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Old May 6th 13, 04:33 PM posted to rec.aviation.soaring
John Carlyle
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Posts: 324
Default PowerFLARM Transponder Alert Size

On Sunday, May 5, 2013 2:17:36 PM UTC-4, Andy wrote:
On May 4, 7:14*am, John Carlyle wrote:
Does anyone know the PowerFLARM transponder ADS-B and PCAS default alert size? This would be analogous to the Zaon MRX settings, like 5 mile radius with an altitude of +/- 2000 feet, inside of which it sounds a warning. I haven’t found a way to set the alert size in PowerFLARM, just the maximum range and maximum vertical range.


Dataport specification for sentence PFLAA may be worth a read. For
PowerFLARM core the warnings will, I assume, depend on what the
display system does with the available data.

The definition of PFLAA includes "PFLAA sentences are limited to other
aircraft with a horizontal distance of less than the configured
horizontal range (default is 3km) and a vertical separation of less
than 500m. Non-moving aircraft are suppressed." also included in
PFLAA (with yellow highlight) "Non-directional targets (transponder
mode C/S; protocol version 6 and higher) are only output as PFLAA
sentences."

The definition for PFLAU includes (with yellow highlight) "Only
directional targets (i.e., with a known relative bearing) are output
as PFLAU sentences."

Based on a quick read I assume that the alert volume is the same for
all target signal types and that only the range can be user defined.

Andy


Good catch, Andy, thanks for the tip. I agree, it appears that the alert "bubble" size is fixed, and that only the acquisition range and height can be changed.

I'm now trying to decide what my range and height limits should be. Seeing airliners 30,000 feet above me and 15 nm away is cool, but not particularly helpful. I guess I'll try a range of 9,500 m and a height of 900 m and see how that works in the crowded PHL-EWR area.

There's another problem I've got to solve, and that's the PowerFLARM PCAS function occasionally triggering on my own transponder. I've triple checked that the transponder's ICAO-24 hex code is the same as the PowerFLARM's aircraft ID, but every 5 minutes or so it displays a PCAS alert on myself. Turning the transponder off solves the problem, but that's scary where I'm flying. Maybe limiting the range and height will alleviate this problem? We'll see...

-John, Q3