On Sep 29, 6:20*pm, "Mike Schumann" mike-nos...@traditions-
nospam.com wrote:
There is a lot of concern in the US that the Mode S bandwidth is too limited
to support universal deployment in busy airspace like Chicago, Atlanta, New
York.

This is one reason that the FAA has selected ADS-B UAT instead of the Mode S
based extended squitter technology for general aviation users in the US.

Mike Schumann

"cfinn" wrote in message

...

An interesting article just appeared in Aviation Ebrief:
"Holland's trial of Mode-S transponders led to a requirement that all
aircraft operating within Dutch airspace be equipped with the
transponders. However, the ATC system was overwhelmed by data from the
Mode-S transponders, and now all aircraft flying below 1,200 feet are
required to keep the transponders on standby."

Here's a link to the full article:
http://www.ainonline.com/news/single...mode-s-rule-pr...

I wonder how much testing and simulation has been done for busy US
terminal areas?

Charlie



What appears to have happened in the article about Schiphol is the
system/operators were just overloaded with information. If the article
is to be believed sounds just like poor planning. That is different
than the fundamental design type arguments about Mode S capacity that
Mike is referring to. The interest there is really ADS-B over Mode S
(aka 1090ES) or over UAT. The Schiphol deployment is just the European
mandated Mode S surveillance, not a full ADS-B deployment. There is
disagreement between the Europeans and the US on Mode S directions and
long term Mode S capacity. The Europeans basically believe Mode S will
evolve to handle capacity concerns and pushed ahead that way. On one
level they are getting things to happen. Products like the Trig TT21
which we get now over here is us benefit from European regulations
pushing Mode S innovation. The FAA's more ambitious goals and therefor
longer timeframes for ADS-B and Nextgen mean its going to be a while
until we see what really happens here. One possibility is thanks to
Europe Mode S deployments and the driver that has on products that
Mode S and 1090ES will be more prevalent here in the GA fleet than the
FAA envisioned. And after all ADS-B does not replace the need for a
transponder for TCAS avoidance and so basic Mode S transponders are
likely to be used in the GA fleet for some time. The interesting
question is how ADS-B integrated. And UAT has the promise of extra
data (FIS-B) vs. 1090ES. We'll have to see what happens.

Bottom line for now is, especially if you fly in areas of airline/fast
jet traffic, a transponder is likely a good investment. And if you fly
near Reno *please* use one. A Mode S transponder having the benefit
over a Mode C of having a greater than ~ 10 year life by surviving the
USA Mode S requirement.


Darryl