thumper Posted November 6, 2008 Report Share Posted November 6, 2008 i just put this into my 07 vw gti, and there is no AM radio signal (i listen to AM mostly for news/sports/traffic reports). the was told that my car has 2 antennas... there is one on the roof out back, and another in the glass. the F90BT only has the one connection. is there any way of getting the AM signal back? i have am reception when the stock deck was swapped back in. Quote Link to post Share on other sites
mikeinnj Posted November 6, 2008 Report Share Posted November 6, 2008 I have an 07 Jetta with whip antenna (No shark fin) and don't get any AM stations either. I did the install myself and used the motorola to standard antenna adapter. FM is just fine, but no AM and I am about 100% sure that I do not have two different antennas in the car. Quote Link to post Share on other sites
thumper Posted November 6, 2008 Author Report Share Posted November 6, 2008 i'm not by any means knowledgable in this sort of installation, so i may have gotten the facts wrong. the installer showed me the antenna wire from the car, and there were 2 connectors on it. he said one was for the whip antenna, and the other is for the imprinted antenna in the back window. the pioneer unit only had the one radio connector. what is even more odd is that while the car was in his installation bay, it was still able to get a decent enough signal to be heard, albeit with some static. but once everything was buttoned up and i was sent on my way, the signal faded completely and i couldn't hear anything at all anymore. i don't know what else i've missed Quote Link to post Share on other sites
skicrave Posted November 6, 2008 Report Share Posted November 6, 2008 It's called a diversity antenna. Rummage around in the RNS510 forum on VWNavi.com and you'll be able to find instructions on how to restore your AM using an adapter. Quote Link to post Share on other sites
GQRilla Posted November 6, 2008 Report Share Posted November 6, 2008 Likely issue is installer may not have used the proper antenna adapter. We use metra 40-EU55 which accepts a power antenna turn on trigger activating the vehicle's powered antenna. YOU DO NOT NEED BOTH ANTENNAS PLUGGED IN!!! Other manufacturers make the same thing which work the same and you can find them on the internet I'm sure but I won't recommend or refer since I work in retail car audio and yes, it hurts us. Quote Link to post Share on other sites
thumper Posted November 6, 2008 Author Report Share Posted November 6, 2008 thanks... not trying to hurt anyone! Quote Link to post Share on other sites
thumper Posted November 8, 2008 Author Report Share Posted November 8, 2008 just came back from another installer. they used a metra equivalent as described above but... fm reception range improved, but no success with the am frequencies.... again, help? Quote Link to post Share on other sites
terron Posted November 9, 2008 Report Share Posted November 9, 2008 you could always go buy an antenna from the local auto shop, would save you one heck of a headache but might look tacky. Quote Link to post Share on other sites
thumper Posted November 9, 2008 Author Report Share Posted November 9, 2008 what do you mean by getting another antenna? as in replacing the oem roof-mounted whip antenna that's currently on the car now? Quote Link to post Share on other sites
gjas18 Posted November 9, 2008 Report Share Posted November 9, 2008 When you installed the power antenna amplifier adapter (Metra) where was the blue power wire coming from the adapter spliced? Quote Link to post Share on other sites
terron Posted November 9, 2008 Report Share Posted November 9, 2008 what do you mean by getting another antenna? as in replacing the oem roof-mounted whip antenna that's currently on the car now? http://www.crutchfield.com/g_232750/AM-FM.html?tp=3449 Quote Link to post Share on other sites
thumper Posted November 9, 2008 Author Report Share Posted November 9, 2008 the installer attached it to the radio output of the deck. It gives the antenna 12 volts once you have switched the radio on? Quote Link to post Share on other sites
gjas18 Posted November 9, 2008 Report Share Posted November 9, 2008 There's your problem... The power antenna lead from the Metra thing needs to be attached to the ACC lead. There is not enough power provided on the wire coming out of the deck to power the antenna amp. I had this very same problem in my 2008 Rabbit. Its not the voltage that matter so much as the amperage getting to the signal amplifier. Amplifiers require a good amount of power as seen by the massively thick wires running to speaker amplifiers. That wire coming out of the deck only provides 500ma of power. (same as a usb port on a computer) Where the ACC lead will provide as much as the amp requires. Getting another antenna would not solve the problem since #1 I have no idea which antenna the wire that fits into the metra harness goes to. (even the wiring diagrams of the car don't really distinguish this) #2 Even if the one plugged goes into the whip antenna it would still go through the antenna amp. If the antenna was replaced you would still get terrible AM reception. The only way to fix it would to be for you to rip apart the interior of your car and run your own wire to the deck. With the billions of airbags these cars have in the pillars, have fun with that one. Quote Link to post Share on other sites
gjas18 Posted November 9, 2008 Report Share Posted November 9, 2008 I have an 07 Jetta with whip antenna (No shark fin) and don't get any AM stations either. I did the install myself and used the motorola to standard antenna adapter. FM is just fine, but no AM and I am about 100% sure that I do not have two different antennas in the car. You probably do have two antennas. After about 2006 (MkV's) most if not all VW's have what is called a diversity antenna system. The radio gets a signal from two antennas (hence the two wires) at slightly different positions on the car, usually the whip/stubby and the imprinted on the back window (sometimes it will be two antenna's imprinted on the back window if there is no whip). The radio will select whichever antenna has the better quality signal and use it switching between antennas whenever it deems necessary. Some cars, mainly higher end (passat, tourag) and audi, will have a antenna "brain" usually mounted in the trunk or hatch that controls the diversity system instead of the radio. The advantage of these systems is that an aftermarket stereo can still take advantage of the diversity antenna system. Some of the lower end cars may also have this if they have the super new touchscreen NAV from VW <-- not entirely sure on that though. The reason for this system is really complex and has to do with the phases of the incoming signal being slighty different at two different point and paths they take to get there. To sum it up its unlikely for both antennas to be blocked or suffer from attenuation at the same moment. so by having two antenna's your likelihood of having good reception is much higher. Quote Link to post Share on other sites
thumper Posted November 10, 2008 Author Report Share Posted November 10, 2008 hi... i just talked to the 2nd installer online and this was his response: Here's the thing...the blue/white wire is not powering any factory or aftermarket amps. Its not connected to anything. So unless the amplified antenna requires a ridiculous amount of power to operate (which it does not as we have seen with amp'd antennas for the past 20 years) then I see no reason to move that wire to ACC. Now, I can take it apart again and move the antenna wire to ACC but I sincerely doubt it would make any difference at all. sorry for all the confusion... i'm just trapped between what he knows from experience and what is being said here... and i still have no am reception i just want to be sure of this because he has to charge me for time/labor evern time i go back. Quote Link to post Share on other sites
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