POTOMAC INSTRUMENTS INC. PI 4100 User manual

PI 4100
Medium-Wave Field Strength Meter
User’s Guide

The following items are included with the original packing:
The PI 4100
PI 4100 User’s Guide
CD including PI 4100 Data Downloader software, 4100 Data Report
Template1software, and the PI4100 Field Calibration Data Sheet
Operator’s Quick Reference Guide
Charging power supply and power cord
Charging cable for vehicle use
USB A to B Cable
Battery holder for six AA cells
About the packing material:
Save the box and foam insert for use when returning the PI 4100 for calibration or
repair. See the User's Guide or www.pi-usa.com for return procedures.
Note that the foam inserts will fit exactly into the PELICAN® 1610 CASE for transport
and storage. This case is available from a number of suppliers that can be reached
via the internet.

PI 4100 Medium Wave Field Strength Meter
User’s Guide
Operating and Service Instructions
Version E, Universal
15 January 2014
Potomac Instruments inc,
7309 Grove Road, Unit D, Frederick, MD 21704, USA

Table of Contents
1. General Description .............................................................................................. 6
1.1 Overview .................................................................................................. 6
1.2 PI 4100 Key Feature ................................................................................ 7
1.3 Specifications ........................................................................................... 8
2. Receipt and Inspection .......................................................................................... 11
2.1 Unpacking ................................................................................................ 11
2.2 Reshipment to factory .............................................................................. 11
2.3 Service and Warranty for Equipment and Accessories ............................ 11
2.4 Factory contact information…………………………………………….. 11
3. Controls, Indicators, and External Ports ............................................................ 12
3.1 Front Panel ................................................................................................ 12
3.2 Primary Display Screen Elements ............................................................ 14
3.3 Rear Panel Signal and Power Ports ........................................................... 15
4. Operation ................................................................................................................ 16
4.1 First-Time Operation ................................................................................ 16
4.2 PI 4100 Operating Procedure Details ....................................................... 18
4.2.1 Setting the operating frequency ................................................ 18
4.2.1.1 Turn-on frequency ……............……………………. 18
4.2.1.2 MENU-Tx select ...………………………………… 18
4.2.1.3 FREQ PRESET ……………………………………. 18
4.2.1.4 FREQ SET ...……………………………………… 18
4.2.1.5 Harmonics …………………………………………. 18
4.2.2 Entering and changing station data for GPS use ....................... 18
4.2.2.1 Enter station data using MENU – Tx add..……….. 19
4.2.2.2 Enter station data using Data Downloader ………… 19
4.2.2.3 Change existing station data: MENU – Tx edit…… 19
4.2.3 Self-calibration, automatic and manual ..................................... 20
4.2.4 Saving Measurements: SAVE and HOLD ................................ 20
4.2.4.1 Starting a save …….……………………………….. 20
4.2.4.2 Completing the save ……………………………….. 21
4.2.4.3 Entering Save screen data before measuring ………. 21
4.2.4.4 The HOLD key …………………………………….. 21
4.2.4.5 View and delete saved data ………………………... 21
4.2.5 Measuring Field Strength .......................................................... 21
4.2.5.1 Field strength units ………………………………… 21
4.2.5.1 Loop antenna orientation …………………………... 21
4.2.5.3 LPF use…………………………………………….. 21
4.2.5.4 DC field strength output …………………………… 22
4.2.5.5 Temperature effects ………………………………... 22

