Mode-CS (Beta)

[peteD]

Hi,I have mode S txpdr with ADSB out.

PAW is set to "Mode-CS (Beta)" with the correct Hex -ID.

I noted the other day intermittent an  "red circle"(SD) warnings with no ID, at or near my level. Nothing seen(!) so presume this must be me. I know this is beta, just wondering if this is "normal" at present?

Thanks
Pete

[exfirepro]

Hi Pete,

The filtering for ADSB and Mode S is done from your 'Hex Code' which you say you have entered correctly into 'PAW Configure'. You should also set your PAW 'Mode C/S Select' to 'Mode C/S + Filter (Beta)', otherwise it might still react to the Mode C (altitude) part of your Mode S transmissions. It is likely this is what has happened in your case. The other possible explanation, if you are near a major CAT airfield, is that the system might be reacting to the Mode C component of the transmission from a high power CAT Mode S or ADSB signal.

Hope this helps

Regards

Peter

[peteD]

Hi, Thanks, I had used mode c/s beta because that is what the instruction manual(page 46) implied for a mode s txpdr.
So are you saying that because it's mode s + adsb, I need the additional filter? Will give it try!
Thanks
Pete

[exfirepro]

Hi Pete,

Its because of the way PAW processes Mode C. If you are using the Mode C receive option with a Mode C or Mode S transponder you need to use the filter, in your case to ensure that the system doesn't inadvertently respond to the altitude transmissions from your Mode S.

I will have another look at the Operations Manual and if necessary have it amended.

Regards

Peter

[Admin]

Hi All,

A Mode C or Mode S transponder will respond to a Mode C interrogation, so under these circumstances you need to select the 'filter' option on PilotAware, otherwise your own Mode C will be reported.

Thx
Lee

[peteD]

Ok, thanks, I think the instruction manual (page 46)needs amending.

So out of interest, when is the mode c/s beta setting used?
Groundstation/no transponder?
Thanks
Pete

[exfirepro]

Hi Pete,

Yes, you would use the Mode C/S (Beta) setting if you wish to detect Mode C and S transmissions, whether as a ground station or in the air, but don't yourself have a transponder. (ADSB out of course still has an active Mode S transponder, so you also need to use the filter).

The '(Beta)' reference by the way is just a reminder that the Mode 'C' detection software is still technically 'under development', but was released (early) because about 40% of all transponders in the UK are still reckoned to be Mode 'C' and consequently lots of our pilot users were asking for Mode 'C' detection. Unfortunately, compared to Mode 'S' transmissions which can be fairly easily identified from the 'Hex' code, Mode 'C' is a far more difficult beast to deal with, though from all reports the system seems to be working well, though we still need to do a bit more work on audio alerts from bearingless targets in general.

Regards

Peter

[Paul_Sengupta]

I've got the filter on and I occasionally get Mode C alerts for my own aeroplane when I climb or descend.

[Admin]

I've got the filter on and I occasionally get Mode C alerts for my own aeroplane when I climb or descend.

Hi Paul,
In the next release, something was added to handle this particular case, so be interested to see if you still see this issue after the next release

Thx
Lee

[peteD]

Any Idea when the next release may be

[Admin]

Any Idea when the next release may be

Hi Pete
Next release is imminent

Thx
Lee

[Keithvinning]

Pete
We will also change the instruction manual. Thanks for pointing this out. Feedback is always welcome
Keith

[Robski]

...about 40% of all transponders in the UK are still reckoned to be Mode 'C'...

Sounds like a low estimate to me!

[exfirepro]

...about 40% of all transponders in the UK are still reckoned to be Mode 'C'...

Sounds like a low estimate to me!

Hi Rob,

This was the best estimate we could find when we did our initial research. I would be happy to be corrected if you can point me to a more reliable source.

The point I was trying to make was that even if 'only 40%' of U.K. transponders are mode 'C', this clearly supports the development of PilotAware to detect such a major traffic group.

Regards

Peter

[rogerabc]

Evening all,

I still receive many spurious airborne alerts that seem to come from my own mode c transponder & this undermines the value of other warnings.
Hex code is set on the config page although of course my mode C transmissions do not include any hex code.
Mode-CS+Filter(Beta) is also set.

I downloaded the tracks for post flight analysis but the post processor doesn't tell me anything about mode C traffic - it would be useful to reconstruct the traffic table from this file - can that be done?

To be frank, whilst most appreciative of all your efforts, I'm not interested in icing like the radar display until basic functionality works better. Spurious warnings are like crying wolf.

Any suggestions most welcome.