XM Radio Antenna Placement [Archive] - Cadillac XLR Forum: XLR and XLR-V Forums

: XM Radio Antenna Placement

10-24-2003, 03:46 PM
Since the XM Radio antenna topic was covered in a few different places, I am starting a new thread.

Attached* is page one of the two page instructions that came with my antenna. From my eye, it clearly puts the antenna close to the back of the trunk lid.

My dealer also got back to me with the answer from his source, restating the above.

*PDF is not a valid file to upload, so I'll put it at
http://www.icuonline.com/antenna1.pdf and

Hey Troy, how about letting PDFs upload!

10-24-2003, 04:48 PM
The initial response I've gotten is that your diagram is accurate. There was a late change that moved the antenna location and wasn't communicated to everyone. The diagram is the way the information is communicated to the dealerships. Sorry about the confusion!

My own guess is that this boils down to looks versus functionality. There is some degrading in signal strength if the antenna is inside the vehicle. On the other hand, there is the astetics issue for an antenna outside the vehicle. Since the antenna is *relatively* small, I guess the powers that be decided to go for signal strength over looks.

If I hear any more, I'll post an update. But right now it looks like the XM Radio antenna goes towards the back of the XLR's trunk, outside of any windows.

11-04-2003, 10:46 AM
Attached is a recent photo of a Neiman Marcus XLR with the XM Radio antenna installed, taken at David Taylor Cadillac (Houston). The photo is taken from the side and the rear of the XLR is to the right.

The XM Radio antenna is circled. Just to clarify, the circle was added to the photo and is not part of the XLR.

11-04-2003, 01:56 PM
It's hard to tell from the photo how much impact the antenna has on the lines of the car, especially with the circle. I'm still debating whether to install my antenna or not.

11-04-2003, 02:12 PM
Check the 1st and 3rd photos in this thread:

The antenna is visible in both of those images. The bottom line is a choice between a slight change in the lines versus having the antenna properly installed so XM Radio won't mute.

11-04-2003, 04:54 PM
I wasn't going to use this photo since it came out a little dark. However, it does show the XM Radio antenna against the XLR's center line. Hope this helps...

11-04-2003, 07:23 PM
I think the pictures have "talked" me out of installing the XM Radio antenna.

11-05-2003, 08:55 AM
Of course the other way to be absolutely sure is to take the XM Radio out of its baggie and put it on top of the trunk where it would be placed (drilling no holes, of course). This way you'll be absolutely sure of what it will look like.

11-05-2003, 06:53 PM
It won't lie flat as it has a piece that goes through to the inside of the trunk. I'll stick to my CDs.

11-07-2003, 08:15 AM
After seeing these photos its no antenna for me. Does anyone know if the antenna installation is done at the factory or a dealer installed feature. I'm still ordering Sat. radio but not going to have the antenna mounted. Hoping there will be an aftermarket offered later.:( :(

11-07-2003, 09:46 AM
Thought I had made a mistake but now glad that I didn't order!:iagree

11-07-2003, 09:58 AM
The ones I've seen are dealer installs. The PDF above also indicates that. Of course, that isn't anything official just what I've seen.

Your advisor may know more details.

11-07-2003, 01:44 PM
An aftermarket antenna that is less obtrusive would be a good idea but I'm not holding my breath. the XM Radio system may be proprietary.

11-17-2003, 10:08 AM
has anyone thought of trying some different location. I have mounted them in many Corvette inside the rear fascia and they have worked great. I am wondering if I can fid a space in one of the fenders. If anyone has done anymore work on this let me know.:thumbs

11-17-2003, 12:11 PM
That certainly can be done with enough work.

I see two issues, though -

1) The cabling goes to the trunk area, so you'll have to find the location the cabling comes to before the trunk and re-route from that location. The moving trunk/roof is going to make this more difficult.

2) I expect about a 6dB drop in apparent signal strength when mounted inside a surface. Depending upon the type of material that could be more or less. Also the closer you are to the equator, the higher the signal strength will be. So those in the South may have better luck than the people in the North.

