solution could consist of a wide area augmentation system (WAAS) capable GPS and
a Mode-S transponder. At present, no equipment available has the required technical
standard order certification from the FAA,
so if you have existing equipment in your
aircraft it may need at least a software
upgrade. For example, Bill Stone of Garmin
told me that pilots who already own a GTX
330 Mode-S transponder can upgrade it for
ADS-B for $1,200, far less than the cost of
buying a new transponder.
Alternatively, you might purchase a 978
UAT transmitter or transceiver. For example, the Garmin GDL 90 UAT includes an
internal WAAS-capable receiver and a 978
MHz transceiver. By adding this unit, which
lists for $7,995, you’ll automatically have
ADS-B Out capability. Connect it to a compatible display, such as a Garmin GNS 430 or
530 GPS, and you’ll have ADS-B In capability. However, the current version of the GDL
90—like all other ADS-B equipment currently on the market—isn’t yet certified, so
you are probably better off waiting until certification is received.
a “custom payload,” meaning they only
broadcast traffic threats for participating
aircraft—those equipped with an ADS-B Out
transmitter. Thus if you have only an ADS-B
receiver, you will see traffic threats for
ADS-B Out equipped aircraft, but you won’t
see traffic threats for your own aircraft!
Also, if you buy a 978 UAT receiver, don’t
expect to see any weather data until after
you’re in the air, except at a few airports that
have an ADS-B ground station located
nearby. By contrast, satellite-based service,
such as XM weather, works equally well on
the ground as in the air.
ADS-B IN CAPABILITY
The final standard for ADS-B In has not
been released, so manufacturers aren’t able
to design for it with certainty. Thus any
ADS-B receiver solutions you might buy
today may have to be upgraded later, or possibly replaced.
An ADS-B In solution consists of an
ADS-B receiver and a display for viewing
traffic—and in the case of a 978 UAT—
weather data. For a 1090ES solution, a
Mode-S transponder won’t work as an
ADS-B receiver. However, if you have a traffic awareness system (TAS), you may be able
to upgrade that system. That’s because it
receives on 1030 MHz, the frequency used
for ADS-B In for 1090ES solutions. For
example, Garmin’s GTS 800 TAS system
already includes ADS-B In.
But be careful about purchasing just an
ADS-B receiver with the idea that you’ll be
viewing all traffic data. In the FAA’s original
deployment of ADS-B in Alaska, the ADS-B
ground stations broadcast in unlimited
mode, meaning that all traffic data was continuously broadcasted. However, new
ADS-B ground stations being deployed by
ITT in the lower 48 states broadcast
