On Feb 9, 4:10*am, "
wrote:
On Feb 8, 11:30*pm, Eric Greenwell wrote:



Mike Schumann wrote:
But sometimes it's all not enough...
Unfortunately true. *Us pilots need all the help we can get.

Vaughn
Even if you do everything right, you can still be surprised. *A power
pilot could easily be monitoring the local CTAF frequencies on a cross
country only to unexpectedly encounter a glider who is talking on
123.3 (what power pilot would think of monitoring that???).

The only real solution is universal deployment of ADS-B on every
aircraft, including gliders, balloons, UAVs, military aircraft, etc.
With that, if you attach your ADS-B transceiver to a GPS, you will see
everybody. *No surprises. *The technology exists for ADS-B
transceivers to be available for ~$1K. *The only thing missing is the
political will in the FAA to permit this class of avionics to be
certified for VFR use. *We need to make our voices heard that we need
this NOW.

I can't find good graphics showing current ADS-B coverage, or scheduled
coverage. Can someone point out a source? A talk at the convention said
the FAA is holding well to it's installation schedule, which was good to
hear.

The July 2009 graphic I found didn't show much coverage out West, and
surprisingly, none in Colorado, so I don't trust it much.

--
Eric Greenwell - Washington State, USA
* Change "netto" to "net" to email me directly

* "A Guide to Self-launching Sailplane Operation" atwww.motorglider.org-Hide quoted text -

- Show quoted text -

What so you mean by "coverage"
I thought the beauty of ADS-B is that it is an "aircraft to aircraft"
based system, no ground "coverage" necessary.
The other beauty is that ADS-B is NOT radar based, it is GPS based, so
it works in remote areas, like ALASKA where it is considered very
successful in reducing mid air collisions.

Another feature is ADS-B is the "extended squitter" which basically
broadcasts your GPS loacation every second, whether you transponder
gets "interrogated" or not.

We recently installed a Garmin GDL 90 for a customer.........

The unit itself is huge, like two shoe boxes in size, and
heavy........costs around $8K......This is a "blind box".. *It
requires additional hardware to display info, it also requires THREE
antennas..........then there is the installation cost,...it is not so
simple to install.......etc.

Cookie

You need an ADS-B ground station for TIS-B (not to be confused with
Mode S TIS - completely different): so an ADS-B (either UAT or 1090ES)
receiver equipped aircraft can receive position reports based on
current SSR/transponder location of aircraft that are not equipped
with an ADS-B transmitter. Once you/the threat aircraft is outside SSR
coverage you will not "see" the threat via TIS-B. If a threat aircraft
is not equipped with a transponder you will not see it via TIS-B. You
need TIS-B during any transition to ADS-B adoption, or you will just
see other early adopters.

You also need ADS-B ground station coverage for ADS-R: the relay
between 1090ES and UAT link layers so aircraft equipped with one type
of ADS-B receiver will see the signals from an aircraft equipped with
the other transmitter type. That is a USA only peculiarity. In Europe
for example it is 1090ES only.

One confusing point as well is some ADS-B *receiver* manufactures and
less than clear that their devices are not transmitters so while you
might see other ADS-B boxes (or transponders via TIS-B) they can't see
you. Sometimes there is an implied belief that the aircraft with the
receiver has a transponder.

The Alaska trials were UAT only AFAIK and compared to large areas of
no SSR coverage and subsidized installation of UAT devices it is not
surprising it had good results. The GDL 90 was basically developed for
those trials and is showing its age. Garmin has a much more
interesting traffic solution now in the 800 series which include
active transponder interrogation (i.e. a TAS/TCAD) system combined
with ADS-B via 1090ES over Mode S (and you can pull up Mode S TIS on
the same hardware if you want need to, not sure why you would). In
Europe there are interesting combined Flarm and ADS-B 1090ES receivers
like the Garrecht 1090-TRX and PowerFlarm (not yet shipping). The
glider and GA avionics manufacturers in Europe are focusing on 1090ES
for ADS-B since Europe has mandated Mode S transponders. I expect to
see a wide variety of 1090ES and UAT devices in gliders and GA
aircraft and ADS-R relay is goign to be an important issue. i.e. think
about ground station coverage in mountainous terrain and along ridges
etc. where you can't just assume the other guy has an "ADS-B" and you
will see him. I believe that some vendors are working on dual-band (UAT
+1090ES) receivers and that may be a good thing.

Extended squitter is really a term that applies only to Mode S
transponders and in that case is the message type that carries the ADS-
B transmission.

Darryl