DME SRB-406 - User Manual

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Overview

Function Description
Usage Features
Maintenance Features
Important Technical Specifications

The SRB-406 Emergency Locator Transmitter (ELT) is a survival-type transmitter designed for use on aviation life rafts. It broadcasts on 121.5 MHz, 243.0 MHz, and 406.028 MHz. The SRB-406 is designed for semi-permanent installation in survival rafts or raft devices and features automatic activation when it comes into contact with water. It also incorporates a manual activation means for operation on land.

Two models are available:

-001 Single Antenna Model: Configured for use on non-reversible, self-righting rafts.
-002 Double Antenna Model: Designed for rafts that are reversible.

Function Description:

The transmitter produces a signal for search and rescue when locating survivors of an aircraft accident. It can be automatically activated when the raft is deployed in water or manually activated. In the event that the raft is deployed on land, the ELT can be activated manually by touching both of the contacts on the antenna base with moistened fingers. ELT activation is indicated by a flashing light-emitting diode (LED) located on the top of the transmitter case.

The SRB-406 transmitter is protected inside a tough sealed plastic case. The case is designed to protect the transmitter electronics and battery from external loads encountered in packing the inflatable device.

Usage Features:

Arming Pin: The arming pin requires a pull force of approximately 8 pounds (from an angle of 0 to 60 degrees from the pin axis) to remove. The manufacturer of the inflatable device performs attachment of the lanyard to the raft. To activate the transmitter, pull the lanyard until the cylindrical arming pin is removed from its clip in the transmitter housing. Once removed, the unit is ready to transmit.
- For the -001 single antenna model, transmission begins when the antenna sensors are submerged (or moistened fingers are placed across both sensors of the antenna) or the water activation sensor detects water.
- For the -002 double antenna model, transmission begins when the antenna sensors are submerged (or moistened fingers are placed across both sensors of one of the antennas).
- Inserting the arming pin back into the clip will either disallow operation or cause an operational unit to cease transmitting. Transmission stops when the LED on the transmitter housing ceases flashing.
Antenna: The antenna(s) is an omni-directional, vertically polarized, whip antenna. The assembly consists of a pliant rubber base and a replaceable flexible whip antenna mounted in a base. The antenna is resonant at 121.5 MHz, 243.0 MHz, and 406.028 MHz. The rubber antenna base features activation sensors that operate by water contact or other low resistance contact. The base also incorporates an RF ground plane, which enhances RF transmission when in contact with the raft surface.
Water Activation Sensor:
- On the -001 model, a second wire lead from the transmitter case terminates in a low resistance water activation sensor. This lead is generally mounted so that, following normal inflation of the raft, the sensor will be located well below the water line. This sensor lead is detachable from the transmitter.
- On the -002 model, the water activation sensors are on both antennas.
Distress Message: The Model SRB-406 ELT transmits a radio signal on 406.028 MHz to satellites of the Cospas Sarsat network. This signal contains a short format digital message unique to each beacon, including manufacturer information, serial number, beacon type, and user/country code information. It is the buyer's responsibility to provide user and country code information and to register the beacon with the appropriate agency of the country under which the user will operate the aircraft. The beacon is programmed by DME Corporation during manufacture and can be reprogrammed if user/country code information changes.
Buoyancy: The SRB-406 is used only as part of a TSO-C69 or TSO-C69A raft, or a TSO C12c life raft. The transmitter/battery assembly is secured in a pouch that is an integral part of the raft; therefore, buoyancy of the SRB-406 is not required.
Instruction Tag: An instruction tag is attached to the antenna base, providing essential operating instructions to life raft occupants.

Maintenance Features:

Battery: Power is provided by a single lithium battery pack located within the transmitter housing. The battery pack uses 4 lithium/manganese dioxide, 1-1/4 "C" size cells arranged in series. Each cell is protected from short circuit by a manufacturer-installed safety device (PTC).
- Battery Pack General Precautions:
  - Temperatures near the melting point of lithium metal (180°C) will result in a lithium fire and rupture of the cells.
  - The battery pack must be protected from compressive loads.
  - The battery pack must be protected from condensation and exposure to water or other fluids.
  - Refurbishment and reconditioning of the battery pack is forbidden.
  - The battery pack must not be short-circuited. Short-circuiting for more than one minute is detrimental and may cause overheating.
  - Do not charge this battery pack; it is not rechargeable.
  - Store the battery pack in its original packaging until ready for installation.
- Battery Replacement:
  1. Remove the 6 Phillips screws from the bottom side of the unit.
  2. Lift out the battery.
  3. Depress the latch on the battery connector cable and slide the connector apart; properly dispose of the old battery.
  4. Slide the new battery connector into the corresponding connector half from the SRB-406 until it snaps into place.
  5. Place the new battery into the cavity, pushing cabling sufficiently to facilitate cover installation; ensure the battery does not pinch any wires.
  6. Place the cover over the unit, align attachment holes, and install the 6 screws. Torque screws to achieve a compressed gasket height of approximately .020 inches (free gasket height is .060 inches and approximate torque is 3 ± 0.5 inch pounds).
Press to Test Switch: A tactile-type switch, labeled PRESS TO TEST, is provided on the transmitter housing for testing proper operation.
- Momentarily depressing the switch will cause the LED to flash once immediately.
- After approximately 10 seconds, the LED will produce either 2 or 3 flashes, followed by approximately 15 seconds of off time, and then flash again. This sequence continues for 30 to 45 seconds and then ceases.
- NOTE: Two flashes indicate proper operation. Three flashes indicate a problem, requiring the unit to be returned to a repair station.
Tags and Labels: The transmitter case and battery case each have visible identifying labels providing the part number, model number, FCC identification number, FAA TSO number, and additional data.

Important Technical Specifications:

Transmitter Duty Cycle: 5 watt digital signal every 50 seconds, for 440 millisecond duration.
Homing Signal Tone Frequency: 700 Hz Sweep between 1600 and 300 Hz.
Homing Signal Tone Sweeping Rate: 2 to 4 times per second.
Operating Temperature Range: -20°C to 55°C (-4°F to 131°F).
Homing Signal Operating Range: 100-280 miles (160-450 km), subject to atmospheric conditions, receiver altitude, and sensitivity.
Battery Operating Life (Homing): 50 hours.
Battery Operating Life (406 MHz): 24 hours.
Battery Service Life: 5.0 years (service).
Volume Envelope: 22 cubic inches (360 cubic cm).
Weight:
- Single Antenna: 24 oz. (680 grams).
- Double Antenna: 27 oz. (765 grams).
Antenna: Flexible, Omnidirectional, Vertically Polarized, Field Replaceable, Whip.
Frequency: 121.5 MHz, 243.0 MHz, 406.028 MHz.
Maximum Storage Temperature Range (Battery Pack): -20°C to +40°C.
Maximum Installation Temperature Range (Battery Pack): -55°C to +85°C. At temperatures above 91°C, the battery pack is subject to venting.

DME SRB-406 Specifications

General

Brand	DME
Model	SRB-406
Category	Transmitter
Language	English