SoCal C2S

Here is where I installed the antenna.....zero reception issues.

JustinCase

I recently installed the Porsche Cayenne XM receiver with my PCM 2.1 in my 2008 C2S Cab. I spent a great deal of time experimenting with antenna locations, and I now have some pretty solid conclusions.

First, though, I would like to thank this forum and all the members who originated or contributed to the various threads on this subject. ALL this information was quite useful and contributed no small amount to my successful installation.

I actually installed *two* antennae to be used one at a time. Both are identical AudioVox XMicro2 (@ roughly $13.00 each).

The first antenna was installed exactly like described in Musclehedz101's superb How-To post of 10-02-2010 (https://rennlist.com/forums/997-foru...ml#post9717439) -- epoxied completely out of sight as high up as possible ON THE UNDERSIDE OF THE WINDSHIELD WIPER COWL. For esthetic purposes this location is by far the best.

Many forum posters swear by this location as working perfectly well, and it does work, but I found it highly susceptible to drop outs caused by the signal shadow of close-by buildings or trees. This is especially significant to me because I live in the foothills of the Cascades near Seattle. Almost everywhere I drive is like driving through a narrow corridor of very tall trees or through valleys where parts of the road never see direct sunlight year round because of nearby peaks. The drop outs in these areas are maddening and almost completely negate any value of satellite radio. The pertinent satellites are just too low on the horizon for an antenna that just barely peeks above a mass of surrounding metal.

However, on major highways and open, flatter land, this location DOES work perfectly well. Going back and studying the locations of posters for whom the under-cowling location works well, I see a preponderance of flat and open places like Texas, Kansas, Florida, and a smattering of Northeastern states. Posters who have complained about this location live in places such as the Northwest, like me. *Now* I get it.

The second antenna was tried in place of the first antenna in as many practical locations as I could think of:

ON TOP OF THE WINDSHIELD WIPER COWL -- not much different than under the cowl. There may have been a slight improvement, but not one that prevented me from going mad because of all the drop outs on the roads I regularly drive where I live.

ON THE DASHBOARD UP AGAINST THE WINDSHIELD -- better, but still way more drop outs than either of our other vehicles (an Acura with factory satellite and an old Dodge pickup with an FM modulator [!]). Still not acceptable in our area for me or for most people.

AGAINST THE WINDSHIELD BEHIND THE MIRROR -- about the same as on the dashboard, sometimes worse depending on the direction driven.

IN THE BACK GRIP OF THE CABRIOLET TOP LOCKING MECHANISM (directly under the headliner) -- Looking in PET, I noted that the front segment of the cabriolet folding top looks like a honey comb piece of plastic:



Since there is no place higher on my car than the back of this front segment, I wondered if I could place my antenna inside it for the best possible reception. But since this would involve nearly completely disassembling my cab top (deemed "not very practical"), I thought I would simulate it by placing the antenna between the hand grip in the back of the cabriolet catch trim cover and the headliner. Satellite reception was worse and less predicable than under the windshield wiper cowling, I presume because of the mass of plastic and some metal parts.

DIRECTLY BETWEEN THE HEADLINER AND THE FRONT SEGMENT HONEY COMB ROOF FRAME -- No better, probably for the same reasons. I still wonder if embedding the antenna at the top of the honey comb roof frame would be ideal for BOTH reception and esthetics, but I'll wait until I have to replace my cab top before checking this out. Other "gumption getters" include configuring the antenna wire so that it folds neatly with the top without fatiguing, and running the wire all the way back up to the equipment in the trunk.

THE TOP OF MY HEAD WITH THE TOP OPEN -- Works great and confirms that an antenna mounted just under the canvas of the top in the front segment might work, but deemed uncomfortable and impractical. It also looks ridiculous and the tape tended to leave a bizarre shadow in the tan of my bald spot.

ON THE TOP FRONT OF THE WINDSHIELD SURROUND -- Out of frustration, I stuck the magnetic base of the antenna to the top of the windshield surround, just out of way of the closing top, and lo and behold, it worked nearly as well as the satellite radios in our other cars!



View with the cab top down




View with the cab top up




Close up

After deciding this location was about the only practical one in my geographic region, I went ahead and tucked the antenna wire under the rubber seals, under the windshield cowling, and through the grommet, tying the connector end to the end of the under-cowling antenna -- both accessible through the removable cover above the satellite radio receiver and navigation units.

My reason for leaving both antennae available for easy connection is pure vanity -- when I go to PCA events I can pull the windshield surround antenna off and chuck it in the trunk (so people don't make fun of me) and still use the under-cowl antenna. After all, most events (except tours) occur in more open areas where the under-cowl antenna works well.

Another reason for leaving the under-cowling antenna is in case the windshield frame antenna wire fatigues with repetitive openings and closings of the top. If this happens, I can switch antennae in about 1 minute without disassembling anything.

I know people will make fun of my exposed antenna from time to time. After all, these are some of the same people for whom a front-mounted license plate (which I have) or amber front side marker lights (which I don't have) are signs of Porsche impurity. Yet many of these same people purposely show up at the track with all sorts of irregular GoPro mounts scattered across the surface of their cars. Also, many of them drive 2009 and later cars with the satellite radio option sporting larger and more obtrusive antenna housings on the roofs or back lids of their cars. "Practicality" is truly in the eye of the beholder. I guess at my age, I almost don't give a damn.

During my experiments, I discovered one more interesting aspect to my OEM satellite radio receiver -- it buffers (stores) about 10 seconds of the next content at all times so that very short drop outs are covered over and never noticed. The implication of this is that the faster you drive, the fewer drop outs you will have and the shorter their duration. This is an empirical observation and not a recommendation.

I believe this antenna location problem is why Porsche remains generally unsupportive of this upgrade -- it will work for some, but not others, and as a standard SKU it would generate a drumbeat of complaints and "warranty" issues no manufacturer wants.

But I now have reliable Sirius XM satellite radio in my 2008 997 C2S cab, in the hills of the Pacific Northwest, and I am very happy with it.

dolphinzilla

how did you route the antenna cable into the cabin ??

JustinCase

The wire side faces the back of the car, with the wire tucked under the rubber weather stripping across the top of the windshield where the cab top lands, down the right side, out of the weather stripping at the bottom of the passenger side of the windshield, under the passenger end of the windshield wiper cowl (where the extra is coiled up and wire tied), with just enough going through the firewall through the large, unused rubber grommet, and over to the antenna splitter plugged directly into the Sirius XM receiver velcroed to the top of the Navi unit. Note that the antenna wire *never* enters the cabin.

Since I wrote my results above, my son made fun of the "aftermarket look" of the antenna, so I painted it Midnight Blue Metallic so it matches the car. It probably still looks "aftermarket," just maybe less so.