The ATD-300 Traffic-Watch®
The ATD-300 Traffic-Watch is a passive receiver capable of detecting transponder replies from nearby aircraft and displaying their range and altitude on a bright 8-character dot matrix yellow LED display. It also provides distinctive voice warnings in relation to traffic proximity. The ATD-300 has a detection range of 5 nautical miles. The system consists of a receiver/indicator unit, antenna, power cord and headphone cable. The receiver is housed in a small aluminum box (2.75” x 0.75” x 5.0”) for easy location in the cockpit.
The ATD-300 provides distinctive voice warnings for traffic at different ranges. When set in the FAR mode and traffic is within 3nm and ±1,000ft of vertical separation "Traffic" will be annunciated. As the traffic gets closer to about 1nm and within ±1000ft of vertical separation the message will change to "Traffic Nearby". When set in the NEAR mode only traffic within 1nm and ±500ft of vertical separation will be annunciated by "Traffic Nearby". When set to MUTE there is no warning messages for any traffic, however traffic range and pressure altitude will still be indicated. When there is no traffic activity the ATD-300 will automatically indicate the host transponder MSL pressure altitude. A screwdriver adjustable volume control is located on the bottom side of the unit. Audio output to a speaker (8 ohms) or headphones (300 ohms) is provided on the rear of the unit. Unlike traditional active TCAS systems the ATD-300 determine traffic's range by its signal magnitude. Although not as accurate, this method allows for a compact low cost unit with a higher reliability than traditional active TCAS transmitters. The ATD-300 uses the onboard transmitted transponder altitude encoder data and the traffic's encoder data for relative altitude indication. Because these FAA-TSOd encoders are checked every two years, it assures that the indicated differential altitude is as accurate as that received by ATC. Since the ATD-300 has no internal altitude sensor, there is no need for periodic calibration checks or static port connections, particularly in pressurized aircraft. Thus making the unit easily portable between pressurized and non-pressurized aircraft. In areas of high traffic activity the display will show multiple traffics in an alternating fashion. This is most common for traffic between 4 and 5nm. Display preference is given to the closest traffic by distance and altitude. As traffic gets closer, background traffic display is reduced or eliminated.
The ATD-300 also features a built-in voltage-warning indicator that lets you know if the aircraft supply voltage is out of range. This function works in the background at all the times and is activated after engine start. If an out of range condition exists, the ATD-300 annunciates it by voice and by text.
|Altitude Decoding Range:
||-1200 to 30,700 feet MSL
||8 Characters dot matrix yellow LED
||8 and 300 Ohms Outputs
||11 to 30 VDC
||0.18 amps @ 14 VDC, 0.09 amps @ 28 VDC
||-20 °C to °C
||-1000 feet to 25,000 feet MSL
||Black Extruded Aluminum
||2.75" W x 0.75" H x 5.00" D
Host Altitude: 8,600ft MSL
When there is no traffic indicated, the ATD-300 reverts to indicate the onboard transmitted transponder altitude. This is the actual data received by ATC. If there is no Mode C altitude data transmitted, the ATD-300 indicates the transponder Mode A code.
Traffic Range and Relative Altitude: 5nm at 700 ft above
When there is traffic within 5nm and ±1000ft, the ATD-300 will automatically switch to the traffic display mode. If the traffic has no Mode C altitude data, the ATD-300 indicates range only.
Traffic Range and MSL Altitude: 5nm at 9,300ft MSL
When the left switch is set to MUTE it is possible to see all surrounding traffic within 5nm up to 30,700ft MSL. The ATD-300 will also revert to this display mode when there is no host altitude available. If the traffic has no Mode C altitude data, the ATD-300 indicates range only.
Low or High Voltage Condition
Whenever there is a low or high voltage condition on the bus, the ATD-300 will alert visually and by voice of this condition. This function is activated after engine start and runs on all the time in the background. It has priority over other display modes.
Low or High Voltage Condition
When there is no host transponder or traffic data the ATD-300 reverts to indicate bus voltage. This is normally shown during power up and taxing.