External Antenna

Here's a list of all current and discontinued Garmin products that accept an external GPS antenna: https://buy.garmin.com/shop/shop.do?pID=1326

None of the current Nuvis take an antenna. You would have to buy an older one on that list.

class3

I think the reason there are no late models with external antenna jack is the new gps units are highly sensitive. Therefore the need for an external antenna does not exist

But it's more likely the external antennas were a low demand item so the company could reduce its cost by eliminating the hardware needed to support it.

That certainly sucks. No, I have an older unit already. The 760. I guess I'll have to use that when I need the antenna.

Class C motor home with a large overhang. I see my GPS many times reporting the wrong speeds and showing a very low signal strength. Especially in areas with large trees or in canyons, etc.

That overhang reduces the vertical horizon from 90 degrees to about 50 or 60 degrees. And the forward look to way less than 180 degrees. Using the antennal on top with the 760 I always saw rock solid signal strengths no matter where I was.

I have an antennae which is usable on the 855.
My 3790 though can receive a signal in a room about 6 feet away from a north facing window.

So maybe as mentioned before the newer units are far more sensitive.

Yes, newer GPS units are more sensitive -- the RF front ends are about as good as they can be.

The other issue is a different kind of sensitivity -- CE labeling (for the EU) requires the device pass strict electromagnetic susceptibility tests against a set of shocks and discharges (see for example IEC/EN 61000-4-2 - these tests can be fun to do).

One way to make these tests easier to pass is to eliminate interfaces to the outside world -- particularly those which by their nature must be extremely sensitive and handle very low level signals, such as for an external GPS antenna.

It only costs a few cents to provide protection, but in the consumer market, it's about the margins, man... Reduce costs and try to keep those margins up.