-mile interference, manual signal triangulation is an effective DF method. The process focuses on a sequential measurement approach of signal reception, phase difference, angle calculation, line of bearing, and intersection point. Initially, the DF antenna and receiver gauge the signal reception, capturing the signal’s strength as the antenna sweeps manually through various orientations. The strongest signal direction indicates the peak power and helps determine the phase difference. Derive the angle calculation using the antenna’s alignment relative to the signal’s peak power, rotating the antenna and noting the direction of the strongest signal reception. Establish the signal’s azimuth by aligning the peak reception with a known reference point, typically true north.

Measuring the peak power, azimuth, and geographical position for manual signal triangulation requires a robust test system. The test system includes a single high-gain directional antenna, an RF receiver capable of discerning signal strength and phase, and a GPS device to provide precise location data. The operator moves to different locations, recording the azimuth and GPS coordinates at each point. Then the operator programmatically calculates the angle and combines it with the receiver’s geoposition to establish the line of bearing, which represents the projected path of the signal from the receiver back to its source. The intersection point of multiple mapped bearings pinpoints the signal source. This process integrates with a mapping system for a visual representation triangulating the unknown signal interference.

Last-mile interference-finding solution

Locating last-mile interfering signals requires advanced DF techniques. Perform manual signal triangulation using the Keysight 85574A direction-finding antenna paired with the Keysight FieldFox handheld analyzer. This versatile handheld wideband antenna (20 MHz to 8.5 GHz) integrates seamlessly with the FieldFox spectrum analyzer, which features interference-finding and GPS capabilities for precise and efficient interference location. The 85574A’s compact design includes multiple antennas and a low-noise amplifier for enhanced sensitivity, with a passive mode for strong signal environments. GPS integration enables accurate pinpointing of interference by overlaying trajectory lines on a map. Optional modules extend its frequency range, making it a comprehensive, robust, and user-friendly solution for network maintenance.

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