Extech 480836 Operating Manual

User's Guide

RF EMF Strength Meter

Model 480836

1.0 - Safety Information

CAUTION

• Before making a measurement, check if the low battery symbol ( + ) is
shown on the display when the meter is switched on. Replace the
battery if the symbol is displayed.

• In the case of prolonged storage, it is preferable to remove the battery from
the meter.

• Avoid shaking the meter, particularly in the measurement mode.

• The accuracy and function of the meter may be adversely affected by

exceeding the specified limits as well as by improper handling.

DANGER!

• Use caution when working in the vicinity of powerful radiation sources.

• Persons with electronic implants (e.g. cardiac pacemakers) should avoid

powerful radiation sources.

• Observe the local safety regulations.

• Observe the operating instructions for equipment that is used to generate or

conduct electromagnetic energy.

• Be aware that secondary radiators (e.g. reflective objects such as a metallic
fence) can cause a local amplification of the field.

• Be aware that the field strength in the near vicinity of radiators increases

proportionally to the inverse cube of the distance. This means that enormous
field strengths can result in the immediate vicinity of small radiation sources
(e.g. leak in waveguides, inductive ovens).

• Field strength measuring devices can underrate pulsed signals, particularly with
radar signals in which case significant measurement errors can arise.

• All field strength measuring devices have a limited specified frequency range.

Fields with spectral components outside of this frequency range are generally
incorrectly evaluated and tend to be underrated. Before using field strength
measuring devices, you should thus be certain that all field components to be
measured lie in the specified frequency range of the measuring device.

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2.0 - Introduction

2-1 Fundamentals

 Electromagnetic Radiation

This meter is used to indicate radiated electromagnetic fields. Wherever there is
a voltage or a current, electric (E) and magnetic (H) fields arise. Examples
include the electromagnetic fields from radio broadcasting and TV transmitters.

 Electric Field Strength

This is a field vector quantity that represents the force (F) on an infinitesimal unit
positive test charge (q) at a point divided by that charge. Electric field strength is
expressed in units of volts per meter (V/m).

Use the units of electric field strength for measurements in the following situations:

• In the near-field area of the source.

• Where the nature of the electromagnetic field is unknown.

 Magnetic field strength (H) :

This is a field vector that is equal to the magnetic flux density divided by the
permeability of the medium. Magnetic field strength is expressed in units of
amperes per meter (A/m).

 Power density (S) :

Power per unit area in the direction of propagation, usually expressed in units of
watts per square meter (W/m2) or, for convenience, units such as milliwatts per
square centimeter (mW/cm2).

 The characteristic of electromagnetic fields :

Electromagnetic fields propagate as waves and travel at the speed of light (c).
The wavelength is proportional to the frequency.

λ(wavelength) =

Near-field is assumed if the distance to the field source is less than three
wavelengths. For far-fields, the distance is more than three wavelengths. In the
near-field, the ratio of electric field strength (E) and magnetic field strength (H) is
not constant, so measure each separately. In the far-field, however, it is enough
to just measure one field quantity, and compute the other accordingly.

2-2 Application

 High frequency (RF) electromagnetic wave field strength measurement.

 Mobile phone base station antenna radiation power density measurement.

 Wireless communication applications (CW, TDMA, GSM, DECT).

 RF power measurement for transmitters.

 Wireless LAN (Wi-Fi) detection, installation.

 Spy camera, wireless bug finder.

 Cellular/Cordless phone radiation safety level.

 Microwave oven leakage detection.

 Personal, environmental EMF safety.

c (speed of light)

f (frequency)

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2-3 Features

This meter is a broadband device for monitoring high-frequency radiation in the range of
50MHz to 3.5GHz. The non-directional electric field and high sensitivity also allow
measurements of electric field strength in TEM cells and absorber rooms.

The unit of measurement and the measurement types are expressed in units of electrical
and magnetic field strength and power density.

At high frequencies, the power density is of particular significance. It provides a measure
of the power absorbed by a person exposed to the field. This power level must be kept
as low as possible at high frequencies. The meter can be set to display the
instantaneous value, the maximum value measured or the average value. Instantaneous
and maximum value measurements are useful for orientation, e.g. when first entering an
exposed area.

 50MHz to 3.5GHz Frequency range.

 For isotropic measurements of electromagnetic fields.

 Non-directional (isotropic) measurement with three-channel measurement sensor.

 High dynamic range due to three-channel digital processing.

 Configurable alarm threshold and memory function.

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3.0 - Specifications

3-1 General Specifications

• Measurement method: Digital, triaxial measurement.

• Directional characteristic: Isotropic, triaxial.

• Measurement range selection: One continuous range.

• Display resolution: 0.1mV/m, 0.1μA/m, 0.001μW/m

• Setting time: Typically 1s (0 to 90% of measurement value).

• Display refresh rate: Typically 0.5 seconds

• Display type: Liquid-crystal display (LCD), 4 digit.

• Audible alarm: Buzzer.

• Units: mV/m, V/m, μA/m, mA/m, μW/m

2

, mW/m2, μW/cm2

• Display value: Instantaneous measured value, maximum value, or maximum
average value.

• Alarm function: Adjustable threshold with ON/OFF.

• Manual data memory and read storage: 99 data sets.

• Dry batteries: 9V NEDA 1604/1604A

• Battery life: > 15 hours

• Auto power off: 15 minutes.

• Operating temperature range: 0°C to +50°C

• Operating humidity range: 25% to 75%RH

• Storage temperature range: -10°C to +60°C

• Storage humidity range: 0% to 80%RH

• Dimensions: Approx. 60(W)×60(T)×237(L)mm.

• Weight (including battery): Approx. 200g

• Accessories: Instruction manual, battery, carrying case.

2

, 0.001μW/cm2

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