Just got my '06 XLR on the road and the FM reception is terrible. Is the antenna incorporated in the windshield or somewhere in the trunk? Anybody else having trouble with FM?

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Mike,

XLR uses a diversity antenna system. The FM antenna consists of a twisted pair attached to a foil ground plane mounted to the underside of the rear decklid beneath the faux rat fur cover. There is an upgraded antenna kit available (I bought one) that mounts to the top of the rear decklid (never installed it because I couldn't bring myself to do any onshore drilling. It looks like the "wart" but has a four-inch stick antenna on it, and has a modified ground plane that adheres in place.
CC

From reading in the forums, I thought that this was only an AM static fix. Will it also address FM? Also, searching through forums, the only FM reception complaints are from owners of '06 XLR's. Even local stations costantly fade in and out.

From reading in the forums, I thought that this was only an AM static fix. Will it also address FM? Also, searching through forums, the only FM reception complaints are from owners of '06 XLR's. Even local stations costantly fade in and out.

Must just be certain cars. I have an '06 and have not had any problems with AM or FM reception.

I removed the cover inside trunk lid and checked things out. Wires look good. Module has a small co-ax going in and when I touch a wire to it, reception goes good so I think antenna wire is good to here. The thing I didn't like was, on the module their is a 2 pin power connector and when the radio is on I get 3 volts across the 2 pins. If I measure from 1 pin to the plane ground I get 12 volts. Could I possibly have an open ground or wire broken somewhere in trunk harness?

Maybe. My FM reception is great. I have an 04. It amazes me how good it is. I wish my work truck had as good of reception.

I removed the cover inside trunk lid and checked things out. Wires look good. Module has a small co-ax going in and when I touch a wire to it, reception goes good so I think antenna wire is good to here. The thing I didn't like was, on the module their is a 2 pin power connector and when the radio is on I get 3 volts across the 2 pins. If I measure from 1 pin to the plane ground I get 12 volts. Could I possibly have an open ground or wire broken somewhere in trunk harness?

I would like to see a follow up of this. Since I had the Kenwood installed I have had weak AM reception. Today I noticed the FM was switching between HD and analog, so if there is a powered amp that has no power it might explain it.

I've even had trouble getting WBAP in places. I have picked up BAP on a spectrun analyzer. They have one of the most powerful transmitters in the DFW area. I think it is 1.21 gigawatts, so I could even travel in time.

On the '04 (right) radio antenna module, the antenna enable signal is on Pin 1 of Connector C2 (red wire). 12vdc to ground is good. Pin 2 (Brown wire) is the composite FM signal; measured to ground, it should be 4-5 vdc, with an FM signal present. The coax carries the right radio antenna FM signal from the antenna module to the radio. Someone with an '06 shop manual can verify the pinouts/wire colors for you to see if they match.

. . . Short pause, as Mr. Rogers takes my beer and keyboard away simultaneously . . . .

"Let's talk about some nice things today. . . I like FM. Can you say that, . . . FM? Good. I knew you could." :yesnod

Here's how XLR FM works (your milage may vary depending on the year of the XLR you enjoy):

The Diversity Antenna consists of two seperate antennas (elements) bonded to the ground plane on the underside of the rear decklid. The antennas are made of 20 gage, twisted pair stranded wire. A left and right antenna module condition the AM and FM signals. The primary antenna, bonded to the right side of the antenna plane receives both AM & FM signals and routes them to the right side module. The left side module receives only FM signals.

When the radio is energized, it sends an antenna enable signal (power) to the right module. When the AM or FM band is selected on the radio, the right module routes the antenna signals (from the left and right elements) to the radio.

When the FM band is selected, the FM composite signal is sent to the antenna module. Modulated on this signal is the strength of the signal going to the radio. The antenna module uses this signal to switch back and forth to each antenna element, mixing the received inputs to create a stronger signal to send back to the radio. A dual-channel o-scope could be used to measure the phase and amplitude of the FM signals as outputs of each element. You may have a faulty antenna module, which would explain why the signal is fading in and out.

An aftermarket radio receiver may not be communicating/powering with these modules, resulting in less than optimal reception. Connecting to the existing coax input would not necessarily mean the primary module is being powered up. This isn't a passive antenna. It's called an ARS (Active Reception System).

The Tech 2 will display the received signal's strength, as an aid to troubleshooting. Very cool.

Tomorrow night: Nuclear Fusion for Dummies!

CC :cheers :seeya

An aftermarket radio receiver may not be communicating/powering with these modules, resulting in less than optimal reception. Connecting to the existing coax input would not necessarily mean the primary module is being powered up. This isn't a passive antenna. It's called an ARS (Active Reception System).



Tomorrow night: Nuclear Fusion for Dummies!

CC :cheers :seeya

This is what I was wondering about. If the power is off I would expect a much lower signal, but probably enough to make the system work pretty well in a strong market. I will have the shop check to see if they have power to the module. If not they will know next time and make sure. They seem to really be interested in customer satisfaction, unlike some of the chains that I talked to before.

And I guess the question is whether I need to worry as much about the second line as I do about if it has power.

You don't need to worry about explaining Fusion. I sold the DeLorean to Doc Brown and he takes care of that for me now.

I guess I will try to locate a new module as everything else looks good. If that doesn't work, I'm going to get a windscreen and mount a 'tune trapper' hidden antenna on the top of it. I heard that they work pretty good in street rods and other projects where you don't want an exposed antenna.

I had the exact same problem and somewhere on this site I read that an owner of an '06 corvette had the same problem and for some odd reason he found that if he switched to AM and then right back to FM quickly the static on the FM was gone. I thought, "NO WAY," but easy enough to try and at no cost. IT WORKS every time for my '06 XLR! I was ecstatic. Give it a try.

Sounds crazy...but try this...I read it on a corvette forum and it works on my 06 XLR...when you start the car, hit the AM button then back to the FM...clears mine up every time!

I will try this trick this weekend and let you know.

I can't believe it but this trick does work. I can be parked with a local station on with real bad reception, go to AM and back to FM, and reception is perfect. Thanks Lucy! I was getting tired of cd's. I guess it is just a flawed radio.

mikeofalltrades,

I'm glad the trick worked for you too. I was amazed...I haven't been on for awhile, but we're getting ready to put our car away for the winter and need to find out if we need to do anything for preparation, or maintaining.

Lucy