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Old July 21st 14, 01:07 AM posted to rec.aviation.soaring
Darryl Ramm
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Posts: 2,403
Default I need help with PowerFlarm problem

On Sunday, July 20, 2014 4:20:59 PM UTC-7, Andy K wrote:
On Saturday, July 19, 2014 8:58:17 PM UTC-4, Darryl Ramm wrote:

On Saturday, July 19, 2014 5:19:57 PM UTC-7, Andy K wrote:




On Saturday, July 19, 2014 6:48:44 PM UTC-4, Darryl Ramm wrote:








On Saturday, July 19, 2014 1:06:38 PM UTC-7, Andy K wrote:
















Here is my configuration:
































PowerFlarm brick and Trig T22 mod S transponder. PowerFlarm configured with the transponder code to disregard it.
































































I get constant notifications of my own transponder; yesterday probably 100 times, not kidding. I will have to unplug LX9000 from the PowerFlarm as it is not possible to use it as the PowerFlarm warnings just take over the screen.
































































I have had this problem with ASG-29 and ASH-26E. In the first glider the PowerFlarm antenna was set up high over the glare shield in the second glider (the 26E) the PowerFlarm antenna is in the fuselage cone as front part of the fuselage does not have any carbon. The 26E has a transponder antenna at the gear door. There is no carbon interference between the two antennas. I have good coverage as proven by experience flying with others.
































Any help how to get to the root cause of this problem is appreciated. I can accept sporadic alerts but yesterday it was simply unacceptable.
































































On the other hand it was really nice to see a couple of twins with ADS-B out doing big circles around me.
































































AK
































An issue here is that you can correctly set the type and ICAO ID of your transponder in your FLARM so that the Flarm will ignore the Mode-S replies of that transponder. However every Mode S transponder also has to reply to Mode C interrogators, and when your Trig TT-22 does that, there is no ICAO address included in that transmission and your PowerFLARM then has to reply on altitude correlation (and RF power) to guess this is the local transponder. But it should be pretty good at doing this becuase it should be reading the Mode-S altitude from the transponder. You might get into problems where you have very spotty interrogations, or mostly Mode-C only interrogations (e.g. if below say SSR radar coverage and being interrogated by older GA TCAD systems which issue Mode C only interrogations). If you are anywhere near busy airspace/civil or military SSR radar covered airspace that issue should not happen.
































Double check you have *all* the PowerFLARM settings correct including transponder type (must be mode S.. that gets the PowerFLARM using the transponder's own altitude) and have the correct ICAO code entered without any base conversion errors.
































Check all your cables and cables, try swapping the FLARM 1090MHz antenna/cable with known good ones.
































Earlier ASH-26Es had fairly poorly installed transponder antennas right behind the gear doors. If yours is like that you really should install the antenna from behind the engine bullhead (requires engine removal) as described in the current TN. I'd do that even if a current install right behind the gear door appeared to be OK with biannual transponder tests. Use new RF cable and put the TT-22 RF box as close as you can to the antenna... ideally mounted remote behind that engine bullhead.
































I don't understand what you mean by "carbon interference". I'd be surprised but it might be possible there is too much carbon/ground plane obstructing the transponder signal to the PowerFLARM.
































Are there warning happening in flight at decent altitude? Or when low or on tow (does the tow plane have a transponder?). Are there any nearby transponder equipped gliders? Where exactly are you flying/at what altitude (covered by what SSR facility etc.).
































If you can't track down anything I would try borrowing a PowerFLARM Portable from somebody to do an A/B test with.
















Darryl,








thank you for your post. I saw the same issue with this PowerFlarm box in my ASG-29 where Transponder antenna was installed in the fin by Schleicher. Between the 29 and the 26E the only thing common was the PowerFlarm. In the 29 the PF antenna was mounted at the top of the glare shield.
















In the ASH-26E the transponder antenna was installed behind the gear door by Schleicher. I will take a look at the location.








In regards to "carbon interference" I don't see any in terms of direct line.
















Strangely enough I flew the ASH early June and I did not observe as many false warnings. I don't remember this being such a big deal this season until yesterday when it became impossible to deal with. I did not fly the 29 this year but in that glider I don't remember the false warnings to be constant. Yes they were annoying but I could deal with them.
















Half of the area I flew in yesterday had good radar coverage the other half was spotty. I did not see big difference between PF noise level. I flew most of the day alone and there were no other gliders around. The false warnings where happening probably once a minute or so.
















I will go over the PF configuration? Darryl, can you share with me your configuration file? I know I would need to change the transponder address, but I wonder about other parameters and their interaction e.g. bugs in PF software. There might be some specific configuration that I have that is causing these issues.








AK








My PowerFLARM is sitting in its box unused as is my glider. Just post your config file here. And the ICAO address you think is correct for your glider.








The false warnings were happening mostly when you believed you were inside or outside of SSR coverage? Exactly where and at what altitude were you flying when you had most false reports.




Here is the dump written to a file by PF Core

################################################## ######################

# Auto-generated file, don't edit!

################################################## ######################

2,PowerFLARM-Core,523,SWVER=3.40,REGION=USA,ID=AD3868,CALLSIGN= N951AK,ACFT=1,CAP=OBST;RFB;TIS;IGC;ENL;DLED;USBH;D P2;XPDR,LIC=AUD:0;ENL:0;IGC:1;RFB:1;TIS:1,XPDR=2,C AL57=372



As you can see the transponder code in PF is correctly set to AD3868. The transponder is also set to AD3868. It is Trig T22.



How do you get a full configuration file dump in PF that includes alert distance and vertical separation?



AK


And importantly you have Transponder type set to 2 for Mode S, which getting wrong is a cause of these type errors as well. The first mention of XPDR in the dump just means the 109ES receiver licenses capability is enabled.

I can't recall the dump options, are you using "$debug_out,fat,all,all", you can also just your riginal config file.