DETAILED CPM-700 PROCEDURE
REI
CPM-700
20
RF PROBE ANALYSIS
The Standard RF Probe contains a low noise, broadband amplifier (50 kHz
to 3 GHz) which boosts the weak “near field” signals emitted from RF
transmitters. Signal strength is displayed by the CPM-700 bar graph in
either high or low sensitivity ranges and is used to indicate the location of
an RF device by “homing in” on the highest level.
CAUTION: The RF Probe can be damaged by a high-
level electrostatic discharge to the antenna. In an area
where static discharges are likely, such as in dry
conditions, or on carpeting, touch each object to be
tested with your hand, if possible, before making
antenna contact.
*WARNING: Do not contact live power circuits!
A note concerning modulation: The CPM-700 is primarily sensitive to
amplitude information. Some transmitters may employ an unusual type of
modulation, hop frequencies, store information and output it in a burst or
have a very narrow bandwidth. These devices may not provide a strong
audio signal and therefore the CPM-700 may not give a clear audible
output of the Known Sound Source, but may only show a reading on the
LCD bar graph.
Be sure to investigate all suspicious RF levels.
A note concerning frequency: The CPM-700 and the Standard RF Probe
comprise a broadband RF receiver covering frequencies from 50kHz to
3GHz. Generally, the RF Probe is used extended to its full length. You can,
however, shorten the antenna to make a more focused search for higher-
frequency (i.e., shorter-wavelength) signals. The Broadband Microwave
Probe covers frequencies from 2GHZ – 12GHz, and is directional.
A note concerning power: Surveillance RF transmitters can be divided into
four power groups: micro power, low power, medium power, and high
power. Transmitting distance is dependant not solely on power but also
antenna placement and design, structural environment, ambient noise, and
the receiver and its antenna. High power bugs generally, though, can
broadcast a quarter mile or more with 100 milliwatts. Medium power
devices use 1 to 100 milliwatts for a distance of 300 feet to a quarter mile.