Aircraft Registrations not properly showing on Sky Demon

[Gary Nelson]

I’ve recently noticed some traffic on my Sky Demon only shows as a “G” and the rest of the callsign is missing. Does anyone have any idea why?

NB On SkyDemon under “Navigation Options” I have the slide switch “Show Callsigns” set to on.

[Ian Melville]

A single G signifies a glider and is not part of a call sign. You have picked up a rebroadcast by an OGN/R station of a gliders FLARM signal.

[Gary Nelson]

but shouldnt the gliders full call-sign show?

[exfirepro]

Hi Gary,

As per Ian’s post, position signals from FLARM (or similar) equipped aircraft rebroadcast by an OGN-R Ground Station - which includes some GA aircraft as well as ATC and RAF Grob and Tucano Trainers, Gliders and Glider Tugs - are deliberately rebroadcast with a simple ‘G’ annotation to identify that this is a Ground Uplink Rebroadcast and not a directly received transmission from the aircraft in question. This acts as a reminder that you will only see the aircraft whilst both you and it remain in range of the receiving Ground Station.

The simple ‘G’ annotation also enables the system to comply with FLARM / OGN’s anonymity policies.

As per normal practice, the transmission includes the aircraft’s relative altitude.

Hope this helps clarify the situation.

Best Regards

Peter

[russp]

Saw this yesterday with a simple G and the icon in Easy VFR showed a rotary, which indeed it was .. how does SD / Easy VFY know it's a rotary and not a glider or other aircraft with flarm (or another system) as above if all it knows is it's an aircraft rebroadcast by a ground station . Another aircraft was shown with the glider icon and a G which was more what I was expecting. I've also learnt that G doesn't stand for Glider!

[exfirepro]

Russ,

The type of aircraft is determined by PilotAware by comparing the Hex ID (where received) against an internal database (which is also how it determines the Aircraft Reg). This info is then passed to the Nav systems in the form of a code which they can elect to use to determine what aircraft ‘type’ symbol to display. This system was developed in conjunction with major Nav System providers and worked very effectively with earlier versions of SkyDemon, EasyVFR and others.

Recent moves, for example to the use of the GDL90 protocol for data exchange, however, seem to have had a negative effect on the effectiveness of the aircraft ‘type’ display with some Nav systems. There are also issues due to ‘gaps’ in the aircraft ID database, which are outwith our control.

Hope this helps explain things.

Regards

Peter