On Aug 10, 1:31*pm, Mike Schumann
wrote:
On 8/10/2010 2:22 PM, noel.wade wrote:



On Aug 10, 12:16 pm, Mike
wrote:

The problem with PowerFlarm is that it does not include ADS-B Out. *As a
result, it doesn't reliably receive any ADS-B in traffic data from a
ground station. *If this was a true ADS-B In and Out solution, it would

Mike - Weren't you just debating about flying out of range of ground
stations, when talking about transponders? *ADS-B from ground stations
falls into the same category.

In close proximity, I would expect ADS-B Out from another aircraft to
trigger my powerFLARM (ADS-B In) solution directly; no need for a
ground station relay!

--Noel

If the other traffic is equipped with ADS-B UAT (the FAA recommendation
for GA), and you our not within range of a ground station, PowerFLARM
will not see him.

--
Mike Schumann

Noel.

Read my earlier post in this thread that describes things needed for
ADS-R and TIS-B to work. The ADS-B dual-link design in the USA should
be a concern for us. The scary scenario is say running a ridge where
fully equipped UAT and ADS-B 1090ES just will not "see" each other
outside of GBT (ground station coverage). The GBT coverage will be
pretty impressive compared to say current SSR coverage but is just not
necessarily intended to say provide low level or close to terrain
coverage in places we might care about. This is one reason I don't
believe ADS-B technology alone in the USA can meet our needs until
somebody develops a dual-link layer receiver. Alternately different
locations might adopt UAT or 1090ES technology. I suspect what will
really happen shorter term is people will adopt PowerFLARM and rely
mostly on the flarm-flarm protocol to provide help with that type of
ridge running scenario and use the ADS-B stuff more for visibility of
GA and airline traffic (i.e. think of the ADS-B receiver stuff more as
a fancy enhancement of current PCAS capabilities).

The dual-link issue also affects the ability to track other gliders
over long ranges, that will work fairly well (and an interesting/
useful capability of ADS-B in general) if both gliders are on the same
link layer, but if one is a UAT and the other is on 1090ES the ground
infrastructure won't perform ADS-R unless the gliders are within each
other's service volume or the service volumes of similarly equipped
aircraft (I believe +/- 3,500' and 15 nm range). So your glider
buddies may appear and disappear off the traffic display at times.

Darryl