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Acoustimeter User Manual
Safety Instructions
Please read through these instructions carefully
before operating the instrument. These contain
important information regarding usage, safety and
maintenance.
The instrument is not waterproof and should not be
used outdoors in the rain without extra protection.
If necessary, please cover the instrument with a
clear plastic bag that does not have holes in it.
Exposing the instrument to high temperatures or
dropping the meter on to a hard surface may cause
it to stop functioning properly.
The meter is sensitive and is intended to measure
typical modern environmental exposures.
Do not take it close to high power radiofrequency
transmitters or put it inside a microwave oven.
Clean the case using a damp cloth if necessary and
do not use chemicals.
This instrument is not intended to be serviced by the
user, nor does it need any special maintenance.
Unscrewing the case may void the guarantee.
While EMFields considers that the information and
opinions given here are accurate, you must rely
upon your own skill and judgement when making
use of the information contained in this manual.
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Contents
Safety Instructions......................................................2
Technical Specifications .............................................4
Introduction ...............................................................5
Layout of the meter ...................................................6
Operation and use......................................................7
Setting up for first use........................................... 7
Taking measurements ........................................... 7
Audio ..................................................................... 9
EMFs – What to measure? ...................................... 10
What are EMFs? .................................................. 10
Electromagnetic spectrum guide ........................ 11
Guidance levels ....................................................... 12
Various exposures and effects ................................ 14
Why are there two different readings?............... 17
Digital and Analogue signals................................ 20
Typical real-life exposures....................................... 22
Troubleshooting ...................................................... 26
Warranty ................................................................. 28
4
Technical Specifications
Typical frequency response using the internal
antenna:
200 MHz – 8000 MHz ± 6dB ± 0.02 V/m
Measurement Range:
The LCD displays peak-hold, peak and average
values. Updated about 2.5 times per second.
Note: Peak Hold is reset/cleared using front button
Peak readings: 0.02 - 6.00 V/m
LED Scale: 15 levels, from 0.02 to 6 V/m
Updated 5 times per second.
Average readings: 1-100,000 µW/m2
LED Scale: 15 levels, from 1 to 100,000 µW/m2
Updated 3 times per second.
Note: 100,000 µW/m2equals 10 µW/cm2
The audio can be heard at levels below 0.02 V/m.
Power
Current: 100 to 150 mA at 3 volts
(2xAA 1.5V Alkaline or NiMH 1.2V rechargeable cells)
Battery Life is typically 15 hours (alkaline) and up to
25 hours (NiMH 2000+ mAh cells). ‘Low battery’ is
indicated.
Working temperature range -20 °C to +40 °C
Dimensions: 190mm x 102mm x 33mm.
Weight: 280g, 330g with batteries.
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Introduction
The Acoustimeter will enable you to make quick and
informed judgements regarding radiofrequency (RF)
Electromagnetic Fields (EMFs) in your environment.
The Acoustimeter measures all RF EMF sources from
200 MHz to 8000 MHz (8 GHz) which, in practical
terms, covers most modern wireless communication
RF signals that you will be exposed to.
This includes mobile phone networks (2G, 3G, 4G,
5G*), local wireless networks such as WiFi (2.4 and 5
GHz), digital cordless phones (DECT), and many
other sources that will expose you to RF energy.
Readings are shown on both a 2-line OLED display
and two series of graduated LED lights. The LEDs
update rapidly, allowing you to quickly gauge the
levels in an area and find any hot-spots.
The Acoustimeter also feeds the detected incoming
signals to a loudspeaker which will help you to
determine what type of signal is being detected.
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Layout of the meter
Key:
1. OLED Display
2. Peak signal LEDs
3. Average power LEDs
4. Volume controls (5 levels, - lower, + higher)
5. Clear (peak) hold button
6. Power button
7. Internal Antenna location
8. Loudspeaker
9. Battery compartment (for 2x AA cells)
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Operation and use
Setting up for first use
Ensure that the 2 AA batteries are correctly installed.
Press the POWER button. The LEDs display a moving
pattern and the OLED displays a start-up screen:
“Acoustimeter
Initialising... ”
The audio is off at start-up. Change the volume in
pre-set stages by pressing the VOLUME + and
VOLUME - buttons.
Taking measurements
The instrument displays the peak signal strength
and the average power flux density (PFD) on both
the LEDs and LCD. We discuss what these mean in
the “Why are there two different readings?” part of
the next “EMFs – what to measure?” section.
It is important to remember that RF EMFs create
“hot-spots” due to reflections, so both the position
and orientation of the instrument is very important.
Moving the instrument small distances can result in
noticeable real differences in the detected levels.
To get the most accurate reading, slowly rotate the
instrument in each direction until you find the
highest reading, and then hold it still to take the
measurements.
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Ideally hold the meter as shown in the picture. Try
to keep the Acoustimeter at least 30cm away from
your body when taking readings. Keep your hands
towards the bottom of the instrument.
If you wish, the Acoustimeter can also be placed
(preferably upright) on a surface.
We recommend taking the highest reading found
in any one spot, as this is when the antenna is
optimally aligned with the incoming signals.
The “Peak-hold” function will display the highest
peak reading measured until the instrument is
turned off and on again, or until the CLEAR (PEAK)
button is pressed.
When you have finished taking measurements, press
the POWER button again to turn the AM11 off.
The AM11 will turn itself off after 8 minutes of
inactivity to preserve battery.
9
Audio
The audio feature allows amplitude changes in the
incoming signals to be heard as audio, which can
help in determining the type and source of RF.
Many common EMF sources produce a distinct set of
sounds via the Acoustimeter, and so with a little
practice, you can soon learn to identify a source type
via audio. Some sound samples to help you identify
different signals are available on:
http://www.emfields-solutions.com/rf
Most modern digital EMF sources are “pulsed”,
meaning they have an amplitude-modulated signal.
However, some sources are not amplitude
modulated, including analogue sources, and these
will not produce much sound even with the volume
turned up. We explain more about this in the “Digital
and Analogue signals” section.
It is sometimes possible to hear voices and music
when close to powerful broadcast AM radio
transmitters. These are outside of the normal RF
frequency detection range of the meter, but they are
sufficiently powerful transmitters to be picked up.
When no LEDs are illuminated any regular very quiet
sounds should generally be ignored as they are due
to the internal functioning of the meter. However,
incoming pulsing RF signals can still
often be heard when the LCD is displaying readings
of <0.02 V/m and < 1 µW/m2.
10
EMFs – What to measure?
What are EMFs?
EMF is usually taken to mean “time-varying electro-
magnetic field” and cover an enormous spectrum of
different phenomenon. These include, but are not
limited to, “power frequency” fields (given off by any
AC electrical device), mobile communication signals,
TV and radio signals, military radars, infra-red, visible
light, ultra-violet, x-rays and gamma rays. We
provide a brief over-view guide on the next page.
Their interaction with the human body varies and
there are few clear correlations between frequency,
duration, exposure level and health effects, though
there is a great deal of peer-reviewed published
evidence of real effects at both high and low
exposure levels. Further research into each part of
the spectrum and different modulation types is still
required. It is almost certain that sensitivity to EMF
exposure varies from person to person.
Some electric and magnetic fields are part of the
natural environment that life on Earth evolved with.
High electric fields cause lightning and magnetic
fields from the Earth’s core allow compasses to
work. However, we have not evolved with the
enormous increase over the last 100 years in
radiofrequency exposure (see graphic on page 14),
and there is steadily mounting evidence that they
may cause unexpected adverse effects on health.
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