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Garmin G5 Internal GPS Reversion

krw5927

Well Known Member
I have a G5 as a backup display to my other-brand primary EFIS. The G5 is fed GPS and nav data over RS232 coming from a GNS-480. I do not have any other external GPS antenna hooked directly to the G5.

When I turn off the GNS-480, the G5 displays a GPS failed message and red X's over some of the indications. I assume that if the GNS480 were ever to fail in flight, the same results would occur.

Given that the G5 has a GPS receiver and antenna built in, and I can select in setup mode whether to use that internal receiver or an RS232 GPS source, is there a way to set it to automatically fail over to the internal receiver when/if RS232 GPS is removed?

If this isn't currently available, I really think Garmin should consider adding that to the next software release. Having to enter setup mode in flight when you've already experienced another failure doesn't sound like fun.
 
If this option doesn't already exist, seems like Garmin has lots to catch up with other competitors.
 
By way of contrast, the GRT Mini has an internal GPS and can accept input from an external GPS.

Like Kurt, I have our Mini-X wired via RS232 to the GNS480. The GNS480 is configured as GPS1. The internal GPS is configured as GPS2

When the 480 goes off line a "GPS1 Lost" message appears on the screen. Acknowledge the message, select GPS2 as the nav source and you're back in business. Takes about 5 seconds.

NOTE: the GRT attitude solution is not reliant on airspeed or GPS data so no big red X appears should either pitot pressure or GPS be lost.
 
Hello Kurt,

Not to worry, the G5 is certainly designed to use its own internal GPS receiver in the event that data from another source is unavailable. You will want to verify that a) your G5's internal GPS receiver is enabled, and b) your G5's internal GPS antenna has a sufficiently good view of the sky, or else the optional external GPS antenna is connected. Please feel free to contact us using the information below if you need further assistance with your G5 installation.

- Matt
 
My G5 install required external antenna to RX GPS

My G5 installation is just under the glare shield and would not receive GPS without using an external antenna. Once I installed the external antenna it worked reliably. Now my 796, on the other hand, works fine mounted just below my glare shield with or without an external antenna.
 
Hello Kurt,

Not to worry, the G5 is certainly designed to use its own internal GPS receiver in the event that data from another source is unavailable. You will want to verify that a) your G5's internal GPS receiver is enabled, and b) your G5's internal GPS antenna has a sufficiently good view of the sky, or else the optional external GPS antenna is connected. Please feel free to contact us using the information below if you need further assistance with your G5 installation.

- Matt

This is good news, Matt, thanks! I'll go do some more testing and report back. My G5's internal antenna may be getting masked by the glare shield as Mark mentioned.
 
Just to close the loop - I added an external GPS antenna and now my G5 behaves exactly as Matt said it would. It was dropping out because the unit's internal antenna was, at times, masked by the glareshield.
 
Just to close the loop - I added an external GPS antenna and now my G5 behaves exactly as Matt said it would. It was dropping out because the unit's internal antenna was, at times, masked by the glareshield.

Kurt,
What kind of external antenna did you use for your G5?
 
Kurt,
What kind of external antenna did you use for your G5?

The G5 installation manual says a Garmin GA 26C antenna is compatible. Well, I had a Garmin GA 27C external antenna on the shelf from back when I flew with a 96c handheld GPS. Reading the specs, the antennas are similar, just the wrong connector on the 27C. So I purchased a MCX to BNC adapter and hooked it up just as a test and it worked great. Much stronger lock on way more satellites than just the internal antenna masked by the glareshield.
 
Does anyone know if we can use a splitter to share the signal from the G3X GPS antenna?

In theory yes, but splitters for active (DC powered) GPS antennas are usually far more expensive than a cheap antenna for your G5. You can mount the G5 antenna to the glareshield or even under the top cowl as many have done here.
 
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