Author Topic: PAW not seeing Skyecho  (Read 675 times)

jbone

PAW not seeing Skyecho
« on: January 20, 2021, 03:00:05 pm »
Hi,  I just bought a Skyecho and my PAW device isn't detecting it.  I would be grateful for an opinion on whether the problem lies with PAW or Skyecho please.   

I have configured the Skyecho for a Cub (G-BRIL) and it definitely has the reg and HEX code for the Cub set up correctly (lots of screenshot and Whatapp videos with Harry M to confirm that).

The PAW in the RV in the hangar 10 yards away is not seeing the Skyecho (and the PAW is definitely not set up with the same HEX code/registration) .  The PAW is seeing an ATOM groundstation 50 yards away (as well as other traffic) and the groundstation is seeing the PAW in the RV.   Both aircraft have really good GPS signals becuase the hangar roof is cement asbestos.  Please can you guys look at the screenshots from the PAW and tell me if anything is wrong?

Also, the ground station is not seeing the Skyecho either.   So, I'm pretty sure this is a Skyecho issue, but I want to double check with you guys first please before I return it to Harry M.

Thanks, John

 

jbone

Re: PAW not seeing Skyecho
« Reply #1 on: January 20, 2021, 03:01:26 pm »
More screenshots from the PAW

jbone

Re: PAW not seeing Skyecho
« Reply #2 on: January 20, 2021, 03:02:27 pm »
Screen shot of the ground station, which can see the PAW in the RV but not the Skyecho in the Cub

GrahamBaker

Re: PAW not seeing Skyecho
« Reply #3 on: January 20, 2021, 03:10:16 pm »
Are you sure that the SE2 is being seen by anyone else.

If two distinct PAW set-ups re not seeing it, it smacks more to be that the problem lay with the SE2.

It is set to transmit, isn't it?

jbone

Re: PAW not seeing Skyecho
« Reply #4 on: January 20, 2021, 03:23:46 pm »
Graham,

Yes, it the Skyecho is set to transmit, that was the first thing Harry M's checked.   Since this is the PAW forum, I wasn't going to commit the sin of uploading a Skyecho screenshot.    :)    Here is a further screenshot of the setup of the PAW in the RV. 

thanks, John

PaulSS

Re: PAW not seeing Skyecho
« Reply #5 on: January 20, 2021, 03:32:09 pm »
Is there a flight detect 'switch' on Sky Echo? If so you would have to bypass this to make it think it's in the air and, therefore, start transmitting.

This is just a suggestion as I am not au fait with the SE.

jbone

Re: PAW not seeing Skyecho
« Reply #6 on: January 20, 2021, 03:47:15 pm »
Graham,  no there isn't.   There is a field  on the setup screen to insert the stall speed of the aircraft (so it knows whether it is on the ground or in the air), but Harry M's assure me it should be transmitting all the time.  I'm glad I bought it from them, they really are a first class outfit,  Thanks, John

Admin

Re: PAW not seeing Skyecho
« Reply #7 on: January 20, 2021, 04:05:49 pm »
Graham,  no there isn't.   There is a field  on the setup screen to insert the stall speed of the aircraft (so it knows whether it is on the ground or in the air), but Harry M's assure me it should be transmitting all the time.  I'm glad I bought it from them, they really are a first class outfit,  Thanks, John

Hi John
I think Harry M needs some educating  ;)
I am positive that there is a field in the SE2 whereby the speed threshold, stops the unit from emitting, and hence cannot be detected

From the SE2 manual
Quote
8.3.12 Air/Ground Threshold Speed VSO (knots)
This parameter allows the SkyEcho 2 to automatically switch between
airborne and ground modes, which affects reception by other ADS-B
receivers
. Enter the stall airspeed (in kts) of the aircraft in landing
configuration. (0-999 knots).

We should start charging for support of other suppliers products  :P

Thx
Lee
« Last Edit: January 20, 2021, 04:09:48 pm by Admin »

PaulSS

Re: PAW not seeing Skyecho
« Reply #8 on: January 20, 2021, 04:43:35 pm »
I agree. If you put 0 into that field then it should (I believe) think it's flying and, therefore, start chucking out ADSB.

