PI 4100 Medium Wave Field Strength Meter

520 kHz to 5.1 MHz
A third generation of precision survery instrumentation for direct measurement of the electromagnetic field strength.

The PI-4100 was designed to become the successor to the industry standard FIM- 41 and to provide the accuracy and reliability that the international engineering community, government regulators, and broadcast licensees have depended on for more than a generation.

PI 4100 innovations include:

  • 127 dB dynamic range measuring receiver
  • Digitally synthesized tuning in 1.0 kHz increments
  • Spectrum Display to facilitate various compliance measurements (Field Strength, Harmonic level, and Spectrum Occupancy) in a single instrument
  • Provisions for third party calibration, using their own laboratory standards, when it is impractical to return the instrument to the manufacturer for calibration
  • Data acquisition software and PC interface to enable the collection, analysis, and e-distribution of field measurements. (This feature anticipates the future acceptance of data e-filing by federal regulatory agencies.)

Various I/O ports have been provided to enhance the versatility of the instrument and to perform certain operational tasks such as battery recharge and computer data exchange.

The PI 4100 is Potomac’s third generation of precision survey instrumentation intended for the direct measurement of electromagnetic field strength in the 520 kHz to 5.1 MHz frequency spectrum. This instrument combines a laboratory quality radio frequency voltmeter, a calibrated, Balanced Loop antenna, an internal GPS receiver, an internal calibration source, and data acquisition hardware and software in a single rugged package weighing less than 3 kg.

This device is equipped with an embedded microcontroller engine that obtains measurement data from the various transducers within the instrument and formats that data for display and, at the option of the use, stores it to memory.

    • Lightweight, Rugged & Portable
    • Accurate & Versatile
    • Self Calibrating & Easy to Operate
    • Digital Tuning
    • Digital Field Strength Display
    • Digital Spectrum Display
    • Digital Data Capture & Storage
    • SBAS augmented GPS positioning
    • E-Data Friendly Transport Software
    • Useable, 200 kHz – 8500 kHz
    • DRM Capable
    • Harmonics Measured to 5.1 MHz
    • Uncalibrated FS to 600 V/m
    • Antenna Orientation Compass
    • Use Hand-held or Tripod mount
    • Calibration Traceable to: NIST *
    • External 50 ohm Calibration Input Port
    • RF Output for external Spectrum analyzer
    • DC Output of dBuV/m
    • Removeable Loop Antenna
    • Shielded Modular Construction
    • Built-in Quality and Reliability by: Potomac Instruments, inc.

* US National Institute of Standards and Technology

 Field Strength Meter
 Frequency Range 520 kHz to 5.1 MHz, calibrated
 Field Strength Range 22 µV/M to 50 V/M (27 dBuV/m)
to 154 dBuV/m)
 Measurement Uncertainty 3.0% (±0.3 dB) referenced to NIST*, standard field
Measurement Bandwidth
Adjacent Channel Rejection
Image Rejection
Spurious Rejection
1.0 kHz
>85 dB at ±9 kHz
>60 dB
>80 dB
 Minimum Frequency Step 1.0 kHz
 Self generated 2nd &
3rd harmonics
<-85 dBc (carrier F/S <10 V/M,
from 530 to 1700 kHz)
 Antenna Type Balanced, multiturn Loop (removeable)
 RF Voltmeter
 Electrical specifications
shown above
RF Signal is applied directly to RF In BNC
 Measurement Units µV-mV-V; mV only; dBuV/m
Spectrum Display
 Center Frequency Range 520 kHz to 5.1 MHz
 Frequency Span ±63 kHz, ±22 kHz
 Resolution Bandwidth 1 kHz
 Data Storage & Retrieval
 Measurement Points 250 max.
 Download Software PI Proprietary (Microsoft Excel®
format compatible)
 Download Format ASCII: Comma Delimited
 I/O Ports
 Headphone Jack 3.5 mm Stereo Audio Jack
 Battery Charging Jack
(12-15 Vdc)
2.1 mm Power Jack (Switchcraft 722A
or equiv.)
 Data output / Control Input   Jack USB Type B (for bi-directional computer interface)
 Jack BNC (provides for calibration by a
3rd party cal. lab.)
 External RF Input Jack BNC (input impedance 1890 ohm +12pF) provides for antenna
signal injection
 External RF Output Jack BNC (50 ohms) RF output is proportional
to Field Strength
 Batteries (AA cells, six   required) Rechargeable; NiMH (supplied)
(can also use 1.5V: Alkaline or Lithium)
 Battery Life 5 Hrs. Minimum before Recharge (NiMH)
 Battery Recharge Time 3 to 4 Hours
 Operating Temperature
Range °C(°F)
-15°C to +50°C (+5°F to +130°F)
 Dimensions cm (inches) 38x18x28 cm (15x7x11 in.)
 Weight kg (lbs.) 2.5 (5.5)

* Specifications subject to change without notice.