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Chelton Df 935 2 Pdf Install -

The Chelton DF 935 series is a high-performance tactical direction-finding system designed primarily for Search and Rescue (SAR) and Combat SAR (CSAR) operations. It is widely used on helicopters and fixed-wing aircraft to accurately locate personnel and emergency beacons. Core Capabilities

Wide Frequency Coverage: Features an integral synthesized receiver covering 30 MHz to 470 MHz.

Simultaneous Monitoring: Includes five dedicated Guard Receivers, allowing the system to monitor distress frequencies while taking bearings on all six receivers at once.

Advanced Decoding: Fully supports COSPAS-SARSAT message decoding and marine DSC (Digital Selective Calling) messages.

High Accuracy: Offers directional accuracy better than 5° rms, though this is highly dependent on proper installation and airframe interference. Installation & Integration Review chelton df 935 2 pdf install

Installing a 935 series system is a specialized modification, often requiring a two-stage approach: structural provisions and the actual equipment installation. Standard Installation Location DF Antenna

Typically installed on the belly of the aircraft for unobstructed signal reception. Control Panel Installed in the center console or cockpit dashboard. Mounting

Must be rigid and aligned exactly with the airframe (normal or inverted). Technical Specifications for Installers:

Electrical: Operates on 16.0 to 31.5 V d.c. with a 1.6 A maximum draw. The Chelton DF 935 series is a high-performance

Physical: The antenna unit has dimensions of roughly 286 x 286 x 90 mm and weighs approximately 3.8 kg.

Interface Options: Compatible with various data buses including RS 422, ARINC 429, and MIL-STD-1553B, allowing it to integrate with modern flight management systems.

Environmental Resilience: Compliant with RTCA DO-160C for vibration and temperature, and rated for altitudes up to 25,000 feet. Manufacturer & Industry Perspective

“The design of Chelton's 935 DF Antenna has been proven in a customer trial to have had 3x the range detection when compared to other competitor systems.” Chelton RF Cabling: Use low-loss coaxial cable (RG-142 or

“It can interface with Personnel Survival Radios (PSR) like AN/PRC-112 and PRC-434, providing range and bearing information.” AeroExpo Summary Review

The DF 935 is a "Gold Standard" for tactical rescue. Its primary strength lies in its parallel processing, which ensures that the crew never misses a distress alert on a guard frequency even while actively tracking a different signal. However, because it is an airborne system, its performance is heavily tied to the quality of the installation and the electronic noise environment of the specific aircraft.

For civilian use where military-specific features (CSAR) are not required, Chelton offers the ITAR-free 938-series. 935 Series Tactical DF Antenna | Chelton

Because the Chelton DF935 is an older legacy unit (often found in retrofit situations), the "installation" process is typically divided into two phases: Physical Installation and Configuration/Calibration.

Here is a feature overview and an installation guide based on standard aviation practices for this type of equipment.

3. Electrical Wiring & "2 PDF" Configuration

Phase 3 – Electrical (1 day)

  1. Crimp the D-sub pins (use size 20 contacts, Mil-spec). Double-check pin 22 (sync) and pins 18/19 (video out).
  2. Connect power via a 5A circuit breaker (28V DC). The PDF warns against sharing power with pulsed loads like transponders.
  3. Perform continuity and isolation tests: >100 MΩ between any pin and chassis.

3. Contact Avionics Distributors

Companies like Aircraft Spruce, L3Harris’ technical support, or Duncan Aviation often hold copies of legacy installation PDFs. Call their technical support line directly and ask for the "Chelton DF-935-2 installation data package." They are legally permitted to share it with certified installers.

Example Pinout from typical PDF (Note: Always verify with your specific revision):