Mode-C sporadic results

[Chris-TT]

Flew over to Alderney and back yesterday with Mode-C enabled. I have the hex code of the aircraft entered. Using Skydemon in the past it’s always removed the Mode-S aircraft hovering next to me (my aircraft), however on at least 6 occasions it showed my aircrafts registration, Mode-C and anything from -1.1 to -4.5 with the circle being green, orange, or red. Surely if it was my aircraft and the hex code was entered it shouldn’t be picking me up, and having such large variances in separation?

Thanks

[Admin]

Hi Chris

Flew over to Alderney and back yesterday with Mode-C enabled. I have the hex code of the aircraft entered. Using Skydemon in the past it’s always removed the Mode-S aircraft hovering next to me (my aircraft), however on at least 6 occasions it showed my aircrafts registration, Mode-C and anything from -1.1 to -4.5 with the circle being green, orange, or red. Surely if it was my aircraft and the hex code was entered it shouldn’t be picking me up, and having such large variances in separation?

Thanks

So I think there are 2 issues here, firstly why is your own transponder appearing.
That should not happen, and I will need to investigate.
can you please supply the track file for your flight ?

Mode-C, we think there may be an issue in Skydemon/PilotAware with the metres/feet conversion - we are investigating with Tim
but what makes you think the mode-C Circle was your own transponder ?

Finally what settings have you selected for the Mode C/S detection ?

Thx
Lee

[Chris-TT]

Hi Lee

Here is a link to the track files: https://dl.dropboxusercontent.com/u/674427/Track.zip

The reason I presumed it was my aircraft activating the Mode-C was because before the update, as long as it had the correct hex code for the aircraft it didn’t show on Skydemon for Mode-S. However during these flights my registration was showing next to the ring.

I was using Mode-CS(Beta), I have just noticed Mode-CS+Filter(Beta), I’m now guessing this was the one I should have selected to filter out my own aircraft?

Thanks

[Admin]

I was using Mode-CS(Beta), I have just noticed Mode-CS+Filter(Beta), I’m now guessing this was the one I should have selected to filter out my own aircraft?

Correct, although this is what is under development.
There is no diffinitive metod to filter the Mode-C because it contains no HEX code identifier.

Forgot to ask, what is your A/C ICAO code ?

Thx
Lee

[Chris-TT]

40216D

Thanks

[Admin]

40216D

Thanks Chris,
hmm, very very strange.
I have looked through the Track files, and I cannot find a single reference to 40216D, other than the debug logging.
I know this might sound annoying - you are absolutely sure you saw an A/C or Mode-S ring with 40216D or G-CLEA assigned ?

Thx
Lee

[Chris-TT]

Hmm weird, I was looking through the logs too, and couldn’t find a reference to the registration, or a similar reg. However I’m 99.9% sure Skydemon was displaying the aircraft registration. I’m probably not going to be flying for a week or two, but I’ll take a screenshot if it does it again!

[exfirepro]

Hi Chris,

I flew down to the LAA Rally yesterday from Scotland using a beta version of SD, which seems to have resolved the relative altitude anomaly. I am helping out on the PAW stand over the weekend so will speak to Lee about this and your 'ghost' mode C aircraft. As Lee says, mode C is still under development but was released early as so many people were desperate to get Mode C cover. 4WIW I was fairly happy with how it was working during my flight down yesterday.

Regards

Peter