DETAILED CPM-700 PROCEDURE
REI
CPM-700
24
DETAILED INSPECTION SWEEP
Please note that in some areas which are close to high power commercial
transmitters such TV, AM or FM radio you will be using the Low Gain
setting (areas with more than ten segments displayed in Low Gain). It is
normal to see large signal level variations located throughout your sweep
area.
Often, when the Probe is held near wires or a metal object, the bar graph
level will increase, as well as the activity heard through the headphones.
This may not be a “bug,” but rather the metal acting as an antenna
extension. Verify by listening for your Known Sound Source.
There are available in the consumer market small FM wireless
microphones. These broadcast on the commercial FM broadcast band. In
order to meet FCC (USA) regulations, they must be very low power, about
two microwatts. This extremely low power makes them difficult to resolve
using the CPM-700. Fortunately, it also makes them quite useless as bugs
due to their short range – less than fifty feet under most circumstances.
Again, a close physical search, using the CPM-700 as an inspection tool, is
necessary.
NOTE: For best results in an RF-rich environment, test each object in the
room by placing the RF Probe against it, and noting if the level is higher
than the normal surrounding levels. The “Sniffer” Probe, included in the
CPM-Deluxe kit, is also very effective at isolating undesirable transmissions
in RF-rich environments.
Video Transmitters
Surveillance video transmitters sound the same through the headphones as
a “friendly” local TV signal. In many cases you can compare the RF and
audio signal levels by moving to another room. If you notice that a change
in light level in the room also changes the tone of the video buzz, then
localize the area that gives the strongest reading on the bar graph and
search for a transmitter and/or camera.