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    Part Number or Numbers

    Monitoring Loops

    Schwarzbeck Monitoring Loops

    • FESP 5133-7/41 – Circular Shielded Loop Sensor
     FESP 5133-9 – Circular Screened Coil

     ADD FESP 5133-F – Circular shielded loop sensor

    • REMOVE FESP 5133-1330 – Circular Coil

     FESP 5134-1 – Field Monitoring Loop

    • FESP 5134-40 – Loop Sensor / Antenna

    • ADD FESP 5134-40 Option LoopHolder50


    FESP 5133-7/41 

    Schwarzbeck FESP 133-7_41 Circular Shielded Loop Sensor 

    · Circular shielded loop sensor to determine the magnetic field strength

    · 36 turns AWG 7/41

    · diameter 133 mm

    · distance gauge 7 cm included

    · MIL 461E RE101 or RS101 alternative test procedures.


    pdficon small Data Sheet FESP 5133-7/41


    FESP 5133-9 – Circular screened Coil 

    FESP 5133-9 - Circular screened Coil

    The magnetic, handheld coil FESP 5133 was designed to generate defined magnetic field strength in the audio frequency range up to 3 MHz.

    The main application is immunity testing against magnetic fields according to VG 95377 Part 13 and many others. Depending on the current source characteristics magnetic fields up to 400 A/m can be generated for a short time. There are further rings available on request in order to provide a certain scaling between coil current and magnetic field strength (e.g. 1 Amp coil current = 10 A/m field strength).

    Application as magnetic field probe: The FESP 5133-9 can also be used to measure existing magnetic fields. The open circuit output voltage is directly proportional to the magnetic field strength (at fixed frequency) or directly proportional to frequency (at constant magnetic field strength).

    Number of turns: 9
    Wire diameter: 1.2 mm Cu
    Maximum coil current: 11 A (5 min.)
    Nominal coil current: 7 A continuous
    Max. magn. field strength: 380.4 A/m (5 min.)
    Nominal magn. field strength: 242 A/m continuous
    Magnetic field strength, 1 A coilcurrent: (with 50 mm distance ring): 34.58 A/m
    Current required for 1 A/m:
    (with 50 mm distance ring)
    28.9 mA
    Flux density with 50 mA at 50 mm distance: 127 dBpT
    Inner coil diameter: 133 mm
    Medium coil diameter: 134.2 mm
    Spacing coil center to measurement plane: 50 mm
    Mechanical dimensions:  0.16 m x 0.2 m
    Connector: N-jack
    Usable frequency range: 10 kHz – 3 MHz
    Inductance: ~ 20 μH
    Resistance: 0.1 Ω
    Weight: 0.8 kg
    Standard: VG 95377 Part 13


     Schwarzbeck FESP 5133-9 Circular Screened Coil Data Sheet


    FESP 5133-F – Circular shielded loop sensor 

    The Loop Sensor FESP 5133-F was designed to monitor the generated magnetic fields in radiated susceptibility tests. There is nearly no difference to the FESP 5133-7/41, which was originally designed for MIL-STD461E and previous versions, in which the RF-litz wire type AWG 7/41 was specified. Recent versions of MIL-STD461 F and G require a resistance between 5 Ω to 10 Ω for the loop sensor instead. This new requirement was met by the use of a suitable RF-litz wire, which provides a resistance of 7.2 Ω for the FESP 5133-F.


    Number of turns: 36
    Medium coil diameter: 133 mm
    Usable Freqency Range: 0.01 kHz – 200 kHz
    Resonance Frequency: ~700 kHz
    Inductance: ~330 µH
    Resistance: 7.2 +/- 1 Ω
    Capacitance: ~157 pF
    Weight: 220 g
    Mechanical Dimensions: 136 x 177 x 36 mm
    Mount: 3/8″
    Terminals: BNC
    Standards: MIL-STD-461F


     Schwarzbeck FESP-5133-F Field Monitoring Coil Data Sheet


    REMOVE!!!!! FESP 5133-1330 – Circular Coil 

    The handheld coil FESP 5133-1330 was designed for immunity testing against magnetic fields up to approx. 20 kHz. The coil has 225 turns of Cu-wire on 15 layers. There are spacers to provide a constant distance of 50 mm between coil center and EUT-surface. The generated magnetic fieldstrength is direct proportional to the coil current. Typical Applications are Immunity Tests according to the Measuring Method SF 01 G acc. to VG 95377 standard.


    Medium coil diameter: 126 mm
    Medium Coil Distance to Surface: 50 mm
    Number of turns: 225
    Wire Diameter: 2 mm
    Mechanical Dimensions: 190 x 190 x 290 mm
    Terminals: 4 mm Laborstecker
    Usable Frequency Range: 0 – 20 (50) kHz
    Inductance: 6.5 mH
    Resistance: 0.5 Ω
    Capacitance: 240-300 pF
    Resonance Frequency: 120 kHz
    Impedance: |Z|=42 Ω @ 1 kHz
    Max. Current: 20 A
    Max. Fieldstrength at 50 mmspacing: 17 kA/m
    Max. magnetic fieldstrength at 1 A coil current in 50 mm distance: 858.2 A/m
    Required Current for 1000 A/m in 50 mm distance: 1.165 A
    Magnetic Flux Density at 1 A coil current in 50 mm distance: 1.078 mT
    180.66 dBpT
    Conversion Current-Magnetic Fielstrength: 58.67 dB/m
    Weight: 5.3 kg
    Standard: Measuring Method SF 01 G acc. to VG95377


     Datasheet FESP 51331330

    FESP 5134-1 

    Schwarzbeck Field Monitoring Loop FESP 5134-1
    The magnetic, handheld field sensor coil FESP 5134-1 was designed to determine the magnetic fieldstrength during immunity tests.
    The loop sensor consists of a single shielded turn and can be used up to 400 MHz. The FESP 5134-1 is intended to be used with 50  measuring equipment, e.g. spectrum analyzers or measuring receivers. Thanks to the shielded turn the loop sensor achieves high symmetry and good E-field rejection.

    Typical applications are immunity tests acc. IEC 61000-4-39, several automotive standards, the measurement of human exposure limits acc. to ICNIRP, IEEE C.95- 2005, 26.BImSchV and many others.




    Number of Turns:


    Coil Diameter:

    40 mm

    Usable Frequency Range:

    10 kHz -400 MHz

    Nominal Frequency Range:

    100 kHz – 300 MHz


    ca. 125 nH


    ca. 70 g


    46 x 18 x 95 mm




    pdficon small Schwarzbeck FESP 5134-1 Data Sheet



    FESP 5134-40 

    Schwarzbeck FESP5134_40 Loop Sensor Antenna 

    · Loop Sensor / Antenna

    · diameter 4 cm

    · 51 turns

    · 0 Hz to 150 kHz

    · electrostatic shielding

    · BNC jack


    pdficon small Data Sheet FESP 5134-40

    Option: LoopHolder50

    Calibration fixture to hold FESP 5134-40 in FESP 5132 in a distance of 50 mm acc. MIL461E figure RS101-3.