Dynon GPS Support

[infobomb]

Hi DynonSupport,

I am helping rngaines with his AvMap IV EKP problem and emailed you some NMEA data before I registered for the forum. Please let me know if you need any more data and I'll be happy to go get it.

I am wondering if other AvMap users with current firmware are really getting good winds-aloft data. Our testing makes me think folks living where the magnetic variation is close to zero would see accurate winds.

We are using V 3.0 for our D-100 and D-10A.

 

[jakej]

Re: Dynon GPS Support- AVMAP EKP IV

From my expexperience there have been some NMEA datastream interface issues with the Avmap EKP IV mainly with autopilots including the most recent SoftwareUpdate 2.04.110R - 2007-09-26 - an autopilot will work on the ground but looses the Gps (NMEA) at speed.

Avmap assures me that another update will be done this week - we'll see hope this helps.

cheers, jake

 

[infobomb]

I have been in touch with AvMap and am helping them test a new version that should correct the missing magnetic variation problem in the $GPRMC sentence. I think a few more turns and they should have it working.

I am only testing the fix for mag-var since I don't have an auto-pilot (other than my wife).

-Neil

 

[Hal]

Hi Neil,
I guess this is the problem I am having with my D180-EKPIV installation. The wind vector is just not reliable. Please let us know the outcome of your testing. Now if Avmap would finish that XM weather they have been promising...
Hal
Sonex N808SX
Cornelius, NC

I have been in touch with AvMap and am helping them test a new version that should correct the missing magnetic variation problem in the $GPRMC sentence.  I think a few more turns and they should have it working.  

I am only testing the fix for mag-var since I don't have an auto-pilot (other than my wife).

-Neil

 

[infobomb]

Hi Hal,

Also make sure you put in Total Intensity, not the Horizontal Intensity, and Inclination instead of Declination. If either of these are entered wrong before you calibrate, your cardinal points will calibrate ok but headings get really off between them. This will also throw your air data (winds aloft) off.

Not that we made any of these mistakes...

-Neil

 

[Etienne]

Any chance of adding a baud of 115200?

The reason I ask is because the output from the efis is at 115200, and most com ports cannot receive and send at different rates. I'm building a computer-based system that needs to read in from the efis, and I'd like to feed GPS and SL30 data back to the EFIS, and would like to do that through the same com port.

 

[dynonsupport]

At the current time, it's unlikely we can add 115200 to the GPS support. In an embedded environment, feature additions like this aren't simple code changes. We have to drop down into assembly code to add support like that. If more people request this, we may reevaluate.

 

[DougN]

For those who are having difficulties with AvMap EKP-IVs, I'm afraid I've joined the club. Even when the GPS has a fix at takeoff, it often loses itself while flying. I took a video of the GPS flipping back and forth between a stated track of 270 and 90 - it couldn't figure out which way I was going (I was heading west). This I sent to AvMap asking for their thoughts on the matter.

My current conjecture is that the antenna placement in the airplane is critical. Any metal surrounding, or on top of, the antenna could attenuate or distort the signal. The antenna is mounted on top of the panel just under the foward canopy roll bar. There is also the possibility of EMI from the strobes and radios. I received a new antenna (it is an active component, and so could be the source of the problems), and went out flying today. Things seemed to be better for a while, then the "what direction are we going" issue rose its head again. It seemed to be corelated to where I placed the antenna; so I'm going to investigate that further.

What have others experienced with antenna placement?

I've also ungraded the SW to the 2.06.x version they've just published.

Taking the GPS out of the plane and using it in my car, it seems to work.

I've also experienced the "70 knot crosswind" but I've laid it off on the GPS at the moment. Frankly, my Dynon equipment has been rock-solid (version 4). I just love it.

There are unresolved issues with the DigiFlight II autopilot as well; but these seem also to be caused by the GPS issues.

Airplane: Zodiac CH601 XL
Avionics: DigiFlight II, EFIS D-100, EMS-D10, SL30, GTX-327, EKP-IV Pro, PS 1000 II

Any thoughts greatly appreciated; perhaps if we trade experiments and their results we can figure out what's going on.

 

[DougN]

Moved the GPS antenna from on top of the panel to under the canopy on the turtle deck behind the seats. This is away from the engine's electrical noise and all the local oscillators on the radios.

GPS Problems went away.

The winds aloft / cross-wind showing on the Dynon is now correct too.

For those who are having trouble with the EKP, try repositioning your antenna.

 

[Butt]

Hi,
i have tackled the avmap antenna issue by using an smb-bnc adaptor so as to use the garmin GA-56 antenna mounted externally on the fuselage for the best satellite coverage.

regards.

 

[dynonsupport]

Another customer called today having the same problem with his AvMap- the wind arrow was way off due to the ground track being "true" rather than "magnetic."

