Mode-CS (Beta)

[Admin]

I am continuing to get spurious returns, I believe, on the latest version.

I am using the '+Filter' option, and have '+-2000'' and 'Short Range' set. Descending from FL100 over mid-Wales today I was getting an intermittent warning of Mode C traffic either 100' or 200' below me most of the way down.

Unfortunately I didn't save the settings page nor track logs.

Hi Graham
You say warnings below ar 100-200 Ft.
This seems strange, if the filter was not working, and you were descending, I would expect your own transponder to appear above, not below you.

Are you able to compare the reported barometric altitude of PilotAware versus your transponder.

Also a look at the tracks would help
Thx
Lee

[grahambaker]

Hi Lee, the PAW box is in the aircraft 7 miles away now, and I won't be going there for another two weeks as I'm off to the US on business tomorrow morning! I do remember noticing on the ground that the PAW QNH was 1032 - exactly that as given by both Sleap and Welshpool over the RT.

Next time I fly, if I see the same symptoms I'll take some screen shots. Remind me again how I save the Track Logs?

[Ian Melville]

Track logs are saved automatically, and can be downloaded from the logs page in PAW. If PAW is fixed in the aircraft, and you have the latest software, then you can sync it to a pen drive for viewing back home.

[grahambaker]

Email with some logs sent to Lee. I managed to sneak to the airfield and download them.

[exfirepro]

Well done Graham. The track logs will certainly help Lee get to the bottom of things.

Regards

Peter

[Admin]

Hi Graham,

I have taken a look at the logs.
I agree I think this is seeing your own transponder - that is strange, and does look like an issue
we had seen on an older release.

Can you firstly confirm which release you are using ?
Also what your Mode-CS selection settings are ?

I guess this could be a while, as you mentioned you were out of the country on business

Thx
Lee

[grahambaker]

Hi Lee, I snapped this on the iPad when I downloaded the logs. It's not from the date of the flight, but nothing changed in the set up since.

[Admin]

Thanks Graham, OK, I think I see what is happening here 

The current algorithm tries to 'learn' that this is your transponder using a set of heuristics about power, and relative height.

The data you collected is very good, I think I can use this to try to refine the algorithm.
I also need to add more logging, because it would appear that your transponder signal (received by PilotAware) is below the threshold
defined as identifying your own transponder.
In order to diagnose this I need additional logging

Thx
Lee

[grahambaker]

Hi Lee,

When I get back from the US I'll collect and send you some more.

Perhaps the low signal level is due to relative positioning of the PAW (coaming) and the transponder antenna (further back under belly of aircraft). When I gather some more track data, I'll move the PAW to a different location, perhaps by the rear pax side window.     

[JonBoy]

On the ground and just playing - with it set to mode c/s (But NOT the filter option) would I expect to always see a return from my own mode C transponder?   Because I'm not seeing mine at all, never seen it in fact.

Also, daft question - if you want to use the option of seeing mode c/s traffic, why would you ever select the option not to use the filter?  Surely if you do have your own mode c or s transponder then that's what you want - or if you don't have your own mode c or s transponder then it wouldn't make any difference to you whether the filter is selected on or not...??

[Admin]

Hi Jonathan.

On the ground and just playing - with it set to mode c/s (But NOT the filter option) would I expect to always see a return from my own mode C transponder?   Because I'm not seeing mine at all, never seen it in fact.

Yes you should see your own, try taking a look at the traffic page to see if it is listed.
Also, remember it will only be seen when it is interrogated, so may not being interrogated

Also, daft question - if you want to use the option of seeing mode c/s traffic, why would you ever select the option not to use the filter?  Surely if you do have your own mode c or s transponder then that's what you want - or if you don't have your own mode c or s transponder then it wouldn't make any difference to you whether the filter is selected on or not...??

No this does make a difference, so if you have no transponder - do not select the filter.

Thx
Lee

[AllanBirt]

Hi Lee
I'm also seeing myself with Mode S/C either 100ft above or below. I'm using your latest version that you have updated for RB Pi2 v1.2. Hopefully you will have a fix shortly, this is the first flight since upgrading my hardware.

Just for info I have a Trig TT21 Transponder with ADSB out with is getting my GPS from my MGL Explorer lite
Allan

[Admin]

Hi Lee
I'm also seeing myself with Mode S/C either 100ft above or below. I'm using your latest version that you have updated for RB Pi2 v1.2. Hopefully you will have a fix shortly, this is the first flight since upgrading my hardware.

Just for info I have a Trig TT21 Transponder with ADSB out with is getting my GPS from my MGL Explorer lite
Allan

Hi Allan
You say mode s/c. Do you mean both ?
Mode C - possibly, mode S are you sure ?
Can you supply the track of your flight where this issue occured

Thx
Lee

[Paul_Sengupta]

I flew yesterday and I was getting quite a few alerts on myself...mostly 100ft out, but at one point I got it 200ft out. I have a Mode C transponder.

[Admin]

I flew yesterday and I was getting quite a few alerts on myself...mostly 100ft out, but at one point I got it 200ft out. I have a Mode C transponder.

Hi Paul,
Was this during a climb / descent ?
Also, can you please provide he track file so I can investigate.

thx
Lee