4.2.5 Measuring Field Strength, cont’d
4.2.5.6 Measuring pure DRM transmissions ………………. 22
4.2.5.7 Measuring HD Radioall-digital transmissions…… 22
4.2.5.8 Low measuring limit ….……………………………. 22
4.2.5.9 High measuring limit ……………………………….. 22
4.2.5.10 Frequency range for measurements ……………….. 23
4.2.6 Measuring Harmonics ................................................................ 23
4.2.6.1 Measurement conditions ……………………………. 23
4.2.6.2 Measurement procedure …………………………….. 23
4.2.7 Spectrum mode operation .......................................................... 23
4.2.8 Measuring RF voltage: the RF In BNC jack ............................. 24
4.2.9 RF Out BNC jack use.................................................................. 24
4.3 Menu Operation Reference ........................................................................ 25
4.3.1 Menu Navigation………………………………………………. 25
4.3.2 Menu Item Description………………………………………… 25
4.4 Battery Information .................................................................................... 27
4.4.1 Charging the battery ................................................................... 27
4.4.2 Loose-cell battery ....................................................................... 27
4.5 Data storage and retrieval: The PI 4100 Data Downloader program .......... 28
4.5.1 General ......................................................................................... 28
4.5.2 Viewing and deleting data using the PI 4100 controls and
display.......................................................................................... 28
4.5.3 The PI 4100 Data Downloader Program...................................... 28
4.5.4 Data Downloader program installation ....................................... 28
4.5.5 Data Downloader program operation .......................................... 29
4.5.6 Data record fields ........................................................................ 30
5. Service Information ................................................................................................. 31
5.1 Maintenance ............................................................................................... 31
5.2 Troubleshooting and Repair ........................................................................ 31
5.3 Calibration .................................................................................................. 32
5.4 PI 4100 Calibration Verification Test ... ..................................................... 32
5.5 Contact Information .................................................................................... 35
6. Technical Information.............................................................................................. 36
6.1 Introduction ................................................................................................. 36
6.2 PI 4100 Technical Description..................................................................... 36
Appendix 1: Using the magnetic compass of the PI 4100 ............................................. 44
Appendix 2: PI 4100 Operation Quick Reference ......................................................... 46-47
Appendix 3: Sample ExcelField Strength Measurements Report ............................. 48
Appendix 4: PI 4100 Accessories................................................................................... 50

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1. General Description
1.1 Overview
The PI-4100 is Potomac Instruments’ third generation of precision survey instrumentation
designed specifically for the direct measurement of electromagnetic field strength in the 200 kHz to 5.1
MHz frequency spectrum. This microcontroller driven instrument combines a laboratory quality
measuring receiver, a balanced loop antenna, an internal GPS receiver, an internal calibration source, data
acquisition hardware and software, and a graphical LCD display in a single rugged package weighing less
than 3 kg. The device measures, displays, and at the option of the operator, records the following:
Field Strength. This instrument measures and indicates electromagnetic field strength in the 200 kHz to
5.1 MHz spectrum at levels ranging from 30 µV/m (29.5 dBuV/M) to above 50 V/m (154 dBuv/M).
Date & Time of measurement. For logging the PI 4100 indicates date and coordinated universal time
(UTC) derived from the Global Positioning Satellite (GPS) constellation. For users preferring to
record data in local time, the operator has the option of offsetting UTC time via menu selection.
Distance from the transmitting antenna or array. Line-of-sight distance from the point of
measurement to the transmitting source is displayed both for operator feedback and for logging. This
feature is enabled when the latitude and longitude coordinates of the source are entered into PI 4100
memory by the operator.
Magnetic bearing from the measuring point to the
transmitting antenna or array.
The PI 4100 indicates Magnetic Bearing (True Bearing ± Declination) to the sourceif the latitude and
longitude and magnetic declination for the source has been entered into memory.
True azimuth (radial) from the source to the measuring point. Conventional use of Field Strength
data often requires the data to be presented as a plot, on polar graph (or map), referenced to True
North. The PI 4100 employs its internal GPS receiver to calculate and display the True azimuth, in
degrees, from the sourceto the measuring point both for operator reference and logging purposes.
Geographical coordinates of the measuring point. The PI 4100 internal GPS captures and displays the
Latitude and Longitude of the physical location from which a given measurement is conducted
(degrees, minutes, and seconds). This information can be stored with other pertinent data for future
retrieval.
Spectrum occupancy (visual display) for the RF spectrum immediately adjacent to the measured
frequency. The spectrum display screen provides 1.0 kHz resolution bandwidth and a sweep width
of either ±22 kHz or ±64 kHz from center. Amplitude resolution on-screen is 1.0 dB. Carrier
frequency is displayed (center screen) and an internal Marker can be moved in increments of 1.0 kHz
either side of the carrier to precisely measure frequency response or interference level (in dB below
carrier with 0.1 dB resolution) at the Marker frequency.
Functional elements: The PI 4100 Functional Block Diagram, Fig. 1, p. 10, shows the PI 4100's
functional elements.

