Hi everyone,

Does anybody know of any Garmin units of present production (i.e. new units) that will accept an external antenna so they actually have an input for one?

My units with inbuilt antennas play up shocking with not getting satellites and only displaying half the info or completely wrong info if there is any info at all.

I have ordered a re-radiating antenna to see if this helps and in theory it should but until it arrives I will not know. (about 3 or 4 weeks - ebay from China). Worth trying for $20.

If that fails I see no alternative to a unit that will accept an external antenna or a hacking tutorial on adding your own external antenna even if it is hard wired straight to the motherboard!

Or a hacking tutorial on throwing out the useless GPS chip in the units and replacing it with something that actually works!

Anyone know of anything like this? I did find one on egadget but the pictures are long gone and not much good without the pictures.

Thank you for any help, much appreciated.

You don't say what type of unit, Automotive ,Hiking ,Marine etc. or mounting location
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Most "New" Automotive devices have an internal high sensitivity GPS antenna built into them ,with screen mounting I've not had any issues with a satellite fix
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Most older devices had MCX connectors to add an external antenna
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There are no general issues across the board with Garmin like you are describing, most devices work very well in that regard.
Sounds like you either have a specific dodgy unit, or if the symptoms you describe are across multiple devices then something else is going on in your situation and most likely sub-optimum mounting / position. E.g. a vehicle with strong shielding and you may need to adapt the mounting.
GPSmap78sc has an external antenna port however mine has worked fine everywhere as is for years including in vehicle and I've never needed to use the port.
As above if you can give more detail it will help to give more specific advice.

Hi,

It's a Nuvi 51LM.

It is mounted to the windscreen with the standard Garmin mount.

The vehicle has a very steep, almost vertical screen so the unit is not seeing the sky very well, it see's roof.

It is especially poor in the very early morning, sometimes not getting any signal for the entire length of the trip to work (about 20 minutes).

It does seem better in the afternoon heading home. So I don't think it's all the units fault.

I never had this problem before with a Nuvi 50 until recently and thought the chip had died so bought the 51LM only to have the same problem.

Not sure if something with the satellites changed causing the early morning poor performance?

Thanks for your thoughts.

Yes the issue will be your extended roof coverage. The only reason it sometimes works better is at those time there will just happen to be more satellites orbiting lower down toward the horizon it can then "see" through the windows rather than being blocked above the roof.
There is nothing untoward happening with them, the satellite constellation is constantly changing. Have a play around here and you will get the idea: [Please Register or Login to download file] The reason this site exists is to help mappers and surveyors plan for the times of best geometry - including angles above the horizon - to do their work.
If you haven't already done it you could try getting the unit as far into a corner as makes practical sense so it can see as much as possible up to the front...and also to the side...provided it's not getting into the shadow of a metal A pillar if your corner is that square.
On the main screen if you press the GPS signal strength icon for 3 seconds you should get a live plot of visible satellites, their positions and signal strength that can help as you move it around to locate the best position.
Otherwise I've not yet encountered an external antenna on an automotive unit so unless someone else can point out an option you are probably on the right track looking at a repeater.

I have on numerous occasions experienced poor satellite reception with the Nuvi GPS.
This is frequently a problem with larger trucks, SUVs or recreational vehicles.
You don't want to have to the GPS place so that it gets a good satellite signal at the expense of not being able to
easily view the Nuvi screen. I have used an older Nuvi (800 series) which has MCX connector for an external antenna.
I used a Gilsson Model MCX External GPS Antenna.
Works great extremely fast signal acquisition.

Blown8 wrote:Hi,
It's a Nuvi 51LM.
It is mounted to the windscreen with the standard Garmin mount.
The vehicle has a very steep, almost vertical screen so the unit is not seeing the sky very well, it see's roof.
It is especially poor in the very early morning, sometimes not getting any signal for the entire length of the trip to work (about 20 minutes).
It does seem better in the afternoon heading home. So I don't think it's all the units fault.
I never had this problem before with a Nuvi 50 until recently and thought the chip had died so bought the 51LM only to have the same problem.
Not sure if something with the satellites changed causing the early morning poor performance?
Thanks for your thoughts.

Maybe a Drive 51 or DriveSmart 51 as the nuvi range has been discontinued for a number of years.
I've just simulated your vertical windscreen by placing a Drive 50 on the inside of the kitchen window ,no vertical view of the sky.(house not moving)
Took less than 4 minutes to get to the point to navigate ,If you are, for example driving out of a garage continuing to drive maybe it is battling to get a fix? Try what i did to see if you get a similar result .The manual says [Please Register or Login to download file]