Packaged Direction Finding Systems

Packaged Direction Finder Overview

Doppler Systems offers packaged systems allowing for easy installation and use our radio direction finding systems.  The packaged systems include a direction finding processor, an FM receiver, power distribution, a data interface to configure the system and obtain data from the system, and an appropriate antenna or antennas.  Additionally, some customers require wireless networking to connect fixed and/or mobile sites together to share data.  We also can provide laptop computers with our systems fully configured to interface with the direction finder and run our software.

A packaged system consists of the following items

The table below is a sample of the available configurations. We offer other configurations with different cable lengths, computers, and data radios.  Please contact us with your needs.

TypeFrequencyReceiverCable LengthLaptopData Radio
Mobile100 – 1000 MHzAOR SR220014 ftnonenone
Mobile100 – 500 MHzAOR SR220014 ftnonenone
Mobile500 – 1000 MHzAOR SR220014 ftnonenone
Mobile100 – 1000 MHzAOR SR220014 ftDell ATGVHF/UHF
Mobile100 – 1000 MHzAOR SR220014 ftDell XFRVHF/UHF
Mobile100 – 500 MHzAOR SR220014 ftDell LatitudeVHF/UHF
Mobile100 – 500 MHzAOR SR220014 ftDell ATGVHF/UHF
Fixed115 – 1000 MHzAOR SR2200100 ftnonenone
Fixed115 – 500 MHzAOR SR2200100 ftnonenone
Fixed250 – 500 MHzAOR SR2200100 ftnonenone
Fixed500 – 1000 MHzAOR SR2200100 ftnonenone
Fixed115 – 1000 MHzAOR SR2200100 ftDell ATGVHF/UHF
Fixed115 – 500 MHzAOR SR220050 ftDell LatitudeVHF/UHF

Processor Suite

The Processor Suite includes all the components necessary for a direction finding system mounted in a chassis and prewired. The antenna connections and external interfaces to the laptop are provided through a simple panel on the front of the chassis. The chassis in turn is mounted in a rugged modified laptop Pelican case, but it may easily be removed by pulling two spring action pull pins on the sides of the case. A cover with a bale mounts over the chassis to protect the equipment inside.  The bale provides a way to prop the Pelican case lid open allowing operation of the direction finder without removing it from the case.  The same processor suite is used for both mobile and fixed site systems.

The figure below shows a typical arrangement of the equipment in the case.  Each component is mounted to the chassis using hook and loop (Velcro) connections.  The front panel provides:

  • Connections for the direction finding antenna
  • DC power connections
  • Radio modem channel switch (optional)
  • Ethernet connection
  • Audio output
  • Auxiliary audio input
  • Laptop power (20 Vdc)
  • Data radio antenna connection
  • Power and data connections for a GPS and compass
Suite Components

The configuration shown is one of several possible equipment complements.  The processor suite is available without the data radio.  A configuration is also available with two direction finding processors and two receivers allowing the user to direction find on two frequencies simultaneously using a single fixed site antenna.

Fixed Site Kit

The Processor Suite and Fixed Site Kit comprise everything required to set up a single, dual, or three-band radio direction finding system.  The fixed site kit has two transit cases; one for the antenna and one for cables and accessories. 

The antenna case has room for a three antenna system with all the masts, frames, and biconical elements.  It has custom foam cutouts layered in the case to accommodate all the various parts of the fixed site antenna.  The case allows for easy packaging and transport of the fixed site antenna.

The case for the cables and accessories carries the GPS, the direction finder control cables, the mast clamps, and the coaxial cables for the direction finder and radio modem if installed. The kit is available for single, dual, and triple band antennas.

Mobile Kit

The mobile kit includes antennas for the bands to be covered, the mobile summer, the GPS receiver, the compass (optional), and all the cables necessary to setup and operate a mobile direction finder.  All of the equipment is packaged in a foam lined Pelican case.  Power cables are provided with cigar lighter plugs.  All antenna elements and cables are carried in a custom Mighty Pouch accessory bag.   If the processor suite contains a data radio the data radio antenna is also housed in the Pelican case.  The figures below show  typical a equipment complement. The mobile kit is available in a single, dual, or three-band antenna kit covering 100 MHz – 1000 MHz.

Radio Modem Antenna Kit

Radio modems in the processor suites of mobile and fixed site systems allow data exchange and text messaging between the sites.  Radio modems are typically used in remote areas where other forms of wireless communication are not available. VHF and UHF models are available and can be used in our systems. The fixed site radio modem requires an external antenna. Typically one site on a network acts as a control site so an omni-directional antenna is used at the control site.  This allows mobiles and remote sites to be located  within a circular pattern around the control site.  For remote fixed sites a direction yagi antenna is employed to increase the gain of the antenna and allow greater range for the remote site.  The radio modem kit comes with one omni-directional antenna, one yagi antenna, and coaxial cables to connect the antenna to the processor suite.  Photos of the equipment are shown below.