Hi, I have a CarPC installed (but that is irrelevant, really) in my 2003 G35 w/Bose along with a Visteon HD Zoom for HD Radio. I have the factory antenna wired to the antenna-in on the HD Zoom, and the 12v constant, switched, and ground wired up to the device as well. It works - sort of.

When it is turned on, I do get static and NPR comes in but very poorly. No other station comes in at all. When using the seek feature, it only stops at the NPR station (85.5 FM). When I tune specifically to a station I know exists (93.9) I can barely make out music but it is 95% static.

I read that the G35 has a powered antenna so I went ahead and hooked up a 12v accessory line to the antenna power wire (I think it is blue) in one of the wire harnesses from the old head unit. I could look up the exact wire if needed. This did not fix anything.

I'm looking for pointers on how to troubleshoot this poor signal quality. How can I confirm if the antenna is being powered? I took off the rear trim panel on the driver's side of the car, against the read windshield and all I see there is a single wire running to the antenna in the glass. It must be powered/amplified from elsewhere in the car. Where would that be?

I've had this issue for probably 2 years now and am just getting around to wanting to fix it. If anyone can help, I'd really appreciate it!

Thanks!

 

The antenna amp is powered directly from the one power wire going to it. It is not a power signal wire.



Check for power at the actual amplifier on the rear pillar.

 

Thanks, that was helpful. I took another look at the 12v connection at the power outlet in the center console between the front seats. I used a voltmeter to check for continuity and found that the power was not making it into the wire harness. So I re-did the connection and I traced the voltage all the way back at the antenna amp - good!

I also put electrical wire around the antenna cable where it connects to the antenna extension cable - in case it was rubbing against some metal. That seemed to make a difference.

So I think the installation is now correct and I can get HD radio on 85.5 NPR. But I still feel like other stations are weak. In fact, I unplugged the amp altogether and there was no signal difference - it may have been slightly worse, actually, when it was plugged in. Unplugging the antenna wire(s) from where they clip to the rear windshield also produces no gain/loss in antenna signal.

I think I'm close, anything else I can do to figure out how to get a stronger signal? I'm getting 12v all the way back to the antenna amp now.

 

The antenna amp may have been damaged if it was wired up incorrectly.

 

This afternoon, the signal is back to crap! I will pull the trim off again and ensure that the 12v is making its way back there still - not sure why it wouldn't be, though...

 

Are you using the radio's accessory wire? Aftermarket radios do not send enough current along that wire to power the amp. The cigarette lighter power wire or the radio's own switched +12v power wire are much better.

 

I tapped into the accessory plug/cigarette lighter. I have 12v all the way back at the amp.

 

Are you running anything else off that circuit? If not, I'm inclined to believe the antenna amp itself is bad, or your HD receiver is no good.

 

The screen is powered from whatever the factory head unit would have been powered from. Everything else runs direct from the battery.

 

I have the same problem with Infiniti OEM antenna and Visteon HD Zoom HD Radio. I moved Visteon temporarily in the trunk and run antenna wire from HU to the trunk thru center of cabin. AM/FM signal is almost nill. I wonder if splicing antenna wires close to antenna amp. would make any difference?

jsm11482, have you find any solution?

 

No solution, really. I had it working, or at least the signal was somewhat better, at one point but that only lasted like a day. Not sure what else to do! Please let me know if you come up with anything and I'll do the same.