Obviously if it is incorrectly done, you'll be more prone to drop-outs which on XM Radio result in muted (dead) audio for a few seconds. It is why I was kind-of glad that the antenna was moved outside, despite the appearance issues.

11-17-2003, 12:35 PM
good points. I was looking at the instructions that came with the antenna and noticing the wiring on the trunk lid. this may put a bit of a problem in the mix.

I have done a number of vets and maybe it is the material the bodies are made of and maybe it is because I am in FL., but, I have gotten excellent reception with no significant drops reported by any one. Anyways just shoting around ideas.

11-17-2003, 12:49 PM
There is a new antenna available called an "XM Micro Antenna". It is small-enough to fit inside a hand. It would not be painted the color of the XLR, but that is another option. I also have not had any experience with the difficulties of installing that antenna rather than the factory antenna (don't even know if it would work).

Anyway, you can check the XM Radio web site for more information on the Micro Antenna.


(look towards the right on that page)

11-19-2003, 10:51 AM
thanks for the pic of the micro ant. that just might work out especially since mine will be black.. :party

11-19-2003, 06:33 PM
It is not apparent how to purchase just the little antenna. ANyone have better luck with that?

11-19-2003, 07:45 PM
Here is one link I was able to find:


Once again, I have to note that I don't know if the antenna will work with the XLR's XM receiver. Someone will have to test that.

11-20-2003, 09:37 AM
thanks for the link. I think I might just order one so I'll have it when my car gets here. Question it says single connector wire, my sony has 2 wires will the factory radio be compatable. Inquiring minds want to know.

11-20-2003, 04:05 PM
My big concern is that one of the antennas is a powered antenna and the other isn't - or that one antenna is expecting a different DC voltage than the other. I really don't want anyone damaging their XM Radio module or an antenna. I don't have enough data to say whether or not this is a good idea.

So, I strongly urge someone who has time to check with the manufacturer and make sure that the Micro Antenna is really a good replacement for the GM-spec'ed antenna.

Just had to throw in a word of warning...

11-20-2003, 06:26 PM
After reading the information on the Web page posted above, I do not get the impression that this small antenna will work on the radio that comes with the XLR. Certainly the magnetic mount won't work on the composite, you would have to use the adhesive. But more inportantly, if you scroll down to the bottom of the page, it clearly states with satellite radios it will work on and also states at the very bottom that it wil not work on radios that have two wire antenna connectors. Correct me if I'm wrong.

11-20-2003, 06:37 PM
That's the way I read it, too. But, the manufacturer would be able to say for sure. What does the antenna lead look like (coax of some type?)?

12-03-2003, 09:24 AM
I had told my dealer not to install the sat. ant. that comes with the car so I could find a smaller after market one. I talked to my XLR personal assistant yesterday, he informed me that if u order sat. radio the trunk will be predrilled for the ant mount. Seems that if u want the radio u must have the antenna. I've canceled the radio option. WHY WOULD CADDY RUIN THE LINES OF THIS CAR...:(

12-03-2003, 10:50 AM
I didn't think the holes were pre-drilled. The assembly instructions (see above append) indicate that it is *not* pre-drilled.

However, the proof is in the pudding (or trunk, in this case). Have the owners who ordered satellite radio received their XLRs with the holes pre-drilled?

12-03-2003, 01:48 PM
My NM XLR came with the XM Radio but had no holes drilled.

12-17-2003, 12:25 PM
Mine has XM and there are no holes. I have not tackled the ant problem yet. I have been working on other changes. The car will soon have new wheels and tire and different exhaust tips. I can't stand the ones that come on it they like just like a deville. I will post pictures as I get things done. It will probably be next year by the time I get the wheels on but I will post some pics. As I finish my projects.

12-18-2003, 03:33 PM
I've been looking at the Terk antennas. Here is one that looks interesting...


Anyone have any experience with this antenna?

