radio reception bad when antenna plugged all the way in

[ccrs8]

I have an aftermarket stereo for my Subaru Impreza. I noticed that my wife's car can maintain crystal clear reception on our favorite NPR station miles and miles further than my car can even get static-y reception. I get static even when we are very close to the station broadcast location as well.

I took out the after-market head unit to play with the wiring and everything looked good. Then I took out the antenna wire and put it back in slowly. I noticed that when I gently hold the male end of the antenna wire (the part attached to the car) just at the entrance point to the female plug on the head unit, the reception is crystal clear, just like in my wife's car. However, once I push the plug in further and in all the way, the great reception is gone and it is back to terrible reception for all but the absolute closest of stations (and again, even that has static).

Do you think this is something wrong with my radio? The antenna plug of my car?

Thanks for any help!

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[keep_hope_alive Premium Member]

do you have a Metra or Scosche antenna adapter for the car?

what year is the car?

 

[ccrs8]

Yesterday I went to Best Buy and got a 12" Metra antenna extension cable to see if putting that between the antenna cable coming from the car and the HU would help (I had read on a Subaru forum that that fixed their problem), but it did not help. The same thing happened - when I put the male plug at the opening of the antenna port on the HU I got clear reception, but pushing the plug all the way in made the reception go bad.

The car is a 2006 Impreza Sport Wagon (regular, not a WRX). It has no enhanced audio components - everything stock, no subwoofer. It has an embedded window antenna that requires the power antenna to be hooked up, but I made sure that I did that (I learned that mistake from an earlier after-market radio I installed that originally got NO radio as opposed to the weak radio signal I'm getting now).

The radio I'm having trouble with is a JVC KD-R800. As a sanity check, last night I reverted back to the stock radio and everything is working great - crystal clear reception miles away just like my wife's car.

 

[keep_hope_alive Premium Member]

Sounds like an antenna grounding issue.

One quick and dirty fix would be to wrap electrical tape around the outer shield connection (not the center pin). That would insulate the shield from the head unit, which seems to be when you have the issue. When the antenna shield comes in contact with the head unit shield connection. This is typically a simple grounded connection, but you have something else going on.

Also, try grounding the head unit to chassis.

I would want to measure voltage and continuity and resistance associted with the antenna. I would get everything operational but leave access to the antenna wire. Then, with the antenna disconnected, measure DC Voltage on the center pin referenced to chassis, shield reference to chassis, and center pin referenced to shield. With everything disconnected and off, I would measure resistance between pin and shield, between pin and chassis, and between shield and chassis.

 

[bjude1 10+ year member]

I would just clean the grounding of the antenna. "The Base of the antenna"

 

[ccrs8]

Thanks for the responses! I think I'll have time today to take a look at the grounding issue.

If it is a grounding issue, could this be why when I have my smartphone plugged in to the cigarette lighter for charging and try to listen to streaming audio from it through my car speakers via the aux-in port of the radio, I get a lot of distortion and hissing? To get clear sound I either have to unplug the phone from the cigarette lighter (and drain the battery while streaming the audio) or use an aux-in cable that has a noise filter on it (that's what I do). When I researched that issue when I first got the radio, the consensus of those on the internet was that I was experiencing a "ground loop" issue.

 

[keep_hope_alive Premium Member]

likely that grounding noise is to blame.

 

[ccrs8]

Thanks for the help everyone. I fixed the grounding issue and now I have perfectly working radio and no longer have to use an aux-in cable with a bulky noise filter in order to listen to music streaming from my phone.

 

[tytler32u 10+ year member]

What did you do exactly?

 

[ccrs8]

Initially I removed the ground wire from the harness and attached it directly to the chassis, but last night I received a new harness from crutchfield and re-did all the wiring, and it ended up working. Given that I also had to bypass the old harness to get the dimmer to work but the dimmer works perfectly with the new harness, I'm assuming the harness I was using was not the correct one.

 

[keep_hope_alive Premium Member]

Wow. Not sure I would have guessed you had the wrong harness... Good job solving the problem. Grounding is so important to get right.