The Non Directional Beacon (NDB)
design is primarily for use as a locator
in aid of final approach. The NDB 436
radiates vertically polarized signals in
the frequency range of 190 to 550
kHz. The coverage volume is typically
omnidirectional in the azimuth plane.
The navigational signal contains no
coded information except an
amplitude modulated Morse code,
periodically repeated, which identifies
the transmitter. The airborne Direction
Finder indicates to the pilot the
direction of maximum signal strength,
which points directly towards the
ground station.
Due to the frequency band used, the
antenna is always electrically short
with consequently very low radiation
efficiency.
Therefore a suitable Antenna Tuning
Unit (ATU) is required to properly
match the transmitter to the antenna.
In addition, the ATU automatically
compensates for antenna variations that
take place due to weather conditions
etc. The ATU can operate into various
antenna types such as mast, monopole
whip or symmetrical T.
The NDB 436 is designed in full
compliance with ICAO Annex 10 with
a transmitter power output of 100 Watts.
It is conceived as a full dual system,
but can be supplied in reduced
redundancy configurations (i.e. with
single transmitter, single monitor, or
both). It easily interfaces with a MSK
modulator for DGPS applications. The
NDB 436 can be connected to a variety
of power sources such as solar power.