12-18-2003, 05:08 PM
The magnetic mount is useless. Also keep in mind that XM is pushing a portable unit that uses one wire to the antenna and the XM radio unit installed in our cars has two wires (I believe). The spec sheet in the URL above does not specify number of wires.

12-19-2003, 11:27 AM
I just got an update from TERK Technologies. In March they plan to release a smaller antenna called the XMicro. It will be about the size of an add-on GPS antenna.

In addition to the small size, it will have a splitter cable option to allow the antenna to work with GM units.

No spec sheet available, yet.

12-28-2003, 08:15 PM
Just picking my Silver XLR (Ill Plate EXLR8) up and after having XM in my STS since May I had to have it in the XLR---well to me at least with the ant. being painted the body color whatever u believe the trade off is, its well worth it! It seems like i want to drive the car all the time and having XM along for the ride makes it that much better of an experience. Also my main information contact Mr. XLR tells me it will be be quite a long time b4 something new comes along that will meet the XLR & XM QC specs.

02-26-2004, 08:07 PM
I know this has been shown but I thought I would give a few different angles of the XM antenna mounted in the correct location on the deck.

02-26-2004, 08:12 PM
Here is a second photo.

02-26-2004, 08:16 PM
Top up view with XM antenna

02-27-2004, 02:57 PM
Thanks for the pictures. I'm still convinced I don't want to install my antenna. I wish there was some other way...

02-27-2004, 03:32 PM
After having XM for 1.5 months, I couldn't go back to no-XM again. Most people who see the antenna think it is "cool". BTW, XM is adding local traffic and weather for the top markets starting March 1st.

02-27-2004, 08:18 PM
Traffic is the hole in the navigation system. If it showed real-time traffic on the maps using the TANN maps for instance, navigation systems would be so much more useful.

For those of you not familiar with TANN, go to http://traffic.tann.net, find your area then bookmark the page for future reference. It's not available in every area, hopefully it's in your area or there is some equivalent.

I'm still not convinced I want that thing on my trunk lid...

02-27-2004, 08:46 PM
Hi Gang,

XM Radio is great and the antenna is a must to get XM and I don't why all the fuss. My NM XLR looks fine with the XM antenna.

:nopity :nopity :nopity :nopity :nopity :nopity :nopity :nopity :nopity :party :flag

02-27-2004, 08:52 PM
I have just found out that since my XLR was one of the early ones and was not ordered with XM radio, was not prewired as is done now. Because of that, it was recommended to me that I do not put in an aftermkt unit and can't put factory unit in.
Since I have had the pleasure of driving with XM radio, it is a real disappointment.:cry

02-27-2004, 09:20 PM
Hi Folks,

I can't believe all this conversation over the XM antenna. I also can't believe that there is an better alternative to the factory antenna vs the system working. Not to mention that the factory antenna is not a bad unit.


03-02-2004, 04:15 PM
I have a Delphi Skyfi XM radio in my car (not a XLR) with the antenna "velcroed" on top of the dash. I have no problem with the signal. One thing that is nice about the Skyfi is that I can hear XM in my house with the home adapter unit.

03-03-2004, 08:55 PM
Hi Gang,

I can understand if one has to install an XM radio as an aftermarket and doesn't want to put any holes in the vehicle, the velcroing the antenna to the dash is OK. However, I am some what surprised the windshild glass does not cause some problems with reception.

In addition I have seldom found that going around pre-wired electonics in the auto world seldom turns out better.

Again, I think the XM antenna on the trunk lid work fine and is not all that bad looking. It's where the antenna is on my NM XLR.


03-09-2004, 05:26 PM
The XM antenna is dealer installed. Comes in a small box packaged up and left in the trunk for the technician to install during the pre-delivery inspection. My dealer does not drill the trunk and install the antenna unless instructed to do so by the buyer of the car. They also don't mount the front license plate bracket unless the new owner requests it installed.
I think the antenna looks terrible...can't believe that they can't come up with something that's small and not visible.

