760list

I'm sure this has already been discussed, but I am wondering where to mount a roady antenna. I'm getting a SL500 for a night to see if i will actually be confortable in a SL. I'm 6'3 210, and am hard to please for comfort. Thanks. Post pics if possible.

RajS

You should be alright if you lower the seats all the way. I am 6'1" and fit very comfortably without even having the seat all the way back.

CASL55

Here are pix of my Sirius antenna installation that's hidden from view. Since XM antennas are usually somewhat smaller than the Sirius ones, this approach should work for XM as well. The coverage is not as good as a rooftop antenna, but that approach is not possible on an SL. When driving north-west, tree cover sometimes causes dropouts, since the roof blocks access to the southern sky when the car is pointed in those directions.

I think the ultimate solution would be several antennas connected to a box that instant-to-instant picks the one with the strongest signal. I don't know of such a box.

Jim

The Godfather

WOW! That's very ingenious!!!! I like it!

JackStraw

CASL55,

Thanks for posting the pictures, this is exactly how I want to mount my antenna. Where does the antenna cable enter the cabin? Also, what percentage of the time are you getting poor reception or no reception?

CASL55

JackStraw,

Well, with Sirius and XM, there is no poor reception that I’ve noticed. It’s either good, or you get dropouts. Sometimes the dropouts are longer than other times. My standard of comparison is a GMC 2500HD truck that I bought with factory XM radio installed using a roof-mounted antenna. I can drive around Monterey all day in the truck and only have three or four dropouts. In the Mercedes, going certain directions, it’s bad enough that I just listen to something else. Going east or south, it’s actually better in the SL than in the truck, but going northwest, it’s fair if there are no trees around, and not acceptable at all with significant tree cover.

As to the wire routing, I don’t know how they snaked it through. I told my local Mercedes dealer where I wanted the antenna installed, and they did the antenna installation when they put the Sirius radio in the car. They initially attached the antenna to the little black plastic shelf that is underneath the hood opening and doesn’t go up and down when you open the hood. Reception was not good at all. Moving the antenna up a few inches by strapping it to the grill on the hood as you see in the pictures made a huge difference.

Note that I’m not using the antenna that comes with the Mercedes Sirius radio kit, but rather an aftermarket antenna. That’s because the cable that comes with the antenna is too short to reach from the place where the radio goes behind the driver’s seat to the underside of the hood. I think I’d get better results with the factory antenna if the cable were longer. My reasoning is that I couldn’t find a two-wire antenna in the aftermarket, and had to install a two-wire-to-one-wire splitter to make the aftermarket antenna compatible with the Mercedes satellite radio. The splitter is passive and therefore has some loss, and the connectors have loss. So, I think you’d get a stronger signal with a two-wire antenna with a longer cable. I read somewhere that someone had used the antenna for another DaimlerChrysler car and it was long enough to reach up under the hood. I don’t know what car the antenna is for, or I’d go that route myself.

Good luck, and keep me posted on how it works out for you.

Jim