Expert: Cleggsan - 9/4/2009

Question
I just had an Alpine cda-105 head unit install in 2010 Subaru Forester, am is horrible, fm is ok although some stations get interference at times. the antenna is roof
the stock radio received am ok
I took the car back to best buy installer & antenna connection was tight
thanks

Answer
I checked the specifications for this model and AM sensitivity is not given.  FM sensitivity is given and it is a good figure: 9/3 dbf.  

Generally Alpine products are good, but not as good as some others for sensitivity.  They are made and designed in Europe where sensitivity is not so critical as it is in the USA due to the fact the countries are smaller and the distances from the transmitter are closer and the terrain is not so varied as you would find in the USA.  All that being said, if the unit is working properly and the antenna is connected properly it should give you acceptable performance.

Therefore, you must have either:

-  A defective tuner in the Alpine cda-105
-  A defective antenna or connections between antenna and radio (such as a bad connecting cable)
-  A short in the cable connector - very common when installers use crimping tools that crimp too hard or a strand of the shield gets caught in the crimping process.
-  An antenna that has poor performance or is mounted improperly.

You have many things to check out and track down.  Hope this helps you find a solution.

C

PS:  Alpine units are very good for sound quality, by the way, and you should get great audio performance from this unit.