Series 6100 Radio Direction Finding System

The products for the series 6100 direction finders on this page are no longer in production.  However, we do continue to support them with customer assistance and repairs. Contact the factory if you need help with any of these products.

The series 6100 direction finders provide self-contained systems for mobile triangulation. Using the Auto Track software program on a laptop, you can record lines of bearing on a digital map. In addition, it uses a GPS receiver to measure the tracking vehicle’s location and heading. These are displayed as an icon on the map. Lines of bearing (LOB) are also shown on the map originating from the icon. When the user determines that a valid bearing is displayed, the LOB is stored and the icon changes. By driving to another location and taking another LOB, it finds the intersection indicating the emitter location. This process continues as the tracking vehicle closes on the emitter. The number of LOBs displayed may be limited to show only the most recent; however, all selected LOB data is written to a file that may be recovered later for analysis of the data.

Features of the Series 6100 Direction Finders

  • Broadband – 88 to 1000 MHz
  • All functions controllable from laptop
  • Selectable commutation frequency for optimum match to signal
  • 5 deg bearing accuracy (1 sigma)
  • Includes Auto Track software
  • Controllable signal averaging reduces multipath effects
  • Multiplexes four auxiliary serial ports (3 RS232 and 1 CIV) with direction finder data to laptop
  • Distributes 12 VDC power to all components from single cigar plug outlet

The system is based on the DDF6002 display/processor unit which uses advanced digital processing to estimate the bearing angle. It provides the multiplexing required to interface the GPS, NBFM receiver, and optional flux gate compass with a laptop. It does this through a single serial RS232 port. The DDF6072 distributes 12 VDC power to all of the equipment. The figure below shows a complete series 6100 direction finder system.

Series 6100 Direction Finders
DDF6100 Diagram

DDF6002 Display/Processor

The DDF6002 display/processor drives the RF summer with the waveforms required to mix the four antenna inputs smoothly and to produce the simulated Doppler modulation at the selected sweep frequency. The DDF6002 processes audio from the receiver to best estimate the bearing angle. You can use the DDF6002 as a standalone homing type radio direction finder. In addition, you can use it with the Auto Track software as a triangulation system. When used with an appropriate receiver, the DDF6002 meets the following specifications:

  • Type: simulated Doppler.
  • Commutation frequency: front panel selectable 300, 600, 1200 or 2400 Hz
  • RF operating frequency: 88 to 1000 MHz
  • Accuracy : 5 degrees (1 sigma)
  • DF sensitivity: typically -126 dBm
  • Monitor speaker: built-in, with audio amplifier and notch filter to eliminate commutation tone, 0.5 W maximum output
  • Sampling rate: best estimate calculated twice per second
  • Averaging: over last 1, 2, 5, 10 or 20 bearings, front panel selectable
  • Display/output: LED compass rose, plus 3-digit LED’s
  • Main serial interface: RS232 DCE, 9600 baud, 8 bit (non-ASCII) interface to laptop
  • Auxiliary serial interfaces: (3) RS232 DTE, programmable interfaces to GPS, compass and/or receiver; (1) CIV programmable interface to receiver
  • RF attenuator: 24 dB enabled from front panel
  • Calibration: manual or automatic using Auto Track software
  • Audio input range: 0.01 to 0.6 VRMS
  • Power requirements: 11 to 14 VDC, 1 Amp
  • Operating temperature: 0 to 50 degrees C
  • Dimensions: (HxWxD) 108x171x235 mm (4.25×6.75×9.25 in)
  • Weight: 1.9 kg (4.1 lb.)
  • CE compliant
DDF6002 Display Processor for Series 6100 Direction Finders
DDF6002 Display/Processor

SignalTrack Software

This Windows based program is supplied with the DDF6002. Serial data from the DDF6002 is decoded into the bearing angle, GPS latitude, longitude, heading, and velocity. SignalTrack uses a compass heading when the velocity is less than 4 km/hr. Otherwise the GPS obtains the heading. The tracking vehicle is located on the map image and displayed as an icon. A line from the icon on the map displays the true bearing direction. When the user presses the Insert key, it saves the bearing direction.

The program also provides control of the direction finder front panel controls and the receiver’s frequency. If you know the the location of a beacon transmitter, you can set up a convenient auto-calibration. For more information on this program, refer to SignalTrack.

SignalTrack Software

DDF6074 GPS

The DDF6074 is a compatible GPS receiver and antenna. Garmin makes the receiver, and it provides the NMEA0183 messages GGA and VTG every second. The GPS cable connects to a DDF6002 RS232 input and to the DDF6072 for power.

DDF6074 GPS Receiver

DDF6075 Compass

DDF6075 Compass

The DDF6075 compass is a version of the KVH model C100. We recommend it for operation from a stationary tracking vehicle. (In contrast, the GPS does not provide heading information when the tracking vehicle velocity is less than a few km/hr.) The compass sends NMEA0183 message HDG every second. The DDF6075 includes compatible connectors for the serial data and power used in the series 6100 system. Take care when placing this compass on the car to avoid magnetic structures.

DDF6072 Power Distribution Unit

The DDF6072 is a compact box that supplies 12 VDC power to the DDF6100 direction finder, receiver, laptop computer, GPS receiver and optional electronic compass. It utilizes twist lock connectors. The unit connects to the vehicle 12 VDC using a single auto power plug.

DDF6072 Power Distribution Unit