GDL 90 protocol for ADSB on Skyview


Oct 17, 2008
Unless you fly under Class B airspace, over Class C or above 10,000 feet you may decide if you wish to comply with the ADSB out mandate for 2020 as a matter of personal choice. Due to the fact I live and fly under the Mode C veil of Class B airspace and much of my flight is under B, over C or above 10,000 feet I am forced to equip. I am going to use a UAT to do so as I wish to retain my current transponders which are not Mode S.

I have equipped my aircraft to do this. I receive ADSB IN though the industry standard GDL 90 protocol on an iPad. I would like to be able to display this information on my Skyview. I am confidant Dynon will resolve the issues it is experiencing with their 472 ADSB receiver but this is not a good solution for everyone. In my case, I choose to retain my Mode C transponder but even more importantly I do not wish to make another hole in the aircraft. Another consideration is the difficulty even mounting such an additional antenna in order to get recommended antenna separation given the small size of the aircraft.

I would like Dynon allow the reception and display of ADSB IN data on the Skyview over one of the serial ports. This data should come from any source over the industry standard GDL 90 protocol. Most EFIS systems allow this today to include the Advanced line now owned and supported by Dynon. My proposal is that instead of having to install the ADSB 470/472 receiver and the associated additional external antenna I could pay a one time license fee to unlock the capability. In this way Dynon continues to thrive as a business, we gain the ability to access ADSB information from more sources including those which simply work better in individual cases. The mapping software on the Skyview was originally sold in this manner.

I have discussed this with Tech Support at Dynon and have been told this could be done. I urge Dynon to consider this alternate path to provide a means to display information which is meant to enhance safety of flight on the Dynon EFIS system I consider to be the industry leader.


I love flying!
Mar 1, 2015
Completely agree.  I spent a bit of time over my Christmas vacation from work attempting to decode the Dynon-proprietary ADSB-470 protocol, in an attempt to create a raspberry pi converter to GDL90 format, so that my ipad running Foreflight could finally receive ADSB weather and traffic alongside my Skyview.  Dynon's format is really screwy and nearly impossible to decipher (probably by design, to lock in revenue, which seems to be massively backfiring at the moment).

I, too, strongly urge Dynon to allow (even for a fee, though notably their competitors do it for free) GDL90 reception via RS232 at a minimum.  Receiving over WiFi would be even better.

Considering the fact that the ADS-B 472 was announced almost a year ago in March 2017, it's still not working right, and for months now it hasn't even possible for new Skyview owners to purchase a single working ADSB-in solution anywhere, enabling GDL-90 reception seems to be the least Dynon could do.


I love flying!
Apr 30, 2018

I would like to install a Skyview system when my plane gets added to the AML and don't want to (actually, won't) pull the existing GDL90 system out just to replace it with a proprietary system that offers nothing more than I already have other than a lighter wallet. Garmin came out with the G3X and immediately stated it was incompatible with the Avidyne boxes and GDL90 protocol, so right there is your competitive advantage.