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Re: '90 Coupe Quattro stereo

In message <941210190133_76030.63_HHB25-1@CompuServe.COM> "Timothy P. Gallagher" writes:
> I experience engine noise through my 1990 Audi Coupe Quattro factory-installed
> AM/FM/cassette stereo;

My first question would be: engine noise or alternator noise?  Sharp rattling 
spikes or an intrusive whine?  What does the noise sound like?

Audi in Germany used to publish a very helpful and very simple little leaflet 
on "Funkentstoerung in Audi Fahrzeuge" or some such.  There was a companion 
leaflet entitled "Kurzwellenempfang in Audi Fahrzeuge".  They were very 
good. I've forgotten the exact check order, but it was basically ignition 
suppression, alternator suppression, radio power lead choke, engine bay 
grounding straps, motor hood grounding strap (extra) and then various small and 
cheap suppression capacitors.
Unusually for Audi documents, they suggested you could usually solve the 
problem for peanuts.

But they both made the point that most users will find Audis perfectly
suppressed - adequate even for sensitive amateur radio equipment.  I use an
AR1500 Wide Band Monitor in my ur-quattro and 12 year old 80CD (4000 5-cyl)
and NEVER pick up a signal from the car.  It shouldn't happen.

Your comment about "wiring filter" raises a minor concern.  This sounds like
a choke in-line in the radio's power lead.  It's a band-aid to circumvent a
problem - and in my (personal) experience it's never completely satisfactory.
It's much better to identify the source of the signal - Audis are generally
very well suppressed and most radios won't pick up a glimmer of a problem.
Be prepared to get ugly and insist that the cause is fixed, not the
symptom.  This may cause problems at your "specialist" - he'll be geared
up to add bits and fix symptoms, not replace potentially defective Audi parts.

But there's almost nothing worse that a sound that you KNOW you can hear, and
everyone else thinks is "tolerable".

Phil Payne
Sievers Consulting UK
Vice Chair, UK Computer Measurement Group
+44 385 302803 Fido 2:2503/415  CIS 100012,1660