New Antenna Issues

I recently had my OEM stereo replaced with an Alpine CarPlay head unit. I got a pro stereo place to do it. As part of the work they did, they replaced my antenna base with one from a first generation Tiguan that has antennas for AM/FM, GPS, satellite radio and GSM (we didn't use the GSM.) The part numbers we used were 5N0 035 501 B for the base and 5N0 035 849 A for the appropriate mast. However, we have noticed that the reception is now very poor. FM stations that I could hear fine last week now have some static and we can't even find an AM station yet. Before I gave the stereo installer all the parts, I hand-screwed on the mast. I didn't use a wrench to tighten it but I thought I had gotten it on all the way. However, I just removed the mast a few minutes ago and noticed some white plastic in the connector that is partially concealing the metal contact in the mast. So, my question is can/should I remove that plastic? And, should I tighten the mast using a wrench? Or, should I be looking elsewhere?

The threads on the antenna mast make contact with the base.

In the ALH, that base was a powered amp from the radio. Perhaps the same ?

I did make sure the blue antenna power wire was attached. I am starting to think the antenna I have doesn't reach the bottom of the hole. The bottom of the hole is flat but the bottom of the antenna I have is concave. Also, because of the rubber at the base of the antenna, I can't figure out how to tighten it without ripping off the rubber. I've gotten it as tight as I can but it feels like it wants to go farther. Am I missing something? Or, maybe I ended up with the wrong antenna? Is there maybe a threaded insert that I am missing?

I just looked at my Tiggy's antenna - there is more exposed metal than just the threads on mine. Is that a Chinesium product or OEM? Also should just be snug by hand and not crazy tight.

The antenna base also has to have a good ground to the roof. I have seen a couple, with your problem, where the sharp points on the nut did not dig through the paint to make good contact. Took the antenna back off, sanded that small section (inside the car!) of the roof to bare metal, then reinstalled the antenna. Fixed the cars I had with this problem.

Also, how hard would it be to stick the stock radio back in? I'm thinking since there is a diagnostic mode on the radio, it may help figure out what is going on with the antenna.

Jason

I got the mast from ECS and I made sure to pick the one with the "Genuine VW" logo. I got the antenna base from there too, also with the "Genuine VW" logo. A pro car stereo place did the work, so I can ask them some of the other questions, but their work has been great so far. Unfortunately, I don't think I can test with the original radio. One thing I did notice after some additional testing is that if I remove the mast entirely, FM reception actually improves. Now, I don't want to run it this way since I still don't get AM reception yet, but my assumption is that this current mast must not be making proper contact and when it is screwed into the socket, it is actually making things worse by blocking the exposed metal bottom of the hole. I started looking at some closeups of some other masts, and almost all of them look different from the one I have. I think at this point I am going to try to find another mast to use for testing, ideally one with a completely flat bottom. What I'd like to find is that OEM Sharan stubby, but I can't seem to find anything but knockoffs and I can't find the VW part number for it.

Actually, I did find the part number: 7M0 035 849 E

Now let's see if I can find one that isn't a knockoff.

Could also be the wrong antenna. I remember a TSB for poor radio reception was a mix up of two different style masts. Look identical, but different resistors and wire wrap.

If the FM reception improves then there is contact being made (contact is blocking reception for some reason). Bottom of the mast is always cupped to fit the base. BTW - I looked at a Beetle and the mast & base look like yours.

As for ECS - I have gotten some "Chinesium" with VW official looking stamping, and other parts that have the VW stamping ground off. Not all bad from them, but a mixed bag of good and bad.

So, hard way to check antenna (since stock is not option) - check for 12V on the antenna cable at the antenna. Also verify antenna base is properly grounded. BTW - why can't you use the stock radio to test?

Jason

Regarding my original radio, I could go get it but I boxed it up and it's at a storage unit. Maybe it's worthwhile. I measured my mast thread length and the hole depth of the base, and it looks like the threads are 1mm too short. I tried my old original antenna, and it was too short too. I guess I should try and find an antenna with longer threads. Such is the fun of using newer model parts on older cars. At least the satellite radio antenna in the shark fin works great.

I may go get my original radio now for testing. I purchased an aftermarket antenna mast that had a separate thread barrel, the thinking being that I could insert the threads first so that I was certain I was making contact with the bottom of the hole. The antenna mast then screwed onto the remaining exposed threads. But, this had no effect whatsoever. I live in the middle of Portland, Oregon and with my original antenna base/mast I can get both AM/FM so I know it's not a signal strength issue. Is there anything different from an AM/FM standpoint between the original base and the newer base I installed, e.g. is there a booster in the original base that isn't in the 5N0 035 501 B base? I may also see if I can remove my new radio to make sure that the installer connected the blue powered antenna wire. I am reluctant to do so since I'm sure I won't be able to get everything back in as nicely as the installer had it. It was mentioned before that I could test 12v on the antenna wire at the roof. Could I also test this with a multimeter by using the bottom of the mast hole or does the 12v not go that far?

Maybe I missed something? I was looking on the VW parts site and I noticed something that I didn't order, part 5N0035552D. It is labeled as "antenna amplifier" or "antenna booster." Was something like this already in my car or is this something I might need to order? Since a pro installer did the work, I didn't see what was there originally.

I should mention that the roof antenna on my Tiggy is for GPS and SAT. There are wires in the side windows for terrestrial radio (AM/FM) . I do know the whip antenna should only be there for AM/FM reception, but it's possible Tiguans use a combination of roof and glass antennas for AM/FM.

I need to dig out my old SSP books and do a little research.

Jason

PS: what about you original antenna? Try putting it back in and see if the AM/FM reception comes back. At least then you will know the radio and wiring is all good.

D'oh, this may have been all for naught. The installer reviewed their notes and they now think that they used the red GSM connector instead of the grey AM/FM connector on the new base. I'll know for sure Friday. Luckily, they had some other work to do this weekend anyway that involved dropping the headliner. I'm having them run all the wires for the rain sensor + auto-dimming mirror that I acquired.