Press rear windscreen heating spoils radio reception

notorious · #1 31st January 2011, 11:53 PM

Another question:

When I engage rear windscreen heating by pressing the button on climate I hear hissing sound from radio. Seems like reception quality becomes poor during heating.

I know about 4 antennas in rear windscreen and diversity switcher. Is something wrong with them or is it normal to lose some reception quality during heating?

If it's abnormal, where I should look first? Diversity switcher?

Thanks.

IT · #2 4th February 2011, 08:06 AM

In short, I dont know, I rarely drive with the radio on, and I dont have a D2 now to compare.

Audi were pretty thorough with their heated screen implementaton:

In 1997 when the S8 first came out with Navigation, they fitted a special circuit to the rear parcel shelf that made sure the heated screen and the electronic compass for the GPS were never on at the same time to save the Navigation getting screwed up, so seems unlikely they would overlook radio interference.

The diversity was only fitted to cars with Sat nav after 1998 or to every car after late 2000 as prior to that cars had a rear wing mounted electric aerial.

I guess you'll have to hope a D2 forum member can test for you and see what they get, although I'm not sure whats likely to be at fault if theirs works fine...

jayzee · #3 4th February 2011, 08:29 AM

Check the connections to the rear screen element. If they are in any way corroded you will get a high resistance on the circuit, and noise as a result.

Just a thought.

notorious · #4 4th February 2011, 05:56 PM

Thanks Ian and Thanks Jayzee.

I hope others will share with me their "heating" experience while redio is on

Condor · #5 4th February 2011, 08:16 PM

My D2 FL S8 has done that for years, well ever since I've owned it. I switch the radio off if I need to use the rear screen heater. It doesn't interfere with anything else - CDs etc. Never need the rear screen heater on long so it doesn't really bother me.

notorious · #6 5th February 2011, 08:52 AM

Thanks Condor,

I'm not alone

B@fink · #7 5th February 2011, 02:07 PM

mine is fine, radio isn't bothered by HRW operation at all so i suspect hissing is not normal....... My ariel is wing mounted as i'm a 97/98 model and that's with the mast at half height (won't go higher, stone pinged off it and dented a section stopping full extention) which has always given perfect reception

Mr K · #8 6th February 2011, 11:53 AM

mine seems OK?

This might help:

http://www.audi-sport.net/vb/satelli...n-options.html

The first bit says how to check your antenna's working ok.

might be worth seeing if it changes when the rear windows turned on and off.

notorious · #9 6th February 2011, 07:28 PM

Thanks Mr K,

I'll try that. Though I upgraded to RNS-E recently I'll pop my RNS-D back and will play with menus.

...not completely sure though what all those numbers mean

But we'll see

Searched other forums. People with the same problem say that changing rear window (!) cured the problem.

http://audiforums.com/forum/showthread.php?t=88595
http://www.audi-sport.net/vb/new-a3-...reception.html
http://forum.e46fanatics.com/showthread.php?t=46705
http://forums.mercedesclub.org.uk/ar...p/t-14790.html

I don't really understand as to why it's the window itself -- when demister if off the FM reception is great. I remember I've checked my rear window when it was cold and all heating "threads" were actually working, so there's no apparent visible damage.

Any more thoughts?

P.S.

I wonder why car industry integrate aerials to windscreen -- because it's cheaper or because reception is better vs traditional rod aerial?

Frankly, I don't want to change rear windscreen if it actually causes the problem. I have car with rod type of aerial on the rear fender and it has that little box (amplifier?) under the aerial and it has unused "Radio" socket:

I'm thinking to connect that socket directly with radio unit, bypassing the windscreen system, but not sure about reception quality. Could anyone comment about that "amplifier" and technical feasibility of such "upgrade"?

Anyway, there are 3 sockets on the little box:

1. Funk, GSM 900-1800, connected with another "signal amplifier" and then with GSM module.
2. RC, 433Mhz. Have no idea what it is.
3. FM Radio and +12 DC.

At the moment only socket number one is actually used in my car.

Could anyone explain please what's is the socket number 2 -- "RC 433Mhz" ? Remote Control I suspect...

Questions, Questions, Questions...

christhompson · #10 8th February 2011, 04:25 PM

My D2 has a half height antennae mast on the LH rear wing. It has been replaced twice by me and has no amplifier. In the UK all BBC stations work well on RDS but in France we regularly pass from weak signal to weak signal and needs new tuning. The exception is French motorway radio which is fine everywhere. Personally I'd prefer a rear screen aerial as there would then be no chance of knocking it off on a tree as the barge needs such a large space I'm often backing into a small space under a tree