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LA Series

Aircraft DF

         + New aircraft DF units are no longer available but used units may be.   Call the factory.  This material is included as a reference  for existing equipment.  Factory repair service and some accessories are still available         +

The L-TronicsRegister.jpg (2200 bytes) LA Series Aircraft DF is a complete, independent, crystal-controlled receiver and indicator for permanent aircraft mounting. It does not require modification of an existing radio or loss of communications capability. Continuous monitoring of 121.5 is possible with the built-in silent alarm system. External antennas are required for the proper operation of this system. Antenna installations are illustrated on the aircraft antennas page with detailed information in the Installation Information section from the manuals.

Sensitivity, selectivity, and overload resistance of this receiver exceeds that of almost every light aircraft communications receiver, giving longer range and "clean" DF tracking. The built-in meters give both left-right homing and wide range signal strength indications simultaneously. Crystals are of a plug-in type and easily accessible for additional capability. Units are equipped with 121.5, 121.6, 121.775, and 243.0 MHz.The ELT Alarm is a special squelch that responds to the swept ELT/EPIRB signal but not to noise or voice. A 10-second delay before the alarm sounds prevents activation on tests. Reset is automatic when the signal goes off.

Auxiliary Receiver DF capability allows DF on any channel of the regular AM communications receiver to which it is attached. In many cases, no modification to the comm radio is required. The DF may be installed without the use of this capability initially then retrofitted at a later date, as all connectors and instructions are supplied at the time of purchase.

The 1-3/16" height and 2-pound system weight will make it easy to fit into most radio stacks. Over or under dash mounting is also possible and provision for driving a remote meter is standard. The receiver is front mounted for easy access. Audio is usually connected through an auxiliary amplifier input for cabin speakers.  Receiver outline and connector pinout are shown below.  The full manual PDF file (20mb) is available for download.   Copies of forms for an approved installation in a Cessna 172 are in this manual .  Installation instructions for the  remote meter  are  available here but new meters are not available..

 

 

SPECIFICATIONS: Receiver type: double conversion super-heterodyne with 2 separate RF tuners and common antennas; frequencies: 3 VHF, 2 UHF; tuner bandwidth (no realignment) 500 kHz full sensitivity, 4 MHz reduced sensitivity; DF sensitivity, VHF 0.15 u V or better (0.05 u V typical), UHF 0.3 u V or better; IF bandwidth 15 kHz; image rejection, VHF -55 dB min., -65 dB typical, UHF -40 dB typical; IF and spurious rejection, 75 dB min; audio output, 0.4W min. into 8 ohms; DF indication dynamic range -130 to -10 dBm typ.; signal strength indicating range -125 to -25 dBm typical; power 10-32 VDC, 300 mA max. Antenna: electrically switched twin monopole; antenna gain 2.5 dBd min. Weight including antennas 31 ounces. Operating temperature range -20 to +140deg. F. Case size 6-5/32" x 1-3/16" x 5-3/4" deep plus 2" for connectors.

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   1. +12/24V input power            6. Audio output

   2. Ground                                7. Remote meter +

   3. Meter light dimming bus       8. Remote meter -

   4. Key lead (aux DF only)          9. Remote alarm light

   5. Audio in (aux DF only)

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