Maybe HM are getting confused with the different responses made by Mode S transponders whilst on the ground/in the air. That could affect the price of fish if this was ADSB via the extended squitter of a Mode S transponder but as Sky Echo is just an ADSB transmitter/receiver then it should only need to know if it's airbourne or not in order to start zapping the airwaves. That, I think, is the point of their stall speed 'switch'/air 'switch'.

exfirepro

Re: PAW not seeing Skyecho
« Reply #9 on: January 20, 2021, 04:47:47 pm »
Hi John/Graham/Paul/Lee,

I'm also not an 'Expert' on SkyEcho2, but in view of my previous experience with SkyEcho1, and PAW Testing in general, I am not at all surprised at your findings.

I don't have a SkyEcho2, but have had a SkyEcho(1) since they first came out, which I used extensively at the time for testing. I also know several others who have SE1s. In my experience, it is not at all unusual for nothing to be received from SkyEcho (1 at least) when it is not actually 'in the air' (even when the unit is 'moving' - see below).

When I first got my SE1, I was as you will imagine, keen to try it out, so charged it and after reading through the 'Manual' and doing the initial programming input, powered it up at home in my living room (inside the EGPH CTR), but couldn't see anything from it at all on two separate 'test' PAWs, despite the SkyEcho reporting a solid GPS fix. On further investigation, I found the SkyEcho 'Vso' setting (basically minimum landing or 'stall' speed as reported by Lee). I therefore tried setting the Vso to varying speeds - but even with it right down to '0' Knots, there was still no sign of any transmissions from the SE1. I then tried putting the unit in my car and belting round the local bypass at speeds up to 70 mph, with Vso set to varying speeds between 0 and 40 Knots, but this also gave no indication whatsoever that the unit was transmitting. My conclusion therefore was that there must also be some sort of tie-in with a minimum height above ground, climb rate or whatever before the SE starts to transmit, but nothing like this is mentioned in any uAvionix documentation I have seen and the only 'confirmation' I have (from subsequent testing), is that my SkyEcho1 certainly transmits when in a plane in the air (though I can't legally use it in my own as I already have ADSB-Out via my transponder).

Thinking further about this, it makes sense - after all the authorities wouldn't want people randomly powering up SkyEchos and gaily transmitting 'aircraft positions' on the 'official' 1090MHz band when the unit isn't in an aircraft in the air - (or in my case even in an aircraft). None of this however (apart from the 'Ground Mode Only when below Vso') is mentioned in the uAvionix documentation, or explains why I could never get the unit to transmit when still on the ground but well above the selected Vso. It would certainly be worth an e-mail to uAvionix Support to ask them to clarify the position.

If you find anything out, please let us know.

Best Regards

Peter

p.s. Not an 'expert' on Ground Mode either, but previous exhaustive testing in the vicinity of my local airport certainly seems to indicate that CAT traffic in 'Ground Mode' only transmits 'Mode-S' NOT ADS-B. If this is the case, then the SkyEcho obviously won't transmit anything in 'Ground Mode'.  Paul - any knowledge of this in relation to CAT?
« Last Edit: January 20, 2021, 04:57:47 pm by exfirepro »

PaulSS

Re: PAW not seeing Skyecho
« Reply #10 on: January 20, 2021, 05:49:08 pm »
Quote
Not an 'expert' on Ground Mode either, but previous exhaustive testing in the vicinity of my local airport certainly seems to indicate that CAT traffic in 'Ground Mode' only transmits 'Mode-S' NOT ADS-B. If this is the case, then the SkyEcho obviously won't transmit anything in 'Ground Mode'.  Paul - any knowledge of this in relation to CAT?

OOooohh, good question. I have never seen anything definitive written in any of our manuals but, then again, all the manufacturers are 'dumbing down' technical information to just the basic stuff. However, piecing together my 2 MBs of knowledge I think they do transmit ADSB on the ground.....BUT.

The reason I think they do transmit is because some airports can actually use ADSB for airport movements. At the moment this will almost exclusively be used for ground traffic because they have fewer requirements as far as certification etc is concerned. Most of the 'bigger' airports will use Mode S MLAT for ground movement of aircraft and this is often fed into the Air Traffic Management system, so flight plans, slot times etc are triggered. Being able to receive ADSB is definitely part of the plan to do away with expensive MLAT and use ADSB for ground control of aircraft (as well as the cars etc). In my logic, this must point to ADSB being transmitted by aircraft on the ground.