03-09-2004, 06:45 PM
Me neither.

They can hide the am/fm radio and the navigation antennas, so why can't they at least minimize the XM radio antenna if not hide it?

03-09-2004, 07:23 PM
What r u dudes talking about?
The XM ant. looks cool, is body colored and provides outstanding reception--get with and enjoy the tunes!

03-10-2004, 09:32 AM
The Ant is dealer installed only because Factory knows it is WRONG and their approach is "let the customer F. it up"
They should not be willing to sell and partially
install a product that they know is unacceptable,
and I hope they are taking on the responsibility of
finding a solution to THEIR problem.
In the meantime, my Ant will remain IN the trunk.

03-10-2004, 09:37 AM
I have to agree with CTSVMAN, but let me try to explain the difficulties in reception with satellite radio.

First a little background...There are a number of frequencies involved here. AM is the lowest frequency involved (kiloHertz), followed by FM (100s of megahertz). Both AM and FM are local and their signals travel in the low 100s of miles. Neither are particularly difficult to find through walls, ect. Antennas are designed to increase the gain of the signal and remove interference.

Your cellphone is a bit more difficult. The frequencies go to up approximately 1.8 gigahertz. The advantage cellphones have is that with towers the transmission distance is very short. Nevertheless, many new cars still come with external cellphone antennas. The XLR hides it's antenna attached to glass in front of the passenger seat but line of sight is still needed for clear reception.

For satellite radio, XM uses a downlink of 2.32GHz to 2.33GHz range - a little greater than digital cellphone. But, its transmission stations are 22,300 miles away, with one exception. Line of sight is again required. However, XM fills the holes where line of sight to the two satellites is not available by having repeaters. These ground repeaters also transmit in the 2.32-2.33 GHz range but at a lower angle to the car.

Anyway, the point of all this, is that there are a number of technical problems with an antenna that is inside the cabin and could be blocked from viewing the satellites. The problems become easier if ground repeaters are nearby (such as in cities) or the owner doesn't require almost-constant coverage.

For me, I'm still just amazed that I can pick-up a signal from 22.300 miles away without a dish. The way that is done is subject for another long email...

Finally, Sirius radio does things differently. Those signals are sent from three non-geostationary satellites that are in highly elliptical orbits. Frequencies are roughly the same as XM Radio.

03-14-2004, 07:22 PM

03-15-2004, 07:57 AM
Can you add xm after the fact to the factory system?

03-15-2004, 09:32 AM
There was another thread in this forum that had a good discussion of an after-market XM Radio add-on. The bottom line is you can but it will take around $3K in parts/installation and is not an official Cadillac/GM aftermarket option. Therefore, not all dealerships can or would be willing to do the modification.

The only other way to add XM right now is through an FM-modulated separate XM tuner. The tuner would play through the XLR FM. Sound would not be as good and channel up/down would only work on the tuner (not with the steering wheel buttons).

Bottom line is that if you want XM, order it with the XLR. Here is the link to the thread with the aftermarket XM Radio discussion...

03-15-2004, 06:43 PM
Here is my set up for my wife car ( it is not a XLR)
1) A Delphi SkiFy XM Radio unit ~ $149
2) A Delphi SkiFy Car Adaptor Kit ~ $60 (included XM antenna)
3) A Delphi SkiFY FM Modulator ~ $60

You can have a reputable audio installer to install the FM modulator to your radio. The FM modulator can be hidden behind the radio. The car adaptor kit connects to a small XM antenna that you can put on top of the dash.

Since the FM modulator is connected directly to the radio antenna, the sound is great. I have the XM radio connected directly to the aux input of my car radio (not a XLR) and could not find any differences between the FM Modulator and the direct method.

One thing you may have the problem is that where to put the XM radio unit in your car without making it looks bad..

I have an adaptor unit in my house which connects directly to a wireless transmitter. With this setup, I can hear XM around my house with a wireless headphones.

Good Luck