For the last 7 years I've had terrible AM reception. The locals blamed it on the limestone ridge between me in Fremantle and the transmitters, but reception was pretty woeful anywhere,
We went to the caravan & camping show a few weeks back, and got talking to a Bunbury based car stereo shop (Soundwave) about AM reception. They said they fix quite a few every year, so given my daughter and grandies live near Margaret River, I said I'd call in next trip down south. And I did.
Would you believe that despite several unsatisfactory trips to my local shop (on reflection, can't justify their lack of testing) and the 7 years of angst, 2 hours and $180 spent after arriving in Bunbury, I had a new lead and aerial - which fixed the problem. My local shop had tried running additional earth leads etc, to no avail.

It appears that when the local aerial makers moved production to China, there was a "within aerial" connection problem near the base which was not discovered for some time. So, get a proper check - mine was connecting the new lead and aerial outside of the car to confirm a proper connection, then fitting through the engine bay to the bull bar mounted aerial. So, this problem could apply to anyone.

Now I can listen to AM in the metro area - not as clear as FM of course, but I prefer 1080 6IX format/music.
Will be a trip coming up in the next few weeks to check out country ABC, but I'm pretty sure all will be well!!!!