Now to my other thinking: when on the ground the Mode S transponders go into ground mode. This allows MLAT for ground movements but it doesn't transmit some of the information, namely altitude and, I don't think, speed. They're simply not needed and, with the altitude showing in ground mode, it helps airbourne traffic TCAS systems to not trigger false warnings to the landing traffic about the guy waiting abeam the threshold. So I think the ADSB squitter is still doing its job but, without altitude and speed, you're not going to see it on your ADSB receiver.....I think. Maybe the ground movement ADSB receivers are set up to receive ADSB without speed and altitude and functions quite happily with a few missing things with $ signs attached.

Lots of conjecture, I know, but failing anything in the books saying "ADSB works on the ground" I'm afraid my opinion is just based on the diatribe above.

AlanB

Re: PAW not seeing Skyecho
« Reply #11 on: January 20, 2021, 06:41:42 pm »
Before you start sending anything back might I suggest that you either place the ADS-B antenna on PAW horizontally or remove altogether. I have done this on occasions when I suspect the receiver is just been saturated by the proximity of the transmitter which can occurs at the distances you mention in your post.

PaulSS ADS-B is used extensively to track ground vehicles moving around the airfield on the GMR especially around the taxiways and runway. Not much used made of Mode-S transponders on ground vehicles and certainly generally no link between the Flight Activations systems or stand management as generally that is done by other means.

40 years as an Air Traffic Engineer.
Europa XS Mode-S ADS-B out enabled.

jbone

Re: PAW not seeing Skyecho
« Reply #12 on: January 20, 2021, 07:59:14 pm »
Thanks everyone, especially Peter, because I recognise exactly the process you went through!    I will chuck this back at Harry M to ask uAvionix  what I should expect to see on the ground.   I suspect HM are mistaken to say I should see a signal straight out the box.   You have all confirmed it's nothing to with PAW.  Thanks again,  John

PaulSS

Re: PAW not seeing Skyecho
« Reply #13 on: January 20, 2021, 09:35:30 pm »
Quote
PaulSS ADS-B is used extensively to track ground vehicles moving around the airfield on the GMR especially around the taxiways and runway.

I think that's pretty much what I said but maybe I should have been clearer is what I meant by 'ground traffic'  :)

Quote
The reason I think they do transmit is because some airports can actually use ADSB for airport movements. At the moment this will almost exclusively be used for ground traffic because they have fewer requirements as far as certification etc is concerned

exfirepro

Re: PAW not seeing Skyecho
« Reply #14 on: January 20, 2021, 10:38:19 pm »
Hi Paul / Alan,

Thanks both for the clarification. To be more precise, I was talking about aircraft in ‘Ground Mode’ rather than ‘Ground (Vehicle) Traffic’ per se. (Not sure whether Edinburgh uses Ground ADSB yet - my experience is mainly of them using radio to control and monitor ground movements, though I may of course be wrong).

My comments re the transition between ‘Ground’ Mode-S and Airborne ADS-B were based on lots of hours spent sitting in my car near the runways at Edinburgh Airport monitoring in and outbound traffic via PilotAware, while we were developing and testing the PAW Audio Alerts prior to release.

One of the things I found during those tests was that I could ‘see’ aircraft on the ground taxiing for departure and hear them on radio to Edinburgh Ground / Tower, but from the style of the PAW Audio Reports and the ‘Mode’ displayed on my PAW ‘Traffic Screen’, by far the majority of departing aircraft were clearly transmitting Mode-S during the take-off roll, and the transmission generally only changed to ADS-B as the aircraft passed overhead at about 500ft+ agl and probably 1/4 to 1/2 mile after rotating.

John,

As the customer, there is nothing to stop you asking the question direct to uAvionix via the Support section of their website. I found them very helpful on those occasions when I have contacted them in the past (not on this subject as I had already proved to my own satisfaction that SE1 definitely transmits once in the air).

Best Regards

Peter