SQLGuy

Hi folks,

I'm adding a '89+ "bee sting" style antenna to my '88 S4 to make up for the windshield antenna I lost when I got a new windshied a couple of months ago.

I'm using Porsche original parts for this, same as were stock on the 89 and up cars.

Just thought I'd share a few gotchas I've run into so far:

1. Although the antenna is shown with the cable in pictures on some web sites, when I ordered it, I got just the antenna. The cable was a separate purchase.

2. Not only do you have to drill a hole through the roof (of course this is obvious), but it is a SQUARE hole (14.5mm on a side). I drilled a 9/16 hole, starting with smaller bits and working my way up to a Silver and Deming 9/16. I then used an air-driven metal saw to cut the corners of the hole and did the finish work with a small file.

3. There is a metal plate welded to the roof where the sunroof motor mounts. There is about 3/4" of space between this plate and the inside of the roof. On my '88, there was an oval hole in the plate that was more-or-less aligned with where the mounting hole came through, but that hole was actually too small to fit the mounting nut for the antenna through. Once again, the metal saw was needed - to open the hole up enough to get the nut through.

4. Even with the hole opened up, it wasn't anywhere near, and couldn't reasonably be made anywhere near, big enough to allow any 17mm wrench or socket through to tighten the mounting nut. What worked for me was grabbing the nut by the edge with a pair of very thin needle nose pliers (tip of one jaw outside the nut, other jaw inside the nut). This made it possible to get the nut started on the threads of the antenna. To tighten it finally, I used a heavier pair of needle nose pliers. I think the later 928's have a bigger hole here, but they probably still need a special tool to tighten this nut.

At this point, the antenna is mounted, but I haven't run the cable yet. I'll update this once the rest of the job is done.

Cheers,
Paul

Ninespub

Sounds like a whole lot of work and I hope you are successful with your efforts. I'm considering pulling my bee stinger off and welding up the hole when I go into a full body bump & repaint this winter. Prolly go "hidden antennae" or go with a sirius/gps module in the high stop lamp; or maybe a shark fin antennae on the top of the rear hatch. I think Keith Widom routed his sirius in the high stoplamp IIRC in his flush-mount center console update with the double din receiver.

slate blue

Make sure you rust proof well around the areas you have cut, good place for rust to start.

Greg

SQLGuy

That's a mixed bag. If you rustproof, then you don't get good ground contact for the antenna.

The antenna has an O-ring'ish (square) seal that seals onto the painted surface, and I also added silicone grease there to help seal. But I kept the inner edges of the square hole uncoated to get a good ground to the pot metal of the antenna base.

SeanR

Need some pictures of this process.

StratfordShark

I used this very thin wrench (in UK termed a box spanner) which fits the hole and has plenty of reach to get on that antenna base nut.

SQLGuy

Yes, but you have a '91, which came with a roof antenna.

In my '88, the original hole from the bottom wasn't even big enough to slide the nut itself through - sideways! Also, if I had positioned the antenna a bit forwards of where it is from the factory on later cars I might have had room to open the bottom hole up enough for such a tool, but with the stock location I would have had to cut away some sunroof mechanism support, which I didn't feel would be a good idea.

Pictures soon....

slate blue

By SQLGuy

Do you know what the factory did? I don't but would have thought there was no bare metal?

Greg

SQLGuy

No, I don't know.

What I do know is that the amplifier is in the base of the antenna, and there is only one power lead. So, regardless of needing a good ground for good FM reception, you need a good ground to the antenna base just to power the amplifier. Since that ground is coming from the roof, there has to be bare metal - maybe not steel, but at least some exposed metal that's attached to the steel.

SQLGuy

OK, antenna done. Here are the pictures.

To run the cable, I removed the top screws and the seat belt rosette screws from the B-pillar cover, and also removed the two screws from the headliner near the sunroof motor. This allowed me to pull things down and away enough to fish the cable through taped to a length of 12 gauge copper ground wire. I then tucked it under the edge of the B-pillar cover (cable is grey foam covered thing in 4th picture), and ran it under the door sill "928" cover. Up front, I ran it behind the carpet on the side of the passenger footwell and out a hole I had cut by the computers. From there it was up and over behind the glove compartment and down into the center console.

Seems to work fine so far. We'll see how it does around town and out on the highway in the next few days.

Cheers,
Paul

SQLGuy

Actually, I was thinking about this while I was at the gym, and power for the antenna could use the signal ground (shield) of the cable. This is generally not considered a good practice, as shields are meant for shielding, not for current carrying, but the factory could have relied on that if they had all the metal at the mounting point coated/painted.

I still prefer having a good ground for both signal and power at the mounting point, but I can't say that it will definitely make a difference either way.

Mrmerlin

usually the nut has a serrated washer thats installed between the nut and the car body, atleast on the roof antennas i have worked on

SQLGuy

This one does not. It does have teeth on the nut itself, but I wouldn't count on them to neccessarily grind through the innner roof coating by themselves and guarantee a good ground.

FWIW, I did add a spray of pure silicone (not WD-40) from the underneath after the antenna was in place, to help shield the parts from moisture. I'm still counting more on the seal and silicone grease up top keeping any water from getting in there in the first place, though.

andy-gts

good write up I wasl thinking of replacing the antenna with something shorter on my car soon. this helps
alot

StratfordShark

This is the serrated nut from my MY91 antenna. I don't remember a washer being there - the nut went right up to the roof and at the time I assumed the teeth were to ground the antenna.