Garmin 66i GPS Receiver capability compared to an iPhone XS

Former Member over 5 years ago

Hello,

Just curious if anyone has side by side comparison of the GPS receiver capability between the Garmin 66i and a Apple iPhone XS Plus (or similar iphone). When I was in Colorado hunting and and hiking in Glacier National Park with my iPhone 6s Plus and most recently in Great Smoky Mountains with my iPhone XS, my GPS receiver was able to always get a signal. Trying to determine the need for a GPS type device if the iPhone GPS receivers have been pretty good in my last few outings. Have others experienced that they were not able to pick up a GPS signal on a standard iPhone when their Garmin 66i was able to? I understand there are a lot of other benefits of a stand along device, but my question is only looking to understand GPS signal comparison.

Topic: Garmin 66i GPS Receiver capability compared to an iPhone XS

0 twolpert over 5 years ago

I don't have any data on this. There are a couple of obvious things.

First, the iPhone does assisted GPS. For back country use (outside the range of the cell network), this probably only affects acquisition time. It's likely to be longer for an iPhone than it is for a handheld.

Second, for some unknown reason, the 66i does not support all the satellite systems supported by other models in the GPSMAP 66 series. For example, according the the manual, the 66st supports GPS (US), GLONASS (Russian), and Galileo (Eurpoean) systems. According to its manual, the 66i supports only GPS. However, my 66i says GPS and Galileo. Apple marketing literature says the iPhone Xs (and older phones at least back to iPhone 8) supports GPS, GLONASS, Galileo and the Japanese QZSS system. Using GPS plus one of the others (which is how the Garmin receivers work) will get you slightly better accuracy than GPS alone. (Possible exception might be QZSS, with which I am unfamiliar. That does not appear to offer global coverage - useful only in the Asia-Pacific region?) iOS does not appear to offer explicit control over which system(s) are used. All you can do is turn location services on and off.

Third, the 66i uses a quad helix GPS antenna. The iPhones use a patch antenna. I would expect this to provide slightly better sensitivity, particularly in challenging conditions. OTOH, a lot of handheld receivers, including many from Garmin, use patch antennas quite successfully. This part gets too technical for me because it really depends on the effective aperture. Rule of thumb is bigger devices are likely to have better antenna performance.

I was unable to find any specifics on which GPS chips are actually used by the various devices. This is likely to make a big difference in sensitivity, but there is no way to judge without specific chip information.

I know you don't want to hear about other features. But the point of the 66i is the "i" for inReach. You get bidirectional satellite messaging and SOS capability even when out of range of the cell network. If you never travel outside that range, I'm not sure why you'd be interested in the 66i specifically?