The battery died in my '98 s70 last week, and with it went the radio, since I don't have the codes for it and don't feel like hassling with the dealer. Anyway it was the perfect reason to install the pioneer that I had bought a while ago to put in her anyway.

Now my question is, it seems like the stock stereo had two antenna wires going to it. One the normal size, and the other a little smaller. The pioneer only has the one standard plug in it, so I plugged in the standard antenna wire, but my radio reception is horrible. Do I need to get an adapter of some sort for the other wire? Or what is the other wire for? I've never seen a wire like this in any radio system I've ever installed.

thanks!

 

Could the other smaller wire have been for activating the electric antenna by chance? Do you have electric antenna and is it extending all the way?

In general I am impressed with the reception i get from the stock radios in these cars. My 850 wagon has the antenna built into the rear side window and it actually gets better reception than the S70 sedan. Maybe the reception on your pioneer is just not that great...

 

I'm 100% certain this is not the wire to activate the power antenna.

From what I'm reading on other sites, it seems that on certain models Volvo put a secondary antenna in the car, which could either be tucked inside the bumper, or it uses the rear-window defroster, there is much debate on that. Anyway, the stock stereo would compare the signals from both antennas and use the stronger one. It was supposed to help in inner-city driving where multi-path error is a problem.

 

Yes. This is called a "diversity" antenna. The "normal" antenna is connected to the larger connector, and should be adequate for most stereos, though you'll never get reception as good as the stock setup. I know there used to be adapters available for the older Nissans with diversity antennas, but I tried to find one for my Volvo and couldn't. Most factory stereos these days have this sort of setup.

 

Well I'll be... I didn't believe this dual antenna stuff so I pulled the S70's SC-816 out of its hole and sure enough, there's two coax antenna cables going into it. Only mention of it I could find in the owners manual:

Diversity antenna (dual antenna system)
Certain models are equipped with the optional Diversity dual antenna system. Two antennas are connected to the radio through two separate sockets, allowing for better reception and reducing the effects of static or multipath distortion of FM reception.

What it doesn't say (and I would like to know) is where this 2nd antenna is located. Looking at the schematics I have I see only the one antenna... I am quite sure they don't use rear window heater grid for an antenna, but then...

 

I found this on the web...

 

I've noticed this decline in radio reception as well with my aftermarket stereo. I've had a JVC headunit in for several years now and am continually amazed at how terrible my radio reception is for local stations. Oh well I guess, it was an easy decision to upgrade for an iPod connection. I only listen to AM sports games on the radio anyway!