RF Guard®User Guide
EMC Test Design, LLC REV. 1
RF Guard®
RF Guard®is simple compact field strength monitor
that allows me to detect and evaluate the presence of
strong RF sources around - to provide piece of mind
and ensure the RF safety.
I can have this unit with me all the time, paying no
attention to its operation. If I get into high RF field
strength area - unit will give me proper notification.
I can also explore my environment, locate and
evaluate all strong RF sources and mitigate their
potential harm.
How to use RF Guard®?
- Push the red button once. Unit will play ascending
sound and turn on the two digits LCD display that will
show software revision, coin battery voltage and
average power density in %.Your RF Guard® is in
Normal Mode and ready for use.
-RF Guard®consumes very little power, so, once it is
turned on, it may stay on for many months, unless you
really want to use the installed coin battery for years by
shutting it down when not in use.
-Display will show 0.0 % reading when there is no
measurable RF field and will increase the reading up to
the 99 % at the highest measurable field.
- In addition to the display reading the color LED will
turn on Green-Yellow-Red when the average RF field
value crosses 0.1%, 1% and 10% value. If the display
reading is higher than 10% the internal speaker will
beep, alerting about the high fields.
-If unit detects the relatively high RF fields you may
be interested to find its source. To do that - push the
red button again. Unit will switch into Explore Mode
with blinking display and LED. In this mode LED
detects the RF field spikes typical for the cellphone and
Wi-Fi operation. Speaker will produce the level
dependent sounds that will allow you quickly find the
origin of the strong RF radiation. Play with it and you
will easily learn how it works.
-In Explore mode unit consumes much higher
power, so after 2 min. it will automatically return
to Normal Mode. You can switch back to Normal
Mode at any time by pushing the red button.
-If you make a long 3 sec. push - unit will turn
off entirely. This is accompanied by the
descending sound indicating that the unit is OFF.
-If you see two blinking dots instead of
numbers, battery must be replaced. The
CR2032 coin cell battery can be purchased from
most stores.
How to carry and hold RF Guard®?
-RF Guard® has built in dual antenna that detects
RF fields from the unit back (and to the less
degree - from the front). So, when you hold the
unit with display towards you it will measure the
RF fields from the sources located in front of you.
-Placing the unit in your front shirt pocket may be
convenient place but bear in mind that human
body absorbs the RF radiation and the readings
will be lower.
-When holding the unit keep your fingers at the
lower part of the RF Guard® body (below the
display) to avoid shielding the antennas.
-Also keep the RF Guard® away from metal
conductive surfaces - they create the undesirable
resonances that may affect the readings.
What does the RF Guard®reading mean?
-The RF Guard® display always shows the
average of the RF radiation power and is
calibrated to show 100% reading corresponding
to 1 mW/cm2 at 2.45 GHz.But what does it
mean?
-RF safety standards that we use today were
created by the end of the last century to protect
people from detrimental effects of the strong RF
fields, mainly - radars and powerful RF
transmitters. The primary health effect of the
radiation that was taken into account was -
thermal heating. The magic number of
1 mW/cm2 approximately corresponds to the
human tissue heating of 1°C.
So, based on that definition, 100% reading at
2.45 GHz is unsafe and should be avoided.
-But are the lower levels safe? If you have the
reading of 10% that will correspond to the
heating of 0.1°C(heating scales with absorbed
power) and should be safe? Unfortunately,
modern RF signals are digitally modulated and
their peak RF power not only many times higher
