Decatur Electronics G3 - EMI and Feedback Interference

G3
™
User’s & Installation Manual
7/October/2020
55
• Targetstravelingatspeedswhichareclosetothe
patrol speed can also mimic this condition and will be
rejected. The target window will show a blank speed as
the radar detects the harmonic. To process this type of
target, simply increase or decrease your patrol speed by
at least 3 km/h.
8.2.8 Radio Frequency Interference (RFI)
The system can inadvertently process radio energy as Doppler
speeds, including that from police radios, airport radar, microwave
transmission towers, CB radio transmitters, and AM/ FM
transmission towers. For this type of interference to occur, the
radar unit must be operating very close to the radio transmitter.
The G3™ contains an RFI detection circuit that detects excess radio
frequency energy. When stray radio frequency energy reaches
an excessive level, the system displays the RFI message and stops
processing and displaying speeds. The system resumes normal
operation when the RFI condition no longer exists. At that time,
any locked speeds will display again.
8.2.9 Shadowing
In Moving mode, the radar processes two speeds - patrol and
target. The stronger of the two, the patrol speed, is created when
the radar beam reects from passing stationary objects, such as the
pavement or terrain the motor vehicle is traveling on. However, in
rare cases, some situations cause return signals to be larger than
the reection from the ground such as when the patrol motor
vehicle is rapidly overtaking a slow-moving 18-wheeler. The radar
may use the large return signal generated by the semi’s trailer
ignoring the ground return.
This results in an articially low Patrol speed. The computer would
then subtract this articially low speed from the closing speed and
assign a higher speed to the target.