Primarily for general aviation discussion, but other aviation topics are also welcome.
#1838416
Our GTX 330ES deals with GND and ALT automatically, and you can watch us taxi on FR24 etc. if you are sufficiently nerdy. So I assume that a Skyecho or similar would see us on the ground.
#1838417
PaulSS wrote:Of course, this is not just a SE2 problem and those who do similar with their transponders etc are just as guilty of providing nuisance warnings when they’re on the ground.


I think that it is now the case than your transponder should be on from the moment the aeroplane moves, no? Im sure Ive been given a squawk on the ground before.

Regards, SD..
#1838419
johnm wrote:Our GTX 330ES deals with GND and ALT automatically, and you can watch us taxi on FR24 etc. if you are sufficiently nerdy. So I assume that a Skyecho or similar would see us on the ground.

Yes it would, and that is why SD, after a discussion on their forum, suppresses warnings of such traffic according to a height/speed ruleset. There was nothing more distracting than getting constant multiple audio warnings when on final, triggered by aircraft holding at the threshold.
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#1838422
@skydriller You will, no doubt, have been given a squawk when on the ground. For most GA this will be primarily for use once in the air but suitably equipped ATC units can certainly use your Mode S ground mode to see you on their ground movement radar. The important bit here, as I understand it, is that ground mode doesn't transmit altitude and, therefore, your extended squitter will not be transmitting ADSB 'cos it doesn't have the full suite of info to do so. Because of this ADSB receivers don't get scared and give us nuisance warnings.

@johnm I think FR24 is using an MLAT feed to provide ground traffic (through Mode S ground mode)........or maybe it doesn't, having just read Graham's post above :?

I suppose another option would be for SE2 and similar, to not provide warnings below, say, 100'. Similar, in a way, to the way TCAS changes its modes from RA/TA to RA to no descent RA as you descend.

My 'air switch' works through a combination of speed and engine RPM from the EFIS to let the transponder (and ADSB) start doing its job. I know it doesn't chuck out ADSB on the ground because I've had to disable the air switch in the past in order to be received on another person's ADSB In device when he was testing it.
#1838433
Sky Echo doesn't have a worldwide ground height map, so doesn't know "height".

ADS-B has a "ground" flag that gets broadcast when the transponder / SkyEcho thinks you are on the ground. Sky Echo broadcasts this when you are below the set speed. Transponders will broadcast this when you set Ground Mode or if you have a weight on wheels or airspeed switch trigger it. Mode-S Transponders will also respond to interrogations differently when on the ground, providing info such as aircraft width and transponder antenna location in the aircraft offset to allow a ground movement radar to provide accurate movement separation.

When ground mode is broadcast, EC devices will generally not try and provide traffic information on that aircraft.
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#1838437
Rob P wrote:
leemoore1966 wrote:.., we considered filtering on ground speed, but that is not useful for helicopters


I can't offhand recall any mid-air collisions involving a hovering helicopter :lol:

Rob P


:think:

Not a collision, but proximity of a C182 to an air-taxiing Sea King a possible cause of a fatal accident at St Mawgan, 2001:

https://assets.publishing.service.gov.u ... 501305.pdf

I never flew with a PAW nor any ADSB in nor out gizmo; one reason why I became disenchanted with our syndicate is that my suggestion that we invest in a PAW (after reports from the 1st or 2nd Rally when they had been used and praised) was voted down ('buy a personal one if you want'). However, I flew from Staverton for many years when the usual runway in use was 27, and for many of those years there was an available helipad very close at RAF Innsworth under the climbout. It may still be there at "Imjin Barracks", now home to the NATO ARRC. I have no idea whether helos there gave the Staverton ATCOs any warning of imminent lift-off; perhaps they did by 'phone or on VHF APP when Staverton circuit pilots would have been on TWR. Anyway, I certainly sometimes looked down and saw something on the pad with rotors turning, without TWR ATCO giving circuit traffic any warning. So perhaps ADSB-out from a helo on the ground with systems running could sometimes be useful to passing FW.
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#1838513
GrahamB wrote:
johnm wrote:Our GTX 330ES deals with GND and ALT automatically, and you can watch us taxi on FR24 etc. if you are sufficiently nerdy. So I assume that a Skyecho or similar would see us on the ground.

Yes it would, and that is why SD, after a discussion on their forum, suppresses warnings of such traffic according to a height/speed ruleset. There was nothing more distracting than getting constant multiple audio warnings when on final, triggered by aircraft holding at the threshold.
I used to get that at Popham as we have a PAW base station . My solution was to pull the audio cable out!
#1838646
@malcolmfrost
I used to get that at Popham as we have a PAW base station .


They've changed the logic in that now, Malcolm. SkyDemon etc know it's a ground station and you no longer get the warnings you previously did; as if it were an aircraft.