NUVI vs 64s

[+Thot]

I have a NUVI and a 64s.  The NUVI works in the car but the 64s doesn't.  For the 64s to point to a cache the car has to be moving or I have to be outside.  Why is this?

[RuideAlmeida]

6 minutes ago, Thot said:

I have a NUVI and a 64s.  The NUVI works in the car but the 64s doesn't.  For the 64s to point to a cache the car has to be moving or I have to be outside.  Why is this?

 

While the Nuvi uses the vehicle as antenna, the 64s dont have a clear line to the satellites... unless you (or preferably a passenger) stick a arm outside the windows, by instance.

Edited February 28, 2020 by RuideAlmeida

[+Mineral2]

The metal and electronics of the car confuse the compass. You'll notice that the nuvi doesn't actually have a compass and only points in the right direction when the car is in motion. It just happens to hold the last direction when you stop.

[+Atlas Cached]

Google 'Faraday Cage'

[+JohnCNA]

1 hour ago, Thot said:

I have a NUVI and a 64s.  The NUVI works in the car but the 64s doesn't.  For the 64s to point to a cache the car has to be moving or I have to be outside.  Why is this?

The Nuvi does not have a magnetic compass. It determines your direction from the movement of your car.  The 64S has a magnetic compass which gets totally confused because it's inside a metal cage (your car).  When you start moving, the magnetic compass gets shut off automatically and the 64S will operate the same as your Nuvi.  However, when you stop at the next traffic light, the 64S will turn the magnetic compass on again and the arrow will jump to the wrong direction again.  You can turn off the magnetic compass in the 64S which will stop this behavior.  But then you'd want to turn it back on again once you get to your destination and get out of the car.  Or you could do what I did when using the 64S to navigate while in the car.  Just live with it and ignore the jumping arrow when you're inside the car and stopped.

 

By the way, this is not unique to the 64S.  Any handheld with a magnetic compass will have this same issue.

[+Thot]

I'm not sure I understand.  When as passenger-navigator I hold the NUVI too far from the windshield it will loose satellite reception and I must move it forward to regain them.  So I think it's seeing the satellites through the window not using the car body.  I think Mineral2 is correct.  Neither understand which direction to go when sitting still inside the car and I had just never thought about/realized that and figured the NUVI always knew which way to go. 

Edited February 29, 2020 by Thot

[+ecanderson]

@Thot

You now understand the answer to the original question, but there's a second issue that you've brought up -- that your Nuvi loses satellite reception if not close to the glass.  Personal experience with both even older Garmin and newer TomTom devices in my own vehicles says I can place these units on top of the cubby in front of the floor shifter and they'll still work just fine.  Any automotive GPS I've used in the last 15 years has been fine with any position inside the car (constellation at lower elevation keeps them happy enough).  I even have surprisingly good luck inside open sided parking garages.  That brings me to ask about your specific vehicle. 

 

Metal oxide windshields act as major league attenuators of RF signals at satellite frequencies (and many others).  I'm wondering if you've got to keep it stuck right up there to get what little signal is left.  While these windshield glass materials helped with heat loading and UV on the dash, they were murder on RF.

 

Unless you're driving an exotic or a few other vehicles, these issues should have ceased on almost all vehicles newer than 2003.  Take a look at the attached PDF (the purpose was to explain problems reading toll tags, but the issue is the same) that covers a lot of possibilities to see if your vehicle is among those that might be suffering from this issue.  Well nuts -- can't attach a PDF.  Well, here it is, the hard way I'm afraid, to communicate something others may find problematic as well...

 

 

 

 

[+kunarion]

On 2/28/2020 at 8:56 PM, Thot said:

I'm not sure I understand.  When as passenger-navigator I hold the NUVI too far from the windshield it will loose satellite reception and I must move it forward to regain them.  So I think it's seeing the satellites through the window not using the car body.  I think Mineral2 is correct.  Neither understand which direction to go when sitting still inside the car and I had just never thought about/realized that and figured the NUVI always knew which way to go. 

 

The Nuvi (as mentioned) decides where "North" is (and therefore, the direction you're heading) by comparing the difference between GPS points as you drive.  Such a "GPS Compass" requires a certain speed, like over 5 mph.  And (also as mentioned) the Nuvi may not be getting great GPS signals, due to your car windows.

 

The 64s might be set to Magnetic Compass (usually that's the default, and you can select that setting), and still have trouble inside a car.  This is because the car is pretty much a big magnet.