GPS Glareshield Antenna for GI-275

[Rob58]

The Garmin GI-275 base model is really packed full of a lot of features, including a VFR GPS. It seems like a lot of functionality for the price and can be installed with an A&P sign-off. I’m trying to understand the options – and differences – found in the many small portable GPS antennas available. Are there frequency or power compatibility factors that need to be considered? Or can one of my external GPS antennas be shared between the GI-275 and the IFR navigator? Feedback to help educate me is much appreciated!

 

[Rob58]

I'm going to simplify my question in hopes that one of the avionics experts out there might be able to give me an answer. Here goes... does the GI-275 base model provide power through the BNC connector for compatibility with an active GPS antenna?

 

[Kevin Holbrook]

As the GI-275 is a certified / TSOd device, Garmin's installation instructions would apply, unless you are installing into an experimental. Garmin certainly calls for their own antenna to be used (even their Aera series of portables call out the external antenna to be used).

So while one of the many external GPS antennas may work, Garmin's installation requirements almost certainly won't allow it.

GPS antenna splitters aren't really a thing

 

[Der Fliegermeister]

I wouldn't advise splitting your existing GPS antenna with the 275. Just supply the serial information from your existing GPS to the 275. That's how Garmin will have your installer do it.

It's a great unit and I don't think you'll be disappointed with your purchase. Just make sure a reputable shop does the install. It's not worth finding an A&P that MIGHT know what he's doing to install it to save a few hundred bucks if you end up having to take it to a real avionics shop to work out the kinks.

Keep us posted

 

[Rob58]

As the GI-275 is a certified / TSOd device, Garmin's installation instructions would apply, unless you are installing into an experimental. Garmin certainly calls for their own antenna to be used (even their Aera series of portables call out the external antenna to be used).

So while one of the many external GPS antennas may work, Garmin's installation requirements almost certainly won't allow it.

GPS antenna splitters aren't really a thing

Really appreciate a couple of replies to my post. As you suggest, I will go with the Garmin 010-12444-10 and spend the $189 for an antenna that is really worth about $20. I understand the rules here and I will follow them. Part of the reason for posting my message was to learn about the technology behind a GPS antenna, but admittedly I have more important things to spend my time on.

As for Bandit's message... yes once I have a GPS navigator installed (I have none at present) the signal will be sent as you mention. That's happening several months from now. However the base model of the GI-275 has the built-in VFR GPS, which is a very nice feature. The GPS built into the GI-275 actually provides a lot of functionality and is a useful backup. I'm excited to have this feature working and at this point all I need is the glareshield antenna.

 

[Der Fliegermeister]

@Rob58
I apologize. I must've misread your prior post and assumed you did have a GPS navigator.

Sounds like you've got things figured out! Enjoy that shiny 275