He then called AvMap and they sent him a link to a new download for his GPS unit, which he says fixes the problem. I don't have the info on the link or whom he talked to, but there does appear to be a new AvMap update that fixes this issue.

 

[DougN]

Thanks for the feedback. The ultimate cause for my problem, and I'm guessing many others, is the marginal design of the antenna used by the AvMap EKP-IV, and the unshielded cable carrying the signal (uses a 5v source on the center conductor, and the modulated signal carrying the GPS result from the active GPS receiver on the outer conductor). Attenuation of the signal due to noise and induced currents resulted in corrupted data; and everything seemed to go south from there. Other antennas seem to be more robust; but a simple change of antenna location may be sufficient to fix the issue. I'm told that this "never" happens with the Garmin GPSs; and that may be true, but the large viewable aea of the EKP-IV makes it seem worthwhile to figure out how to render the device usable.

There was also a continuing probelm even after upgrading the software until the location was changed; so, taking Dynon's point of view, ensure that your customers both upgrade the SW, and play with the antenna location when the problem is an AvMap EKP-IV.

All the best,
Doug N.

 

[n693w]

Neil

I'm presently running the EKP-IV in my RV7A with the TruTrak autopilot and the D100 EFIS am somewhat confused of how to wire the Mark IV to the D100. Can you or anyone out there give me some pointers?

Thanks for any help

Ron B

 

[dynonsupport]

Split the wire that comes from the AvMap and goes to your TruTrak. Run this wire to pin 22 on the EFIS (which is pin 3 on the PC update port).

That's it. It's really that easy. The D100 will auto-detect the signal and show it to you on the HSI. You can also turn on things like winds aloft if you have an OAT.

 

[DougN]

The way it was done in my airplane is just what is suggested in the Dynon installation instructions: serial GPS to the Dynon serial in. There are additional details depending whether you have more than one Dynon element, and whether you own a Garmin SL30. The install instructions suggest the Dynon elements tied together with the DSAB, and the GPS going to the EMS with the SL30 going to the EMS.

For the TruTrak, split the GPS signal and pipe it to both the dynon receiver and the TruTrak.

Pay attention to the baud rates selected. The EKP-IV only has 4800 baud. Ensure you set the TRuTrak to 4800 baud (hold the "mode" button until it goes into the setup mode, then "next" until you find the place to set the baud rate).

The Dynon auto-recognizes the baud rate, so nothing to do there.

On the EKP-IV, hit menu twice to get to the main menu, then choose "communications." Set NMEA to "on"; then choose RMC, RMB, and APB msgs (you can choose either APB or another I can't remember off-hand).

Take my instructions with a grain of salt; while I think they are close, I'd strongly suggest you read the install manuals for all the devices and plan accordingly.

Best of luck.

 

[n693w]

Thanks gents for the help on the EKP-IV - Dynon D100 hookup. I'll give it a try soon.

Again thanks

Ron B

 

[rngaines]

The new AvMap software works well. It was posted on AvMap page within the last two weeks. The communications set up page should be set to "processed". That makes the direction info going to the Dynon in magnetic.

I get the appropriate presentation on winds aloft/direction/speed. The Dynon HSI page works well.

 

[DougN]

Are you sure it should be set to "processed"? That is a fix for a particular autopilot (navaid I believe) which was having problems. The folks in the AvMap US office (specifically Dan Lyons) didn't mention this as a parameter to use for other than that set of issues.

Having said that, I haven't looked at the differences in output from the AvMap when either is selected, so I don't know what they are (could be something subtle). I too have upgraded and am getting correct winds aloft info; and I don't it set on "processed".

 

[DougN]

I just popped a note off to Dan Lyons from AvMap; and I'll post his response when I get it.

 

[DougN]

As promised:
--------------------------
Hello Mr. Norman

The Processed signal was created specifically for the TRIO auto pilot systems. With this system there was a "hiccup" that was causing the AP to lose GPS signal frequently. The NMEA output on the old generation of software (V1.11.50R and prior) was processed before being transmitted to external equipment. Think of it as a CD player in a car: There is a slight delay so that if you hit a bump and the CD skips, the player can have time to correct the data before it is sent to the speakers. The new generation of SW (V2.xx.xxxR) sends the signal directly in an attempt to speed up the transfer. Please note that there were never any complaints about signal interruption on Dynon systems with the new SW, and therefore either setting should function properly. The only complaint we had with the original batch of generation 2 software was that it was not transmitting a magnetic heading when set to do so. Software updates have corrected this problem, and we have had no new complaints.

If helpful I could answer some questions directly from this forum, I would just need to know where to find it.....

Otherwise please feel free to contact me with any questions and I will do my best to help.

Thanks,

Dan.
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