XM/Sirius Aftermarket Antenna Location?
 

Last Wednesday I had a new Kenwood DNX6960 installed in my '08 coupe. It replaced the factory standard non-Bose audio system with OnStar and XM. The factory speakers and amp are being utilized. Everything works great except the XM radio. The XM antenna (as well as the new nav GPS antenna) was installed on top of the center dual a/c ducts (atop the one on the left). I am now experiencing extreme loss of signal with the XM (the navigation works great, bye the way). It is so bad that reception is now only intermittent. The interruptions are madening. It works fine as long as the car is sitting still, but as soon as it goes in motion, the signal begins to fade in and out. It does it just in my residential neighborhood with no tall obstructions around. Then you can go for two or three minutes and it is good until it fades again. Hardly ever had a loss of signal with the stock XM set-up (I know that the stock antenna is located in the outside mirror pods). Where do you guys mount your XM or Sirius antenna when you swap out the factory set-up? And do you get good reception? I am located in the Southeast US if that matters. Is there any way to re-use the factory antenna? (The new XM tuner was located next to the fuse block in the passenger foot well).

I had the same experience with my 2007. Bought an xm antenna online and installed it on the glass at the top of the rear hatch, virtualy invisible. Cured the drop outs completely. The only time I ever had another dropout was going thru a tunnel. Best $20 I ever spent!

i would like to know also where the best hidden place to put this is?:lurk:

Did you consider using the OEM Sat antenna connection, the yellow/orange one, that's the 'normal' solution for the SIRIUS upgrade.

Not sure that Sirius is an upgrade, however I installed an XM tuner (Kenwood KCA-XM100V XM interface and CNP200 XM mini tuner) in the passenger side footwell next to the fuse box. In my post above, I asked if it was possible to use the factory XM antenna.

I installed both my GPS and XM ant in exactly the same spot. I replaced the standard head unit in my 08 with a Pioneer Z120 and both XM and GPS ant are exactly where yours are. I have no problems with recerption at all. Based on what you are experienceing I would suspect a bad ant or a loose wire esp since it only happens with the car in motion. I would have the installer replace the ant and see if that makes any difference.
Also make sure the installer put the thin metal stick on plate down and both ant are sitting on it, if only the GPS ant is on the plate and not the XM ant that could be the cause of the issue also.

Thanks a lot for the suggestions. We finally solved the issue late this aftenoon after several hours of experimentation. The solution turned out to be relocating the antenna to the base of the passenger side "A" pillar. We moved the antenna around to different locatons inside the car, then went out driving to try them until we found one that produced no loss of signal or "drop outs" The "A" pillar fix turned out to be the one that worked. We popped off the "A" pillar trim on the passenger side, located the "wart" antenna at the base of the windshield pillar in the corner and put the trim back on. It is totally concealed and works great. I drove the 115 miles home from Madvettes Motorsports in Murfreesboro, TN to my home in Huntsville, AL down I-65, through the southern Tennesse Hills and into my garage without once experiencing a drop out, or loss of signal. It was strong all the way. Neither Dave Hale of Madvettes or Dennis at Double D Mods has a clue why this particular car was so hard to locate the antenna in. Both have done many, many installations in the C6 and have never experienced a problem with reception with the antenna mounted over the center a/c ducts. It remains a mystery.

I initially had my aftermarket SIRIUS antenna on top of the center AC ducts. When I first installed it the reception wasn't terrible, but I had enough drop outs that it was annoying. Since I wasn't using the center speaker I eventually took it out (to remove the large magnetic metal shield covering the antenna), reception improved a lot, but I still had the occasional unexplained drop out. I eventually fabricated a small metal bracket out of sheet metal that sits in the same place as the original center speaker, it's 1/2" deep and held in place by 2 of the 4 speaker mounting screws. My sat radio reception is now very good.

Thanks, Mark, that is good information. We did take out the XM tuner today while trying to nail down the signal loss issue and installed a Sirius SCC1 to see if amybe the XM tuner was the issue, but got the same result with the Sirius until moving the antenna to the base of the "A" pillar. I left the Sirius tuner in the car. Did not want to pull the HU again to change back to XM. Now I gotta call XM and deactivate that tuner.

That works really well if you are installing the new tuner in the same postition/location as the factory XM tuner that you are removing. And you can do this if all you are doing is changing from factory XM to Sirius. All you need then is a Sirius SCC1 tuner and a XM dual, to Sirius single, antenna adapter and you can plug the factory XM antenna right in to the new Sirius tuner. But it won't work if you are changing out the head unit to aftermarket. Problem is that the lead on the required XM interface box that plugs into the new radio is not long enough to reach the front of the car from the factory XM tuner location. We had to mount the new tuner in the passenger side footwell due to the short cable supplied by the maker of the new tuner (Kenwood) so that it would reach the back of the new radio. This also turned out to be the case with the new Sirius tuner. And extension cables are not availabel for the XM tuner interface box. (I did not check on extensions for the Sirius, but I imagine I would get the same answer). Thanks for the reply, though. ;)