What tools do I need for basic RF troubleshooting in the lab?

The tools needed for basic RF troubleshooting in the lab provide the ability to generate, measure, and analyze RF signals across the frequency range and power level of the circuits under test. The essential tools are: spectrum analyzer (the single most important RF troubleshooting tool; displays the frequency content of a signal, showing: the fundamental signal, harmonics, spurious signals, noise floor, and oscillation; frequency range: should cover the operating frequency and at least the 3rd harmonic; modern bench analyzers cover 9 kHz to 3-26 GHz; key specification: phase noise (determines the ability to measure close-in noise), dynamic range (determines the ability to see small signals near large ones), and RBW (resolution bandwidth) range), signal generator (provides the test signal for injecting into the circuit under test; frequency range matching the system's operating band; output power adjustable from approximately -120 to +10 dBm; low phase noise for receiver testing; modulation capability (AM, FM, PM, pulse) for testing modulated signal handling), vector network analyzer (VNA) (measures S-parameters (S11, S21, S12, S22) of the circuit or component; essential for: measuring impedance match (return loss), gain (insertion gain/loss), isolation, and filter response; 2-port VNA is minimum; 4-port VNA enables differential and balanced measurements), power meter and sensor (measures absolute RF power accurately; sensor types: thermocouple (for average power, -30 to +20 dBm), diode (for low-level power, -70 to +20 dBm), and peak power sensors (for pulsed signals); accuracy: typically ±0.2-0.5 dB, much better than spectrum analyzer amplitude accuracy), and multimeter and oscilloscope (multimeter: for DC bias measurements (voltage, current, resistance); oscilloscope: for observing transients, modulation envelopes, and bias waveforms; a 1 GHz bandwidth oscilloscope with 5 GSa/s can directly observe RF signals up to approximately 500 MHz). Supplementary tools include: near-field probe set (H-field and E-field probes for locating sources of radiation and coupling on a PCB), calibration kit (for VNA calibration at the measurement reference plane), cables, adapters, and attenuators (SMA, N-type; a set of fixed attenuators (3, 6, 10, 20, 30 dB) is essential for adjusting signal levels without changing the measurement setup).