EMFields AM-10 Manuale utente
Acoustimeter
User Manual
2
Safety Instructions
Please read through these instructions
carefully before operating the instrument.
This contains important information
regarding usage, safety and maintenance.
The instrument is not waterproof and
should not come into direct contact with
water, nor should it be used outdoors in the
rain. If it is raining and you want to take
measurements outside, please cover the
instrument in a plastic bag that does not
have holes in it. Clean the case using a
damp cloth if necessary and do not use
detergents.
This instrument is not intended to be
serviced by the user neither does it need
any special maintenance. Unscrewing the
case will void the guarantee.
This instrument is sensitive to heat and
impact. Exposing the instrument to high
temperatures or dropping the meter on to a
hard surface may cause it to stop
functioning properly. It may not display
properly while it is in temperatures below
freezing (0°C).
3
Contents
Safety Instructions .......... 2
Technical Specifications .. 4
Introduction .................... 5
Layout of the meter ........ 6
Operation and use .......... 7
LED displays ..................... 13
Troubleshooting .............. 14
Exposure Guidance ......... 16
Guarantee ...................... 18
Approvals and Contact ... 19
4
Technical Specifications
Typical overall frequency response using the
internal antenna:
200 MHz – 8000 MHz ± 3dB ± 0.01 V/m
150-200 MHz and 8-10 GHz ± 6dB
Measurement Range:
Peak: 0.02 - 6.00 volts per metre, V/m
Average 1-100 000 microwatts/sq.metre
µW/m2
The detector can respond to levels below
0.02 V/m - audio from demodulation may
be heard at levels below 0.02 V/m.
The LCD displays peak-hold (since turned
on), peak and average values.
Peak LED Scale Points updated c. 100 ms:
0.02, 0.03, 0.05, 0.07, 0.1, 0.2, 0.3, 0.5,
0.7, 1, 1.5, 2, 3, 4.5, 6 V/m
Average 6400 samples updated c. 250 ms:
1, 5, 10, 25, 50, 100, 250, 500, 1 000,
2 500, 5 000, 10 000, 25 000, 50 000,
100 000 µW/m2
Power:
c.90-125 mA at 3 volts (2xAA Alkaline or
NIMH rechargeable cells @ 1.2 - 1.5V)
Battery Life: typically 15 to 20 hours.
‘Low battery’ detection is indicated.
Size: 190mm x 102mm x 33mm (LxWxD)
Weight: 275g, excl. batteries, 320g with.
5
Introduction
The Acoustimeter has been designed to
enable you to make a quick and informed
judgement regarding the level and nature of
microwave signals in your environment. The
Acoustimeter is a broadband meter that
measures the totality of the radiation in the
range 200 MHz to over 8000 MHz (8 GHz),
which covers the frequencies used by most
modern communication systems in our
everyday environment. It was designed
using the experience gained from many
years of practical RF and microwave
measurements using a wide variety of
professional instruments.
Readings are shown on both an LCD display
and two series of graduated LED lights. The
LEDs update rapidly, and allow you to
quickly gauge the levels in an area and find
any hot-spots. The Acoustimeter also has a
loudspeaker (and audio output socket for
headphones or an audio recorder), allowing
you to determine, with a small amount of
practice, what type of device is creating the
signals.
Sound samples and a RF unit converter to
help you identify different signals are
available on:
http://www.emfields-solutions.com/rf
6
Layout of the meter
Key: 1. Display
2. Peak signal LEDs
3. Average power LEDs
4. Audio jack, mono, 3.5mm
5. Volume control
6. On - Off switch
7. Internal Antenna
8. Loudspeaker
9. Battery compartment
7
Operation and use
Ensure that you have correctly inserted
correct batteries (2 x AA cells). Move the
power switch into the “On” position. The
LEDs should at once display a moving
pattern across all LEDs and the LCD should
briefly display
“Acoustimeter v04 © EMFields 2015”
changing to readings after a short time.
Hold the bottom of the instrument in one
hand at least 30cm from your body as close
proximity to your body will affect the
readings. Keep your hands away from the
top of the instrument as the antenna is
located inside the case at the rear towards
the top. The Acoustimeter can be located
upright on a surface, but people nearby can
still affect the RF/microwave levels.
Adjust the volume to suit level (usually
somewhere about mid-volume is best; only
use maximum with weak signals).
The instrument will display the peak signal
strength and the average power on both
the LEDs and the LCD. Slowly turn the
instrument around in all directions for the
best reading. Hold it still to take a reading.
Bear in mind that even moving the meter
small distances can result in detecting very
different levels of microwave energy.
8
Microwaves are reflected off the ground
and other surfaces so it is important to
check all angles. The highest readings will
often be found when holding the
instrument facing you at an angle between
horizontal and vertical.
We recommend taking the highest reading
found in any one spot, as this is when the
antenna is most closely aligned with the
directionality of the signal. The “Peak-hold”
function will display the highest peak
reading measured until the instrument is
turned off and on again.
If there is hardly any noise with the volume
turned up then the instrument is not
detecting any amplitude modulated
(i.e. “pulsing”) signals. Various sounds
represent the amplitude modulation and
digital pulsing of RF signals detected by the
instrument.
It is sometimes possible to hear voices and
music when very close to powerful medium
and short-wave AM transmitters, which are
outside of the normal RF frequency
detection range of the meter.
When no LEDs are illuminated any regular
very quiet ticking sounds should be ignored
- they are due to the internal functioning of
the meter.
9
Why are there two different readings?
The Acoustimeter is unique in the way it
displays information about its readings.
There are two different displayed results,
showing values for Peak and Average
measurements. At first, this may seem
confusing. We believe that it is important to
know both when assessing your exposure to
modern telecommunication signals. We
believe that it is the peaks in pulsing signals
that are the most bio-active at typical
modern relatively low exposure levels.
Digital and Analogue?
Most modern wireless devices use a digital
system of communicating. These include
mobile phones, WiFi, Cordless phones
(DECT), Digital TV & DAB Radio. Many
modern digital systems turn the signal on
and off at high speeds to represent data,
often with extra gaps between data bursts.
This produces a non-continuous signal,
which we describe as “pulsing”. The
Acoustimeter allows you to hear this as one
way of identifying the signals.
An analogue signal is a system of
communication that is not digital. They use
a continuous carrier, and instead of turning
“on and off” to represent data, will vary the
frequency (FM) or strength (AM).
10
Differences between peak & average
With an analogue system, the peak and
average levels should be similar, as the
signal is continuously on while it is being
used. However, because most digital
systems spend a large proportion of their
time not transmitting, the average level
does not represent the actual waveform
even though it is technically accurate as
shown in the diagrams below.
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