Product Overview
OAR DF4003A Doppler Radio Direction Finder – AS-IS for Repair
The DF4003A by Ocean Applied Research is a Doppler-based radio direction finder designed to locate RF sources by measuring signal bearing. This listing is offered AS-IS for repair, refurbishment, or parts use.
Once relied on by law enforcement and technical surveillance teams, the DF4003A represents a chapter in RF monitoring history where analog precision and field portability were paramount. While missing antenna and cables, the chassis, controls, and display still tell the story of a tool built for serious signal work. Its next use — whether as a repair project, a teaching aid, or a collector’s piece — belongs to you.
Product Condition
AS-IS condition. Offered without antenna or cables. Intended for parts, refurbishment, or experimental use. No guarantee of full operation.
Product Overview
Ocean Applied Research (OAR) produced specialized RF monitoring equipment for professional users. The DF4003A leveraged Doppler direction-finding principles to provide bearing data for locating unknown transmitters. Its compact, aluminum chassis integrated display and controls in a portable format suitable for field deployment.
Key Features
- Brand: Ocean Applied Research (OAR)
- Model: DF4003A
- Doppler-based radio direction finding technology
- Front-panel display and user controls
- Compact aluminum chassis with RF connectors
- Designed for professional monitoring and surveillance tasks
Applications
- Signal source triangulation and location
- Technical surveillance countermeasures (TSCM)
- Radio monitoring instruction and demonstration
- Component salvage for RF repair projects
- Collector or reference unit for historical RF test gear
Frequently Asked Questions
Does this unit power on?
Unit has not been tested due to missing antenna and cables. Offered AS-IS with no operational guarantee.
What is Doppler direction finding?
It is a method that determines the direction of a radio signal source by detecting frequency shifts as an antenna array rotates or simulates rotation electronically.
Who typically used the DF4003A?
Historically, units like this were deployed by law enforcement, government agencies, and technical surveillance specialists.
Can it be restored to working condition?
Restoration would require technical skill, proper parts, and suitable antennas. It is offered for those interested in repair or experimentation.
Why buy an AS-IS unit?
Buyers may seek it for spare parts, refurbishment, educational demonstrations, or as a collectible example of vintage RF monitoring equipment.
This listing is for one OAR DF4003A Doppler Radio Direction Finder in AS-IS condition, offered without antenna or cables.
