GPS Antenna

[Rolo]

I have a TripNav TN-204 GPS antenna that I would like to inconspicuously affix, preferably away from the dash, while still getting good reception.

Pic and dimensions here: http://www.gpscentral.ca/products/rayming/tn204.htm

Has anyone mounted/affixed a GPS antenna rather than slinging it onto the dash?

[2 TONE PT]

Blue Meanie put the Mopar GPS in his this summer. I think he was talking about putting the antenna under the dash.

What did you do Dan?

[Rolo]

That would be perfect, but you need Line-of-Sight, no?

Originally Posted by 2 TONE PT

Blue Meanie put the Mopar GPS in his this summer. I think he was talking about putting the antenna under the dash.

What did you do Dan?

[2 TONE PT]

I may be wrong but I can't imagine that addition of a plastic dash cover would hamper the signal much when you consider that it would likely have to travel through the windshield, the roof at times and buildings depending where the satelite your currently picking up from is in relation to your vehicle position.

I should maybe clarify "under the dash". I meant under the top dash panel (remove dash top, install antenna and reinstall dash top) rather than buried somewhere in the lower part of the dash where it would definitely be shielded more by the firewall, the dash components and the rest of the body.

[Rolo]

Oh! ya, ok! That is a cool idea--invisible and close enough to not have to extend the cable.

I was thinking of putting it on top of the VIN and feeding the cable through the VIN label hole, but it would be visible. Ya, slipping it under there may work.

I was also thinking inside the windshield defroster vent, but heat may be a problem.

Originally Posted by 2 TONE PT

I may be wrong but I can't imagine that addition of a plastic dash cover would hamper the signal much when you consider that it would likely have to travel through the windshield, the roof at times and buildings depending where the satelite your currently picking up from is in relation to your vehicle position.

I should maybe clarify "under the dash". I meant under the top dash panel (remove dash top, install antenna and reinstall dash top) rather than buried somewhere in the lower part of the dash where it would definitely be shielded more by the firewall, the dash components and the rest of the body.

[Bugdude21]

Actually the GPS antenna HAS to have a view of the sky.

Things like buildings and trees will block the signal to and from the satellites. This is why most new systems come with a gyroscope, so your system has a way to track your movements when not in contact with the satellites (ie. left turn, right turn, etc etc)

I can block the signal by covering it with my hand....so I would imagine that the dash deck would block it fairly effectively.

There are two options for the antenna really: the dash or the roof.

This would be why everyone's Sirius radio antennas are mounted on the roof......

Sorry.....

John

[Rolo]

That is how I understood it.

I wonder if the rear window or the side windows toward the rear would provide a high enough azimuth to view GPS satellites. I will have to tinker in the driveway to get a feel.

Nice PT you have there, BTW.

Originally Posted by Bugdude21

Actually the GPS antenna HAS to have a view of the sky.

Things like buildings and trees will block the signal to and from the satellites. This is why most new systems come with a gyroscope, so your system has a way to track your movements when not in contact with the satellites (ie. left turn, right turn, etc etc)

I can block the signal by covering it with my hand....so I would imagine that the dash deck would block it fairly effectively.

There are two options for the antenna really: the dash or the roof.

This would be why everyone's Sirius radio antennas are mounted on the roof......

Sorry.....

John

[Bugdude21]

Since the GPS needs at least three satellites to triangulate your position you might be able to get away with mounting the antenna low on the rear window. You wouldnt be able to pick up the satellites at the front of the PT but the sides and rear would be covered. Most systems have a choice of up to 9 satellites to get a signal from (my Alpine set up even shows me where the satellites are and how many I am gettings readings from at any given moment)

You may even try painting the darn thing whatever color you need to get it to blend in.....don't now how that would affect the signal tho. I am not a huge fan of how the antenna looks on my dash, but the thing's gotta work.......

Thanks for the compliment on my PT......going in for paint this winter so it'll look different by next show season......

John

[BlueMeanie]

Originally Posted by 2 TONE PT

Blue Meanie put the Mopar GPS in his this summer. I think he was talking about putting the antenna under the dash.

What did you do Dan?

Well YES!!! I placed my GPS antenna under the dash pannel between the gauges and the air vent about 2 inches from the windsheild. The plastic pannel on the dash does not effect GPS's freq. (which I cannot remember right now.) A parking garage or a tunel are comletely different stories. I typically have 6 or 7 satellites communicating with my NAV system.

Bugdude21. You are partially right. Most GPS units have a gyroscope to aid in the location of the car. There are 3 real methods that are used for vehicle location. The main one is GPS. Then you have a combination of direction and distance (5 paces north, 2 paces west). The final method is called dead reckoning. Dead reckoning works by comparing the first two methods to the map and put you in the nearest road, if necessary. Basically, the nav system will realise that you are driving down the highway, not across a corn field.

About 11 years ago, my father was a member of a team of engineers that developed some of the very early GPS systems. The test system that was installed in my father's car had an antenna that was about 6 inches in diameter and 2 inches tall. The antenna was magnetic and sat on the trunk. People used to scream at us at intersections to inform us that we left the gas cap on the trunk.

Professor Dan

[Rolo]

Originally Posted by BlueMeanie

Well YES!!! I placed my GPS antenna under the dash pannel between the gauges and the air vent about 2 inches from the windsheild.

Thanks for the input...that is what I was looking for. How did you route your cable?

I plan on tucking the GPS mini-DIN connector behind the center dash storage area (above the lighter/outlet), completely concealing it when not in use. When I have my PocketPC mounted, I can just pull the connector out and plug it into the PC/outlet cable.

I want to have as much info as possible before I take my car apart, heh.