PowerFlarm “Own Transponder Detection" Rate

I’ve been trying to get the rate of "own transponder detection" by my PowerFlarm Core as low as possible. Nothing I’ve done has improved it beyond roughly every 10 minutes, on average. Sometimes it’s much worse, showing up almost constantly. Turning off PCAS isn’t really an option for me, so I’d like to know if it’s possible to get a lower false alarm rate.

QUESTION - If you have a PowerFlarm with the PCAS function turned on, what false alarm rate are you getting? If the period is longer than 10 minutes, what did you do to get it (configuration settings, antenna placement, area you fly in)?

For reference, I’ve been working on this problem in both my old LS-8 (with a Mode S) and my new one (with a Mode C). Both ships used the same PowerFlarm configuration file settings, except for XPDR and MODESALT (both were set correctly for each ship). OWNMODEC was set to Aggressive in both ships. The PowerFlarm and transponder antennas were in the same position in both ships (glare shield and tail boom, respectively) and the PowerFlarm Core was the exact same unit for both ships, too.

-John, Q3

Not that I can help but I haven't experienced that problem with my
Stemme. My transponder antenna is on the under side of the carbon nose
bowl and the PF antennae are on top of the glare shield. Maybe the
carbon blocks the transponder signal so the PF doesn't "see" it directly.

On 7/12/2017 8:34 AM, John Carlyle wrote:
I’ve been trying to get the rate of "own transponder detection" by my PowerFlarm Core as low as possible. Nothing I’ve done has improved it beyond roughly every 10 minutes, on average. Sometimes it’s much worse, showing up almost constantly. Turning off PCAS isn’t really an option for me, so I’d like to know if it’s possible to get a lower false alarm rate.

QUESTION - If you have a PowerFlarm with the PCAS function turned on, what false alarm rate are you getting? If the period is longer than 10 minutes, what did you do to get it (configuration settings, antenna placement, area you fly in)?

For reference, I’ve been working on this problem in both my old LS-8 (with a Mode S) and my new one (with a Mode C). Both ships used the same PowerFlarm configuration file settings, except for XPDR and MODESALT (both were set correctly for each ship). OWNMODEC was set to Aggressive in both ships. The PowerFlarm and transponder antennas were in the same position in both ships (glare shield and tail boom, respectively) and the PowerFlarm Core was the exact same unit for both ships, too.

-John, Q3

--
Dan, 5J

Thanks, Dan. At least I know someone has found a way to get to a point where there are no PCAS false alarms! But I really have to ask - do you see any PCAS alerts for other aircraft?

-John, Q3

On Wednesday, July 12, 2017 at 11:54:11 AM UTC-4, Dan Marotta wrote:
Not that I can help but I haven't experienced that problem with my
Stemme. My transponder antenna is on the under side of the carbon nose
bowl and the PF antennae are on top of the glare shield. Maybe the
carbon blocks the transponder signal so the PF doesn't "see" it directly.

On 7/12/2017 8:34 AM, John Carlyle wrote:
I’ve been trying to get the rate of "own transponder detection" by my PowerFlarm Core as low as possible. Nothing I’ve done has improved it beyond roughly every 10 minutes, on average. Sometimes it’s much worse, showing up almost constantly. Turning off PCAS isn’t really an option for me, so I’d like to know if it’s possible to get a lower false alarm rate.

QUESTION - If you have a PowerFlarm with the PCAS function turned on, what false alarm rate are you getting? If the period is longer than 10 minutes, what did you do to get it (configuration settings, antenna placement, area you fly in)?

For reference, I’ve been working on this problem in both my old LS-8 (with a Mode S) and my new one (with a Mode C). Both ships used the same PowerFlarm configuration file settings, except for XPDR and MODESALT (both were set correctly for each ship). OWNMODEC was set to Aggressive in both ships. The PowerFlarm and transponder antennas were in the same position in both ships (glare shield and tail boom, respectively) and the PowerFlarm Core was the exact same unit for both ships, too.

-John, Q3

--
Dan, 5J

Yes, I do see PCAS alerts. And, having read more of this thread, I
believe I'm suffering from this as well. I occasionally get a PCAS
alert at +00 altitude and on top of my location. I've looked like crazy
and never seen another aircraft that close so I guess I can assume that
I'm getting a false alarm, too. I'll look at my config file and see if
I left something out.

