W210 AM radio reception problems

[Fais]

Hi all

My dad's 1999 E240 has problems with very poor AM radio reception, however the FM reception is cystal clear. The problem has remained even after changing the radio. Any ideas on what it could be? Problem has been there from day 1, but it has now really got on his nerves. Driving to centre of London makes it almost impossible to get any AM reception.

Can this be covered by MB Direct Warranty? We purchased the car from MB Direct in March this year - or will they stick me with a bill if they investigate only to find 'no fault'.

Thanks!

 

[lexie]

Are you sure this problem is related to the car/radio? Have you compared with another car/radio on the same locations and directions?

I ask this because AM is a by far worse technology than FM. This is also one of the main reasons why FM has been developped later on. AM is good for transmitting low-quality audio for longer distances. For AM to work good you also need the direct the antenna correctly (try it with a portable radio), which is quit difficult to do with a car. FM on the other hand can carry far better quality audio, but is not so good for transmitting over long distances. AM will also suffer a lot more from interferrences caused by industry using heavy electrical equipment etc...

In our neighbourhood for example AM reception is extremely poor and full of interferrence between 8AM and 9PM or so, but acceptable during the night. Dunno what causes this, but it starts at one specific time in the morning and stops the same way in the evening. I guess heavy machinery or transmitters must be causing this interferrence...

 

[R2D2]

My AM reception is dreadful in my W202 as well, even when I bought an Alpine head unit it remained as bad as ever.

 

[Fais]

thanks for the replies. The am reception on my SL320 is far far better than the W210 - when they are side by side in the driveway (same time of day). i am not expecting amazing reception, but something comparable to the other cars.

if this is a normal problem (differing from model to model), then i guess i can't do anything about it

Thanks

Fais

 

[DrNick]

There is at least 1 known potential cause of bad AM reception specific to the 210. IIRC this is due to the CANbus wiring loom running too close to the radio loom. I saw this on a list of known problems/advisories that I think I got info on from this site (Can't remember the web page now! - Someone else might know of it. It was a great long list, very tedious to read).

The fading due to time of day is a well known effect and is due to change in the ionisation layers in the atmosphere causing the radio waves to reflect differently at different times of the day, similiar to the 'Luxembourg effect'. Its due in the main to the frequency chosen for AM. FM is more line of sight as it uses VHF rather than MF so atmospheric reflections are not an issue.