Garmin GPS AT575 with Pilotaware

[Admin]

Not sure about this particular gps receiver
But the one we use on Rosetta fx, produces an NMEA message
This is a $GPTXT message with text ANTSTATUS

To answer your question you need to plug into a PC or LINUX machine and connect a terminal (minicom or putty) and look for the above message when adding/ -removing external antenna

[peteD]

Ok thanks, I’ll have ago!

[peteD]

Could not see $GPTXT ANTSTATUS except on startup when ANTSTATUS=OK*25 with Putty,(at the limit of my knowledge here!)

So I used U-Blox u-centre which gave me a nice signal strength indicator display and responded positively to the connection of an active antenna,:-) , just need to try it on the AT575

[peteD]

UPDATE
Works very well, signal strength 50-60db on AT575, compared to pilotaware internal gps mouse 30-40 db.

So if you happen to have a redundant gps antenna (ex garmin430 etc) on your airframe and wish to use it instead of an internal gps mouse, the above mentioned dongle works well!

Thanks for all the input that enabled me to reach my goal :-)

[peteD]

Further Update-improvement
This dongle worked with my redundant Garmin AT575
https://www.amazon.co.uk/Geekstory-Antenna-Supports-GLONASS-Compatible/dp/B07ZR8R17Q

But was slow to aquire with occasional drop outs.

I thought that it would work better with the required 5v than the 3v supplied by the dongle so tried a Bias T as recommended.

Nothing...I suspected that it wasn't switching to external ant. and guessed the switching was due to no current flow so wired up a resistor and choke across the dongle antenna.

Bingo...rapid aquisition :-) :-)