Finding sources of EMI/EMC/RFI emissions problems. Radiating susceptible circuits to find pickup points.Noninvasive probing of RF circuits or PC boards, for example oscillator frequency, sidebands, phase noise.Probes are passive, they require a display instrument (spectrum analyzer, power meter, or oscilloscope) with 50-ohm input impedance to display the power received from the probe.Probes are single-axis so they respond to fields orthogonal to the loop or parallel to the stub. Integrated electrostatic shield in the loop probes eliminates common-mode pickup. Multiple loop sizes offer optimum sensitivity and spatial resolution at different frequencies.Probe dimensions optimized for access to tight spaces.Calibrated sensitivity up to 3 GHz, depending on model. Usable to beyond 6 GHz.Can be driven by a signal source to generate fields for electromagnetic susceptibility testing.Minimum measurable field and resolution depends on your display instrument, and on pre-amplifier (see below). No battery or power supply needed for the probe.The following curves show the measured output power of each probe into 50 ohms for a 1 uT rms field (without pre-amplifier). This can also be computed from the equations below the figures. 
Loop Probes (EMC-100A/B/C): The equation below for Output Power is plotted in the loop probe graph above, and is accurate to within ± 3 dB at frequencies from DC to the 3 dB frequency shown in the table below for each loop probe. The probes are usable to higher frequencies but the sensitivity is uncalibrated above the 3-dB frequency. The first notch in the frequency response of the probes occurs at the first resonance listed in this table. Output Power = [X + 20*log10(B) + 20*log10(F)] dBm Where B is the rms magnetic flux density in Tesla, F is the frequency of the received signal in Megahertz X is a scale factor from the following table: Loop SizeX3-dB Frequency First ResonanceLarge 85.1 50 MHz 500 MHzMedium 67.1 1000 MHz 2600 MHzSmall 44.4 3100 MHz>6000 MHzElectric Field Probe (EMC-100D): Stub probes tend to be less repeatable than shielded loop probes, due to the presence of common-mode currents flowing on the outer surface of the probe or attached cable. As signals are measured, it is common to see a few dB of variation in output power as the user changes their grip on the probe or the attached cable. Because of this, the sensitivity of the 100D is not guaranteed. Typical sensitivity of the Electric Field Probe is given by the following equation, and shown in the 100D figure above.Output Power = [-113.2 + 20*log10(E) + 20*log10(F)] dBmWhere E is the rms electric field strength, in Volts/meterF is the frequency of the received signal in Megahertz Length, excluding connector: 6.35" (161 mm)Tip thickness: 0.11" (2.8 mm) can be inserted into seams and gapsTip diameter: Stated above next to photos. 