On 7/12/2017 12:08 PM, John Carlyle wrote:
Thanks, Dan. At least I know someone has found a way to get to a point where there are no PCAS false alarms! But I really have to ask - do you see any PCAS alerts for other aircraft?

-John, Q3

On Wednesday, July 12, 2017 at 11:54:11 AM UTC-4, Dan Marotta wrote:
Not that I can help but I haven't experienced that problem with my
Stemme. My transponder antenna is on the under side of the carbon nose
bowl and the PF antennae are on top of the glare shield. Maybe the
carbon blocks the transponder signal so the PF doesn't "see" it directly.

On 7/12/2017 8:34 AM, John Carlyle wrote:
I’ve been trying to get the rate of "own transponder detection" by my PowerFlarm Core as low as possible. Nothing I’ve done has improved it beyond roughly every 10 minutes, on average. Sometimes it’s much worse, showing up almost constantly. Turning off PCAS isn’t really an option for me, so I’d like to know if it’s possible to get a lower false alarm rate.

QUESTION - If you have a PowerFlarm with the PCAS function turned on, what false alarm rate are you getting? If the period is longer than 10 minutes, what did you do to get it (configuration settings, antenna placement, area you fly in)?

For reference, I’ve been working on this problem in both my old LS-8 (with a Mode S) and my new one (with a Mode C). Both ships used the same PowerFlarm configuration file settings, except for XPDR and MODESALT (both were set correctly for each ship). OWNMODEC was set to Aggressive in both ships. The PowerFlarm and transponder antennas were in the same position in both ships (glare shield and tail boom, respectively) and the PowerFlarm Core was the exact same unit for both ships, too.

-John, Q3
--
Dan, 5J

--
Dan, 5J

I have a mode C transponder and never had a false alert from my own transponder, not even once in the 1500 hours or so that I have with powerflarm.

Ramy

Wow, Ramy, sounds like you found the magic! Would you kindly share some details?
1. Contents of your PowerFlarm config file
2. Type and location of your Flarm antennas
3. Location of your transponder antenna
A lot of us would dearly love to be able to duplicate your amazing results.

-John, Q3

On Thursday, July 13, 2017 at 3:24:15 AM UTC-4, Ramy wrote:
I have a mode C transponder and never had a false alert from my own transponder, not even once in the 1500 hours or so that I have with powerflarm.

Ramy

I disabled mine for the Nephi OLC event, but would also like to have it actually work right. My old MRX PCAS was very reliable in this situation.

What I see is bursts of self alerts then a few hours of silence, followed by another spurt of warnings. Easy enough to identify due to the very short range and altitude less than 50'.

Maybe what we need is an option to filter out any PCAS target less than 1/2 km since by then a warning is not likely to help?

5Z

I had this problem. It means that your powerflarm configuration file is not properly set with your own transponder code. If properly set, it always ignores your own transponder.

On Wednesday, July 12, 2017 at 9:58:05 AM UTC-7, John Cochrane wrote:
I had this problem. It means that your powerflarm configuration file is not properly set with your own transponder code. If properly set, it always ignores your own transponder.

I'd hesitate to use the term "always".
Due to alerts of collisions with myself even after correcting a hex address problem, I have disabled Mode C alerts.
In this way I can continue to ignore the thing and use LookOutTheWindow.com unless something serious is happening. Mode C reporting seems a nuisance, especially in a thermal with other transponder equipped glider(s).
Jim

I don't think that's my problem, John. When I had a Mode S transponder I still got false PCAS alerts, even with the Mode S code being identical (as in, copied and pasted from the FAA site into the PF config, and then cross-checked with what the Trig 21 displayed). A Mode C transponder doesn't output the Mode S code, so the code doesn't help the PowerFlarm identifying my transponder signal. The Mode S code for my new glider that is in my PF config file is transmitted by the Flarm so my glider can be IDed by other Flarm users who loaded FlarmNet.

-John, Q3

On Wednesday, July 12, 2017 at 12:58:05 PM UTC-4, John Cochrane wrote:
I had this problem. It means that your powerflarm configuration file is not properly set with your own transponder code. If properly set, it always ignores your own transponder.