BAC5point2

Hey guys,

I am about to install a Kenwood DNX7100 and I just got my antenna in the mail. It's a Garmin GXM30 "smart" antenna. It's required so that I can receive XM radio/Nav-traffic/Weather/Stock updates in addition to being my nav antenna.

I opened the box and noticed that this thing is HUGE. It's like a hockey puck! Seriously, about 3" in diameter and about 1" thick!

So, I'm contemplating mounting locations.

I drive a 1998 Subaru Forester. It's got a roof-rack (Yakima Loadwarrior with extension) with my spare tire mounted up top and two bike trays. My current XM antenna is located front-and-center on the roof right above the rearview mirror (a standard Delphi antenna, the tiny one). The size of the GXM30 and the shape of the roof at that location (slightly curved) won't allow me to place the new antenna there. Plus, even if I could, I wouldn't. The GXM30 is really ugly.

But, since it's so large and awkwardly shaped, I was hoping I could do something else with it.

Does anyone have any experience dash-mounting this particular antenna?

I know they say you need a "line-of-sight" to the sky, but exactly how literal should I take that?

I have seen some of the worklogs and projects of some of the BMW guys here using CarPC's and mount GPS and XM antennas inside the third-brake-light housing on the rear decklid. I haven't heard complaints, but I haven't really researched it too in-depth.

Here's my thought. On the dash, I have a compass/temperature/barometer readout. It's in a nice little plastic pod and it fits well. I haven't taken it apart recently, but I THINK there is enough room for me to mount the antenna between the pod and the compass unit. Would I significantly reduce the effectiveness of the GPS antenna by mounting it under a 1/8" sheet of plastic and having it on the dash?

My other idea is to pull down the overhead map-light pocket and stick the antenna to the underside of the roof skin beneath the headliner. It would be totally hidden here as well, but would that thin sheet of metal be enough to severely hinder the performance of the antenna (and thus my GPS and sattelite radio)? I don't know how hot it would get in that part of the car either.

Does anyone have any experience with any of this?

Sorry for the long-winded post!

Phil

BAC5point2

41 views and no one has any input?

JimmyFitz

You can't expect your problems to be solved overnight. Anyway, the plastic won't interfere with your GPS reception, but some windshields have metalic particles embeded for tinting and that can. Best for you to just put the receiver on top of your dash and test it first to see if the reception is good compared to when not looking through the windshield. If it is ok there, put it inside the pod as you suggested and see if it is still acceptable. Seach for "GPS mount" if you want other ideas.

__________________
2002 T-Bird, Via SP13000, Travla C158, M1-ATX, 1GB RAM, 120GB 2.5" drive, SlimSlot DVD-RW, XP, RR, Winamp, Xenarc 700TSV, HTC Touch PPC/Phone, BU-353 GPS/iG3, Elmscan OBDII, Griffin PowerMate, 2 Blaupunkt amps, Polk spkrs, 5 sec startup/STR
~Jimmy

BAC5point2

What about the metal of the roof skin? Would magnetically mounting the antenna to the underside of the roof skin hinder reception?

JimmyFitz

Yes, metal will significantly reduce the signal.

__________________
2002 T-Bird, Via SP13000, Travla C158, M1-ATX, 1GB RAM, 120GB 2.5" drive, SlimSlot DVD-RW, XP, RR, Winamp, Xenarc 700TSV, HTC Touch PPC/Phone, BU-353 GPS/iG3, Elmscan OBDII, Griffin PowerMate, 2 Blaupunkt amps, Polk spkrs, 5 sec startup/STR
~Jimmy