I have a 2008 C2S cab 997.1 and have been investigating installing a compatible Cayenne Sirius XM receiver in the existing MOST loop.

Two Porsche dealers as well as Suncoast all tell me it can be done, but that it does not work so well because reception is especially spotty, and they gently discourage me from attempting it. The results of Rennlist posters is mixed, with some of them expressing frustration with their own reception.

It appears that the problem boils down to antenna location, with most installations installing the satellite antenna just under the light plastic cowling below the wipers. Maybe that location is in the shadow of the metal roof, windshield, passenger, and driver when driving away from the pertinent satellite.

I asked one dealer how Porsche does satellite on the 997.2s and was told it is an external box, painted the exterior color, attached to the engine lid and run through the bowels of the car to the front. It doesn't look like a fun retrofit, and it sounds kind of ugly. (Does someone have a photo?)

So I started looking to see if there were any other non-metallic locations where an antenna could be hidden on my car with more open access to most of the sky. I have two candidates:

1. Attached to the underside of the plastic front bumper in the flattest area possible. It looks like a concealed wire run would be easy, but I don't know much about how much the thick bumper material would affect signal strength. Also, I can see some problems with attaching with proper orientation. And it looks only marginally better than the wiper cowling from a signal access point of view.

2. Since I have a cab, and the entire roof is almost entirely fabric facing the sky, it occurred to me there might be a place in the plastic top frame where I could install the antenna. I believe it would be relatively easy to run the wire back to the convertible top shelf and through the trim to the front of the car. I see two problems: a. The wire would have to be configured to accommodate the moving top without fatiguing and without interfering with the cab top motion. b. I am not sure of the materials used for 997-561-905-00 roof frame and 996-561-963-00 base (the cover that goes over the frame to make a smooth transition to the windshield). Does anyone know?

Which location would work best? Because I have a cab, would the location under the wiper cowling work more normally vis-à-vis a coupe because I don't have a metal roof?

 

I have the Sirius option (686) on my GTS, but see nothing as you describe.

 

I had my Sirius XM antenna mounted on the front bumper, concealed under the bumper cover on my 996. It worked beautifully.

 

The antenna is that little painted box at the rear edge of your roof.

 

Its a small antenna/LNA.....I mounted mine on the top of the dash inside the car, its over near the A pillar of the passenger side. No problems with reception. I was going to mount it as Nav-TV suggests, under the cowl and the small metal shelf where the battery resides. But I'm an RF engineer, and seeing all the metal on the sides, yes that will block the signal a bit. It a small black antenna/LNA. its fine to simply place it on the dash inside the car.

 

That's what I thought, too, but the OP said the dealer said it was on the lid. I should have known better to listen to what a dealer says, huh? Does it also serve as GPS antenna for the Nav?

 

That's where mine was on the -06 C4S. No reception problems at all and it's completely invisible.

 

I had a new head unit installed and the Nav and Sirius sat radio antennas where both located under the plastic cowl cover. The reception was real bad when I was driving next to anything like a building or trees so I moved the antenna to the outside.

I used some double sided 3M automotive tape to stick it on the outside of the cowl. Given the small size of the antenna it's barely noticeable. Without a roof or back window to mount it to there is not a lot of choices

 

Don't think it doubles as the Nav antenna - cars with Nav but no Sirius don't have the "box" on the roof.

 

I have a cab as well and mine is in the same location as pictured here. Has worked great - can't remember a single reception issue.

 

Great input. Many thanks to all.

There has to be a reason why 2 area dealerships as well as Suncoast are all leery of getting involved with this retrofit, all citing cases of poor reception on random installs. My suspicion is that antenna location is absolutely critical and the key to success.

I notice that the two successful installations cited above are (1) both on *top* of the plastic wiper cowling instead of underneath and (2) are *cabs.*

I'm thinking by installing the antenna on top of the cowling, it raises it over the plane of the top lid which could otherwise put it in a signal shadow if the satellite was in front and lower on the horizon. And I still suspect reception could be diminished with a metal coupe roof instead of fabric cab top if the satellite is high and towards the rear, which it would be nearly half the time.

It would be interesting to take a poll of people with 997.1 Sirius XM retrofits and their satisfaction with reception for coupes versus cabs.

What does an individual antenna cost? I'm thinking I might install 2 antennas if its cheap enough (one under the bumper cover, and one on top of the cowling), and try each of them out, one at a time, to see what optimizes the reception. Or temporarily start with one on the bumper for a couple weeks, then move it to the top of the cowling temporarily and compare?

Surely someone must have already done this before.

 

See https://rennlist.com/forums/997-foru...7-c4s-cab.html and https://rennlist.com/forums/997-foru...o-install.html which you may have already done.

 

I had it for 12 years under the wiper cowling of my 2000 Boxster S..... no problems at all. Note, they put it up high and pressed the underside of the cowling.

Edit: I implied above that I never had reception cut outs... this is not true. Buildings, dense trees to my south side.... etc. but I never considered this a serious issue nor did I consider moving the antennae. I share Ken's theories in his post below mine here.

Peace
Bruce in Philly

 

I retrofitted sat radio to my cab and here are my observations about reception. I was concerned too about reception so I tested it with the antenna below the cowl and also with the antenna on the dashboard top down. I drove the same route with the antenna in each position and subjectively judged satellite reception. I didn't see a measurable difference in reception quality. The signal cut out in approximately the same areas so I chose the more concealed method under the cowl.

I think that some of the variability in reception has to do with geographic location of the user. I feel like I had better overall quality in reception when I lived in one state vs another. This is just a theory that I've come up with from my own experiences. No clue if it is accurate or not. Another thought I have is maybe some antenna models get better reception than others and maybe that accounts for the variability.

Ken

 

You missed this one: https://rennlist.com/forums/997-foru...l#post12013366

Hidden underneath the cowling and very successful...on a coupe.