Mobile Radio Direction Finder

Doppler Systems offers mobile direction finders for frequencies from 100 to 1000 MHz.  The mobile system uses the same DF processor fixed site systems.  The mobile antenna utilizes roof mounted summing units and four vertical antennas.  Band switching is achieved either by removing one set of antennas and installing another set or we also offer multiple summing unit options that facilitate band switching from within the vehicle.

Mobile systems are available as packaged units with everything required to install and operate a mobile direction finder.  The packaged system provides a very convenient easy to setup system that is housed in two pelican cases that can be carried by one person.  Or we also provide direction finder components that can be used to configure a custom user solution.

A minimal mobile system consists of

Simple Radio Direction Finder Configuration Using Customer Furnished FM Receiver

Adding a GPS lets the user geolocate targets by using multiple transmissions and multiple locations to save bearing readings on a map in the software.  An optional yaw rate sensor provides better line-of-bearing accuracy if the vehicle is executing frequent turns.

Addition of a GPS Geolocation of the Transmitter

Our TargetTrack software works with the mobile system to display on a map the location of the vehicle and the measured bearing.  Multiple measurements provide a target location.  An Android based interface is also offered to facilitate simple homing operations. 

Mobile direction finders can be networked with other mobiles or fixed site systems using a mobile broadband connection or radio modems.

DF MethodSynthetic-Doppler with patented “Smooth Summing”
Frequency Range100 – 1000 MHz
Accuracy< 2.5 deg rms  (100 – 1000 MHz)
Resolution0.1 deg
Sampling Rate2 samples per second
Sensitivity-123 dBm (FM receiver dependent)
AveragingAdjustable from 1 to 20 samples
RF pulse detection100 ms minimum
Commutation frequencyAdjustable (250, 500, 1000, 2000 Hz)
Voltage Range11 – 14 VDC
Power6.5  W @ 12 VDC (processor and antenna)
Temperature Range-40 °C to 75 °C
CE CompliantPer EN 61000-6-2, EN 61000-6-4 AND EN 301 489-1