StratfordShark

I had very poor FM and AM reception (been like that since I've had the car) so checked roof antenna today.

I checked the amp feed and it's getting switched 12V. But when I unplugged the co-ax lead I could see very bad corrosion on the earthed connector and the inside of the plug from the antenna. After cleaning up as much corrosion as I could with Dremel I reconnected and was rewarded with fantastic FM reception. So far so good.

However AM reception still poor so wonder if good FM/poor AM is sign of bad amp? Thought I might as well try to remove existing antenna in case I have to replace it.

Removed sunroof motor and the gear reducer. The metal sunroof lines block access to the nut, so before I do any damage what's the next step to get nut access (I have a box spanner to fit the nut)? The gear reducer is mounted on two rubber buffers which you can see loosened in the photo. If I can get these out (that looks tricky too) does it make it easier to move the metal lines?

Please can anyone who's been there and done that with the roof antenna advise how to get to the nut without risk of damaging the sunroof mechanism?

Mrmerlin

the sunroof mechanism is blocking the antenna and if you remove the hardware on the sunroof drive tubes you should be able to pull them down far enough to insert the wrench to remove the nut.

Randy V

I hope you continue documenting the replacement with pics.

Many of us need to do this job.

Leon Speed

Yup

My reception was bad until I unscrewed the connector on the outside (in your third picture) and moved it all the way back so that it wasn't touching the metal on the outside. Go figure

StratfordShark

I'll try that too!

StratfordShark

Well I tried unscrewing the metal connector but no difference.

However I did discover that with the amp 12V disconnected, the reception improved! Conclusion is that the amp is bad, and that the amp is more important for AM than FM signals. To remove the antenna I created enough leeway to move the drive tubes by dropping the motor and letting it hang by its supply wires (seemed safe to do that for short period) after removing the front and rear support brackets.

The rear bracket is held by a single screw and it just hangs down after removal.

To get at the base nut there's only just enough clearance pushing the lines forward to get a hollow box spanner (17mm) onto the nut. You just thread the co-ax and power connectors through the box spanner before offering it up to nut which I could undo by hand. Once it's loose just grab the wires to stop the base rotating and flick the nut with long nose pliers to get it off completely.

Will look around for antenna options now. Understand VW Golf and possibly new Beetle antennae fit, though I'm not sure if connectors have to be modified.

VehiGAZ

I just went through this process myself, and I have some pics and other info to add, but I must do it from home later where the pics are. The "box spanner" our friend from across the pond refers to can be purchased at your local plumbing store or Home Depot. I will post a pic of the set as it appears in the package for your shopping convenience.

I was able to locate a small supply of coax wire adapter/connectors which will let you connect a new, slide-in style coax connector from a new antenna base to the screwy screw-in style one Porsche put in our cars. Without this wonderful little connector, you either have to replace the entire coax wire between the roof and headunit, or you have to cut the coax antenna wire and put a new slide-in connector on it. I will be reselling the 3 extra ones I bought...

Stafford, I didn't even think to use the Dremel to clean up my corrosion. I will give that a try at both the antenna end and the HU end to see if I can improve my still-miserable reception...

StratfordShark

Hi GAZ,

I picked up the antenna from a Golf Mk 2 today (believe it's known as "Rabbit" in USA).

Funny you should post about the adapters. Later on I dropped into auto parts store looking (without much expectation of finding something) for adapter. They had exactly the one you mention -male co-ax plug to screw on female. I could have cut up the new antenna lead and fitted the old connector but I always find co-ax fiddly and having adapter is great.

The 12V supply is a male spade connector on new antenna but it's very easy to splice on the female connector from old antenna.

Tried it electrically tonight and it works fine. The base mount has a smaller thread than original, and it doesn't have the square shape base of original. I don't know if filling the square hole in roof is essential to keep things watertight, or if the rubber gasket on base of the VW antenna will be sufficient to keep things dry. I wonder if the hole is square just to help fitting (antenna doesn't rotate as you tighten nut).

Will complete install tomorrow.

VehiGAZ

Not anymore... they are switching back to "Golf" thankfully...

VehiGAZ

Wow - I am impressed! I searched the web exhaustively only to find one company that might have them (based on their rest of their inventory), but I had to work through them to their supplier, then worked with them again to get the item temporarily listed on their site so they could process the order! Since it was such a PITA, I was hoping to corner a corner of the market by ordering extra converters and cover the cost of the one I needed.

StratfordShark

Yes and the ironic thing is that the parts store I went to isn't normally very well stocked for unusual/low demand items.

Anyway out of curiosity I just opened up the base of the old antenna to take a look at the amp. Found something out of a sci-fi/horror movie in there! The material feels papery to touch, like a solidified foam. I wonder if it's the original encapsulation of the material of the amp which has decayed? Anyway I'm not surprised the amp wasn't working under all that gunk.

Truly FUBA

Andy E.

The replacement antenna ***'y for the Fuba is mfd by Hirschmann. One of the differences on the Hirschmann antenna base is the absence of the small square cast stub present on the Fuba threads which helps sit the housing onto the chassis. This prevents the antenna base from spinning while tightening the lock nut from below.

I replaced the roof-mtd antenna ***'y on my friend's '90 S4 and later wished that I had never offered to do it in the first place. A job for the patient.

VehiGAZ

Ok, here we go...

1) The tool you need for this job is a 21/32" "shower valve socket wrench" (shown in pic below), which is close enough to 17mm to wiggle onto the nut. I got it in a set of them from Home Depot for about $25.

2) As StratfordShark said, you feed the coax and 12v pigtails (shown in pic below) from the antenna through the socket and use the metal rod that comes with the kit to remove the antenna base nut. It's pretty easy, really.

3) The converter cable I found is pictured below, as are its two ends.

Sorry for the crappy cell phone pics.

If you want one of these, PM me. $30 shipped to anywhere in the US. Please contact me for shipping out side the US.

StratfordShark

Finally an example where we're not being ripped off in Britain!

Convertor cable here (Halfords, looks identical to one in photo) was GBP 4.99 or about $7.90 inc sales tax.

Not trying to undercut you GAZ (I'm not going in auto parts export business), just pleased to find we're paying less for once, and from a store we nickname Halfrauds as its merchandise isn't notably keenly priced.

StratfordShark

As Andy says the base of the antenna I got (for VW Golf) doesn't have the square stub. Original and replacement compared in photo (by this time I'd removed base gasket from Porsche/Fuba part to examine amp).

I can get round the rotation problem (no pun intended) by having helper hold antenna from above while I tighten. I'm a little concerned about possible water leaks through the aperture though, as the original square stub filled hole and had a square sealing gasket.

Any opinions please on whether the rubber base of new antenna (more flexible than aged old one) will provide sufficient seal?