GPS Integrity Lost

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   I've been flying with my IFD540 about 12 hours now and it's performed well - better than I had hoped, actually, but with one exception: it's ability to lock on to the GPS satellites seems to be pretty fragile.
Comparing it to the Dynon Skyview WAAS GPS, I have found that the IFD will only acquire 8-9 satellites when the Dynon finds 15, and that the IFD easily loses them.  Operationally, this has resulted in LPV approaches being downgraded to something less during the procedure turn.

I have a RAMI AV-801 WAAS GPS antenna that was recommended by SteinAir (where I purchased the IFD) and I'm wondering if that might not be the best antenna for this unit.  It is mounted on the top of the aircraft several feet away from the other GPS antenna so not sure that location is an issue.   Is there a different antenna others are using, or have others had good success with this one?

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bradthepilot Members Profile Send Private Message Find Members Posts Add to Buddy List Groupie Joined: 07 Jan 2017 Location: St. Paul MN Status: Offline Points: 65	Post Options Post Reply Quote bradthepilot Report Post Thanks(0) Quote Reply Topic: GPS Integrity Lost Posted: 30 Jan 2017 at 9:55am
	I've been flying with my IFD540 about 12 hours now and it's performed well - better than I had hoped, actually, but with one exception: it's ability to lock on to the GPS satellites seems to be pretty fragile. Comparing it to the Dynon Skyview WAAS GPS, I have found that the IFD will only acquire 8-9 satellites when the Dynon finds 15, and that the IFD easily loses them. Operationally, this has resulted in LPV approaches being downgraded to something less during the procedure turn. I have a RAMI AV-801 WAAS GPS antenna that was recommended by SteinAir (where I purchased the IFD) and I'm wondering if that might not be the best antenna for this unit. It is mounted on the top of the aircraft several feet away from the other GPS antenna so not sure that location is an issue. Is there a different antenna others are using, or have others had good success with this one?
	Brad Benson RV-6A N164BL

AviSimpson Members Profile Send Private Message Find Members Posts Add to Buddy List Senior Member Joined: 31 Mar 2015 Location: Lincoln, MA Status: Offline Points: 765	Post Options Post Reply Quote AviSimpson Report Post Thanks(0) Quote Reply Posted: 30 Jan 2017 at 1:39pm
	Might be the antenna. Below is the list of ones that are in the installation manual. Additionally, where is the antenna mounted? Can you also confirm what software level is on the IFD?
	Simpson Bennett Avidyne Corporation Product Manager

bradthepilot Members Profile Send Private Message Find Members Posts Add to Buddy List Groupie Joined: 07 Jan 2017 Location: St. Paul MN Status: Offline Points: 65	Post Options Post Reply Quote bradthepilot Report Post Thanks(0) Quote Reply Posted: 30 Jan 2017 at 6:39pm
	Thanks for the response! The antenna is mounted on top of the fuselage, and the software version is 10.1.something. I will look more closely at it when I am at the hangar next but I received the unit this month so I'd expect it's relatively new. The antenna issue is interesting from the standpoint that it is one that Avidyne sent to my dealer along with the unit itself; they are following up to see why Avidyne would have shipped an antenna that isn't on the officially supported list.
	Brad Benson RV-6A N164BL