Author Topic: Aircraft Orientation Issues When Using Funke Transponders for ADSB Out  (Read 2199 times)

Admin

Hi Clive
What settings have you configured for the nmea output
You can find this under advanced settings

Brian, the 396 outputs much more than GPRMC, I wonder if funke have provided the correct info

I checked this from our ground stations too, and the DF17 has the correct data on 16/5

According to the Garmin manual
Always transmitted
GPRMC, GPGGA, GPGLL, GPBWC, GPVTG, GPXTE, GPRMB

hmm, is it really using this ....
GPVTG http://aprs.gids.nl/nmea/#vtg

Then there are optional choices

Thx
Lee
« Last Edit: May 17, 2021, 12:50:35 pm by Admin »

GeoffreyC

Is it possible for the RS232 converter to corrupt the signal somehow?
It shouldn't be, despite the circuitry at its heart its just a physical connector.  RS232 sends data in a serial manner with a ground and signal line into the transponder,  USB is Universal Serial Bus, 4 connectors, +5v, 0v, signal and signal ground.
There's no decoding/rewriting of the data packets being done, its at the signal layer.
Worth checking that the baud, error correction bit etc are set the same and match the Funke and PAW,   and maybe there's a problem with one device not being able to keep up so a different baud rate might help, but 9600 isn't exactly fast.
Geoffrey

CliveJ

Hi Clive
What settings have you configured for the nmea output
You can find this under advanced settings

Just the straight NMEA at 4800 baud.
Regards, Clive

Admin

OK, so according to the manual it will send the following

GPRMC, GPGGA, GPGLL, GPBWC, GPVTG, GPXTE, GPRMB

Thats quite a lot of messages for 4800 baud, at 4800 that is 600 characters per second
7 messages, which I think MUST be less than 80 characters, so 560 characters + '\r\n' per line=14

Brian, do you think Funke could be using these other messages ?
GPVTG is a track message

Thx
Lee

bnmont

Hi Lee,
I’m afraid I don’t know for certain. Michael at Funk’s has only mentioned the need for the GPRMC data set. Nothing else mentioned.
Would it be possible to build a beta with the GPVTG messages as well?
The Funke can do 9600bd

Regards Brian

CliveJ

Had to look them up....

GPRMC, Recommended minimum specific GPS/Transit data
GPGGA, Global Positioning System Fix Data
GPGLL, Geographic position, latitude / longitude
GPBWC, Bearing and distance to waypoint, great circle
GPVTG, Track made good and ground speed
GPXTE, Cross-track error, Measured
GPRMB, Recommended minimum navigation info

OK, so according to the manual it will send the following......Whose manual?

Regards, Clive




bnmont

I think that’s from the Garmin 396 manual

CliveJ

I think you are right, just been looking at it.
Doubt mine is set to anything extra but I'll go and have a look shortly.
The options to send extra data don't look like they would help with aircraft position and track which is all we need for the TXP?
Rather they are for using with other gadgets, waypoints, Routes, and to show status of the GPS and satellites.
If both can take 9600 baud maybe I'll move it up to that.

Reading the manual, whatever next.....

My GPS is connected to and works with an Dynon HSI with all the Nav stuff showing so maybe it has some extras being sent.
Heading to airfield for a look see, 

CJ

« Last Edit: May 17, 2021, 06:39:59 pm by CliveJ »

bnmont

Funky with 6.3 software can do 9600 bd

CliveJ

Went down the airfield and interrogated the Garmin.
It's a 196 so Black and White, I can update it so i've never thought of changing it.

It's set to 4800 and the 9600 is only available if you simplify the text it sends out so I didn't move that.
It's as Lee says so the message it's sending is as per his list which is from the manual, which obviously works.
It hasn't compromised my HSI or my autopilot so the Garmin is successfully sending to three units.
From what I've just read 232 was for a single link between two computers and as such doesn't guarantee multi drop but it obviously works in my case.

Given it seems to be doing the job for the Funke I'm going to leave it as it is.
Have also forwarded the info to Funke who replied 'we are talking to Pilot Aware'

So, looks like something needs doing with the PilotAware to supply the info that is missing (track made good), the rest seems ok?

Regards, Clive


CliveJ

ADMINS: The end of this string is really about what a Funke transponder is transmitting when it gets its GPS information from the PAW unit as opposed to another GPS. As such maybe it needs to be re-titled? Or seperated?

So what happens next regarding the, what looks like, lack of track being passed over?
My tests suggest the PAW unit isn't sending the same information as a regular GPS (in my case a Garmin 196).
Is this something that can be changed within the PAW unit?
Or am I understand the functionality incorrectly?

Regards, Clive

bnmont

Hi Clive
Agree that last posts should really be moved. I have ground tested a beta software release which Lee produced. This has extra message types Including GPVTG and now appears to be performing correctly. No flights yet just a short ground run.
Funke keep saying that the transponder only needs the GPRMC data though.

Regards Brian

exfirepro

Hi Clive,

Resolution of this problem is obviously at a delicate stage and as a beta test is underway it would be inappropriate for me to comment in any detail on a public forum until testing is complete.

What I will say is that if Lee’s findings are correct, the issue could well apply to GPRMC messages from other ‘regular GPS sources’ not only from PilotAware - (though it obviously doesn’t apply to your Garmin). If so, and as it is obviously not an issue for other transponder manufacturers such as Trig, the final solution may well be a further software adjustment by Funke.

In the meantime, my advice would be to continue with your Garmin feed, - though if you want to get involved in the testing, I’m sure Lee would be happy to provide you with a copy of the PilotAware Beta Software Brian is using to try out.

Best Regards

Peter
p.s. I agree it would be appropriate to split the latter part of this to a separate thread - probably from Brian’s post (Reply#18 on Page 2)
 
« Last Edit: May 23, 2021, 10:47:31 am by exfirepro »

CliveJ

Sounds good Peter and Brian.

I'm happy to help if I can though not keen to get under the panel again for a while. Where I have made the option to change over GPS NMEA feed easier it's not flicking a switch. I have made the change back to The Garmin semi permanent so I don't need to revisit to tidy it up.
There is one more PAW at my field but the ASDB exchange seems to be a good test tool.

I was testing Safe Skies yesterday whilst being monitored by another user on the ground, seemed pretty seamless if you have 3 or 4G, the track shows when I was turning the Funke on and off. No other aircraft about so couldn't check the collision warnings, I'm going to give that a go when I'm not the only aircraft flying in North Norfolk.
https://globe.adsbexchange.com/?icao=406436&lat=52.715&lon=1.543&zoom=11.1&showTrace=2021-05-22

Regards, Clive


bnmont

Re: Aircraft Orientation When Using Funke Transponders for ADSB-Out
« Reply #44 on: May 29, 2021, 05:03:59 pm »
Looks like my Funke is now doing what it should. This is a Beta version first flight Funke getting its messages from PAW.
https://globe.adsbexchange.com/?icao=406cb1&lat=52.169&lon=-0.316&zoom=12.9&showTrace=2021-05-29

https://aircrew.co.uk/playback/groundstations/?ICAO=406cb1&RxType=ADB&adbVariant=*&Station=*&start=1622289600&end=1622300400

Thanks Lee