Boozehound

I'm no electronics wizard like some of you on here, but now that I'm getting less than the best gps signal reception with my tint, I've been kicking around a few things:

- Why is it that it's assumed the GPS antenna would interfere with the TPMS? Doesn't the GPS just recieve (no transmission to interfere with)?

- What other advantages does placing the antenna on the rear deck have (does shorter wire length make a huge difference)?

- If relocating the factory antenna isn't an option, is there any difference between GPS antennas (thinking replacement of factory antenna with something better at receiving, or something external)?

- Is there a quantitative difference between the antennas for satellite radio and GPS? Is there a big frequency difference between the two broadcasts?


I'm not chomping at the bit to start on any of the antenna projects (the dead reckoning is pretty darn good), but I thought I'd marinate on some of these ideas... Any illumination you guys can provide would be helpful.

jtdwab

Can you explain better what you Nav is doing? When you say low signal strength what do you mean?

I don't have any tint but I have heard that the metallic tints tend to block the signal to the antenna which is what I guess is your problem. If you moved it the front dash which I am guessin you didn't tint the receptoin should return to normal.

Of the antenna's I have seen before they use a round cable similiar to coax (but much smaller) from the antenna to the processor. The cable is shielded to adding length should not be a problem within reason. I would not run the cable all the way around the car to get it their the straighter the shot he better. The hard part maybe getting the original out. I haven't hunted mine but I thought they were up a the top of the roof under the dark section of the glass.

I guess another thought is that if the original is up at the top of the rear window in the region that is already dark then maybe you can open the tint over that one spot to get the receptoin back. I'm just guessing with this though.

mazradiodoc

In addition to previous post, there is a differance in sat. antenna and nav. antenna. You should be able to buy an aftermarket antenna with the same connector as the nav player. I think the antenna is located at the bottom of the rear window but I maybe wrong.

Boozehound

To explain a little more first... I had my car tinted with ceramic Huper Optik 30 ten days ago, and immediately after tinting, the GPS icon will drop out on the screen when there should be no reason it's not getting a good signal. Upon going into the backdoor menu (3-3-2), it looks like most of the time it only hangs on to 3-4 satellites at best (you get the icon at 4 I believe), but I've seen it as high as 6-7 with the tint. It's a noticible departure from the previous reception, which was pretty stellar.

The antenna is located in the middle of the center section of the package tray under the plastic cladding. It appears to be a brass piece that has two "ears" that fit into holes drilled in the metal package tray, and there's one bolt holding it in place. It's a little hard to explain, but there's a pretty good diagram in the shop manual (check it out here https://www.rx8club.com/showthread.p...threadid=31992 - it's under 'body-interior-GPS navigation')

I guess the next thing I'll do before too long is take apart the back seat area and see how things are plugged in/attached, but I have a bad feeling it's a proprietary connector that's used to connect the GPS antenna. As for the difference in GPS antenna and satellite antennas, the car only has one (for the nav), well, at least that was the case until I bought an XM Roady2 yesterday. Interestingly enough, it's antenna sees through the HO tint just fine. Weird.

Sputnik

Metallic tint will affect reception, ceramic tint should not. I wonder if they installed cheaper metallic tint instead of the ceramic.

As for your original questions:

-I don't remember hearing anyone say that it interferes, but some radio receivers (like AM/FM radios, radar detectors) are super-heterodyne. Without going into it, that means that they do transmit a weak signal that might interfere with other things. For example, several AM/FM radios tuned to the same station have shown to interfere with some airplane radio equipment.

-The rear parcel shelf is also farther away from RF interference from other dash equipment. Whether that RF interference will affect the GPS reception, I don't know.

-Like Mazdaradiodoc sez, GPS antennaes are pretty interchangable with each other.

-Like Mazdaradiodoc sez, GPS antennaes are different from sat radio antennaes.

---jps

Boozehound

I would guess that they did install the ceramic - it at least has the characteristics described by HO (high clarity & IR rejection for the level of darkness). It's possible they pulled the old switcharoo on me, but I don't know if there's a good way to check.

After spending some time on www.tintdude.com in the forums (typically frequented by tint installers), basically the jury is out on the HO stuff - there are other people that have reported having interference with the ceramic 30 tint like I have, and then again, there are those who swear it won't affect it at all. Another thing to consider - just because it says ceramic, doesn't mean a damn thing. A ceramic by definition can be made of metallic compounds, and you can twist that definition into whatever suits your business model if that's your aim.

So I guess the consensus is that another antenna should operate with this unit so long as it can be connected. That sounds good to me - and I suppose it makes sense - every gps out there should be receiving from the same set of satellites up there...

Maybe after work I'll have a gander at the factory antenna (who knows, maybe even take some pics).