Medium Aperture DF Technical Specification (Wide Aperture below)
Frequency ranges
VHF Aeronautical band 117 - 136MHz
VHF Marine band 156 - 162MHz
UHF Aeronautical band 225 - 400MHz
Antenna
VHF Nine element dipole array
UHF Nine element dipole array
Antenna Physical
VHF 2.13m diam, 5.5m above ground
UHF 0.8m dam, 3.7m above ground
Receiver
Channel spacing:
Type:
25kHz or 12.5 kHz or 8.33 kHz
Fernau 2035 or other standard communications receivers can beaccommodated Single channel or multi - channel
Modulation CW, AM and FM
The DF requires AM demodulation from all types of received signal. As an option, an FM demodulator board may be added to extract speech for FM signals (Marine applications)
Vertical Response Better than 60 elevation degrees at the low
end of the frequency band
Signal Polarisation Vertical
Polarisation Error <1 VHF, <0.5 UHF for equal vertical and horizontal fields
Bearing accuracy Site improvement factor 2.5 to 4.0 relative to narrow aperture system
Instrumental error 0.1 degree
Bearing response
Initial:
Subsequent:
Within 400 ms
Within 120 ms for 1 integration cycle n x 120 ms for n integration cycles ( n settable from 1 - 16 )
Sensitivity A bearing with 2 degree rms fluctuation due to noise is obtainable with a signal field strength of 5uV / m
Environment (ext)
Temperature:
Relative Humidity:
Wind speed:
Icing:
-40 C to + 60 C
100 %
up to 200 km / hour
4cm ice or 4cm wet snow
Environment (int)
Temperature Relative: Humidity:
0 C to + 55 C
95 %
DF System Doppler principle
DF Channels Min 1 - Max System dependent
Independent Operators Min 1 - Max System dependent
Operation Modes Local and remote mode
System Interfaces RS232, RS485, modem
Interface protocol Asynchronous
Message formats ASCII, Hex
Baud Rates Selectable
Power supply AC 115 / 230 V + 10 % (approx. 200VA per operator channel)
DC Option - 22 to 30 V, battery back up
Displays
Antenna site LCD displaying all active DF channels to 0.1 degree
Operator site Digital / Vector Indicator
0.5 degree numerical resolution
5 degree vector resolution
Persistence 2 - 8 seconds
Presentation any 2 of QTE, QDM, QDR, QUJ
Last bearing recall (Store) Illumination control
Freeze channel (Option)
Local Transmitter Inhibit (option)
Frequency control
Antenna site LCD with keypad
Display site Two line display with Keypad
User programmable hot keys
Dual frequency active facility
Test Oscillator activation
System Testing Display site Automatic / Manual test transmission at selected frequency
Remote calibration on each DF channel
Test oscillator
Frequency range:		 Optional
117MHz - 400MHz Supplied with antenna
Status information
BITE Built In Test Equipment
Antenna Dipole Failure Identification
Resolver system Individual module status
Display equipment Individual module status
Inter site Communications status
History System fault log

 

Wide Aperture DF Technical Specification
Frequency ranges
VHF Aeronautical band 117 - 136MHz
VHF Marine band 156 - 162MHz
UHF Aeronautical band 225 - 400MHz
Antenna
VHF Eighteen element dipole array
UHF Eighteen element dipole array
or Eighteen element unipole counterpoise assembly
Antenna Physical
VHF 3.66m diam, 5.5m above ground
UHF Dipole 1.67m diam, 3.7m above ground
UHF Unipole 7.6m diam, 3.7m high counterpoise
Receiver
Channel spacing:
Type:
25kHz or 12.5 kHz or 8.33 kHz
Fernau 2035 or other standard communications receivers can beaccommodated Single channel or multi - channel
Modulation CW, AM and FM
The DF requires AM demodulation from all types of received signal. As an option, an FM demodulator board may be added to extract speech for FM signals (Marine applications)
Vertical Response Better than 60 elevation degrees at the low
end of the frequency band
Signal Polarisation Vertical
Polarisation Error <1 VHF, <0.5 UHF for equal vertical and horizontal fields
Bearing accuracy Site improvement factor 6.0 to 10.0 relative to narrow aperture system
Instrumental error 0.1 degree
Bearing response
Initial:
Subsequent:
Within 400 ms
Within 120 ms for 1 integration cycle n x 120 ms for n integration cycles ( n settable from 1 - 16 )
Sensitivity A bearing with 2 degree rms fluctuation due to noise is obtainable with a signal field strength of 5uV / m
Environment (ext)
Temperature:
Relative Humidity:
Wind speed:
Icing:
-40 C to + 60 C
100 %
up to 200 km / hour
4cm ice or 4cm wet snow
Environment (int)
Temperature Relative: Humidity:
0 C to + 55 C
95 %
DF System Doppler principle
DF Channels Min 1 - Max System dependent
Independent Operators Min 1 - Max System dependent
Operation Modes Local and remote mode
System Interfaces RS232, RS485, modem
Interface protocol Asynchronous
Message formats ASCII, Hex
Baud Rates Selectable
Power supply AC 115 / 230 V + 10 % (approx. 200VA per operator channel)
DC Option - 22 to 30 V, battery back up
Displays
Antenna site LCD displaying all active DF channels to 0.1 degree
Operator site Digital / Vector Indicator
0.5 degree numerical resolution
5 degree vector resolution
Persistence 2 - 8 seconds
Presentation any 2 of QTE, QDM, QDR, QUJ
Last bearing recall (Store) Illumination control
Freeze channel (Option)
Local Transmitter Inhibit (option)
Frequency control
Antenna site LCD with keypad
Display site Two line display with Keypad
User programmable hot keys
Dual frequency active facility
Test Oscillator activation
System Testing Display site Automatic / Manual test transmission at selected frequency
Remote calibration on each DF channel
Test oscillator
Frequency range:		 Optional
117MHz - 400MHz Supplied with antenna
Status information
BITE Built In Test Equipment
Antenna Dipole Failure Identification
Resolver system Individual module status
Display equipment Individual module status
Inter site Communications status
History System fault log

The Company reserves the right to change specifications without notice.

Fernau Avionics Limited, Airport Executive Park, President Way, Luton, Befordshire, LU2 9NY, United Kingdom
Tel: +44 1582 483111 Fax: +44 1582 484404 Email: information@fernau.com