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1.2 PI 4100 KEY FEATURES
● 126 dB dynamic range measuring receiver
● Digitally synthesized tuning in 1.0 kHz increments
● Spectrum display to facilitate various measurements (Field Strength and Spectrum occupancy) in a
single instrument
● Provisions for a third party calibration check, using their 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.)
● Magnetic compass to aid in the initial orientation of the integral loop antenna
● External RF input port (BNC) so that the instrument can be used as a stand-alone calibrated tuned RF
Voltmeter
● External RF output port (BNC) so that the buffered output from the loop antenna can be used to drive
external detectors and spectrum display devices
● USB port for downloading data from the PI 4100 internal memory to a compatible computer
● Comma separated data format for ease of importation to third party commercial software
● DC Field strength output for external recording
● DRM and HD Radiomeasurement capability with automatic correction

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1.3 SPECIFICATIONS
Field Strength Measurement
Frequency Range 520 kHz to 5.1 MHz or 200 kHz to 5.1 MHz, calibrated
Minimum frequency step 1.0 kHz
Measuring accuracy:
AM & Simulcast DRM ± 3 %
Pure DRM ± 6 %
Field strength measuring range:
AM & Simulcast DRM 28 dBuV/m to 154 dBuV/m (25 μV/m to 50 V/m)
Pure DRM, 4.5/5 kHz BW 33 dBuV/m to 146 dBuV/m
Pure DRM, 9.0/10 kHz BW 36 dBuV/m to 146 dBuV/m
Pure DRM, 19/20 kHz BW 39 dBuV/m to 146 dBuV/m
Measurement units μV/m-mV/m-V/m; mV/m only;
dBuV/m (dB above 1 µV/m)
Measurement bandwidth 1.0 kHz @-3 dB
Image rejection ratio 60 dB
Spurious rejection 75 dB
Harmonic measurement
Harmonics, menu-selected 2nd, 3rd, 4th, 5th
Measurement range to -80 dBc or lower, for carrier FS of (0.3 – 3) V/m
Spectrum Display
Modes Norm (referenced to center freq FS)
Peak (Norm with peak hold)
Abs (displays 20 - 140 dBuV/m FS)
Center frequency range Same as FS frequency range
Span (Sweep width) 128 kHz, 45 kHz
Resolution bandwidth 1 kHz
I/O Ports:
Data output jack USB B jack
Cal In jack BNC, nominal calibration input 700 mV rms
RF In jack BNC, RF input and dc FS output
RF Out jack BNC, RF output and dc cal detector output
Headphone jack Audio jack, 3.5 mm
Battery charging jack Power jack, 2.1 mm

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RF Voltmeter (RF In jack)
Input impedance 2500 Ω
Voltage range 30 μV to 40 V rms
Measurement units μV-mV-V; mV only; dBuV
RF Out 28 ±2 mV rms in 50Ω for 1 V/m FS, 200 kHz – 5.1 MHz
DC Field Strength output Proportional to dBuV/m, 1.0 Vdc @ 100 dBuV/m with a
1 MΩ load (10 mV/dB)
Audio outputs For AM and Simulcast DRM only:
Front panel speaker
Headphone jack, 3.5 mm, mono or stereo
(use disconnects speaker), up to 4.0 V p-p max output
Data items stored 28 items, listed in Users Guide Sec. 4.5.6
Battery power supply
Battery type Rechargeable NiMH, 7.2 V, PI supplied
Battery operating time 5 hours min., new battery
Battery recharge time 3 hours typical for full charge
Charging supply 11 - 15 Vdc, 1.2 Amperes min., 2.1 mm plug
Alternative battery Six AA cells in a PI-supplied battery holder
Environmental characteristics:
Operating temperature range 0ºC to 50ºC dry, RH 95% (non-condensing)
Operating altitude Up to 13000 ft. (4700 m)
Dimensions and weight:
Length, Width, Height L: 15 in, 38 cm W: 7 in, 18 cm H: 11 in, 28 cm
Weight 5.5 lb, 2.5 kg