I've had this problem since i bought the head unit (back in january), and finally now decided to ask on fordmods for help.

The problem is bad radio reception, it gets worse in the higher frequency bands (100+ is awful, 90+ is almost ok, but still bad). The noise is a ticking that only occurs when the engine is on, frequency of the ticks increases as the car revs higher. With the stock ford radio, it was fine, no noise.

here are specs of everything (that i can think of) that might help:
Car: Ford Falcon Futura AU series 3
Head unit: Alpine CDA-9857
the rest of the system (although i think it's irrelevant because the noise was there before these items were installed):
amp: MRV-F545
front speakers: SPR-57LS
rear speakers: SPS-57C2
sub: SWR-1222D

About 2 weeks ago, i took the head unit back to JB-HiFi and told them what was wrong, they listened and decided to send it off to Alpine to get fixed, today, i got it back and according to Alpine "The unit was tested and nothing was wrong with the FM reception". It's back in the car and the same problems as before.

When i use the cd-player, it's crystal clear, and same with the ipod connector, no problems at all. I've run out of ideas, although im sure there are more, to what the problem is. Also, i have tried another aerial (or, the nice people at gary's car radio did) and the same interference was still there.

id be looking a gtting an inline noise filter to connect on the aerial line ... its a cheap way to rule out if its a ground loop or induced electrical noise...into the antennae circuit

Do you mean something like this? [url=http://tinyurl.com/3bfssn]
40 Amp Car Noise Filter[/url]

that's for the power line, i cant seem to find anything (in australia) on an aerial filter, what shops sell them?

Drop into a local car audio outlet and saying your getting alot of interference on the aerial line ... and mention you were told a noise filter may fix the problem ... see what they say or can offer...most guys will take a look at the car for you without charging u anything .. it aint an issue with your headunit

ok, will do tommorow

I would be looking at the antenna itself (poor reception with interference) If the inner core on the antenne cable has broken the reception will be weak especially on FM, AM will also be weak but with alot more interference. Simply take out the HU and find some wire about 2 meters long and place one end into the inner of the antenna socket and the other outside the car (do this with the engine off as there is no ground and there may be interference) if the reception is stronger replace the existing antenna.

I bought an aerial filter, installed it and no difference. Same ticking, no better no worse (that i could tell).

Joolz, i'll try that tommorow or a bit later tonight (currently raining). Thanks for your ideas.

Didnt you try connecting a whole nother aerial at an audio joint though in your first point and it made no difference?

i did, well they did, so i dont know how it changed it. According to them it made no difference. i'll try it anyway unless theres something else to try

It's probably coming from your alternator. Not anything wrong with the headunit. The alternator can create a lot of electrical noise. Could get it checked out by an auto-elec.

Just thought i'd finish this appropriately.
In an attempt to clean my spark plugs (i didn't know they were iridium, or even what that meant before now) i broke the lead on one of the leads and had to buy replacements. The leads I got apparently fixed the problem, no more noise on the radio!
I had no idea the leads couldve caused this problem, it had never occured to me (or people I spoke to as far as i remember).