# Swapping head units... Diversity antenna?



## Jatkinso (May 29, 2004)

I have a 1999 328i with the business cassette/CD changer head unit. The head unit died, so I am swapping it out with a Business CD/CD changer head unit from a 2003 330i. One issue, though. My car has the "diversity" radio with two antennas, the new head unit only has one - when I plug the antenna in I get no radio reception - just static.

Any ideas on how I can get the radio to work?


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## mh328i (Apr 12, 2004)

The dealer makes a $20 adaptor that will allow you to plug in the proper of the two cables into the radio's antenna input. This alone does work, however the right way to fix your problem is to order the new antenna amplifier as well. This makes for a total of about $230. If you go to the dealer just ask them to look up the service memo for replacing a CD43 radio with a CD53(which is what you did).


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## pjee (Nov 3, 2005)

Hello

Is There No Way Of Making A Modification To The Antenna Amplifier Or Cabling?? I Did Similar Action And Also Poor Reception. How Do I Link The 2 Signal Cables To 1?


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## tom @ eas (May 5, 2004)

Jatkinso said:


> I have a 1999 328i with the business cassette/CD changer head unit. The head unit died, so I am swapping it out with a Business CD/CD changer head unit from a 2003 330i. One issue, though. My car has the "diversity" radio with two antennas, the new head unit only has one - when I plug the antenna in I get no radio reception - just static.
> 
> Any ideas on how I can get the radio to work?


You need this adapter:

*BMW Business CD Radio Antenna Adapter*
http://www.europeanautosource.com/product_info.php?cPath=67_69_140_143&products_id=292

This will get your reception back on track.


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## KY528I (Dec 9, 2006)

I too had a diversity radio, and I used the kit provide to me by EAS and it works just fine


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## Smoki (Oct 2, 2007)

*swaping tape deck for business cd.*

hey,

i'm having the same problem, i swapped the tape deck, with a 2005 bmw business cd. 
right now my antenna is not connected anywhere, just the dps is hooked up. i was looking for adapters online, but it's not making much sense to me right now.

the one provided by the EAS, if i understand correctly will allow me to plug in the antenna, but than my DSP will not be hooked up.

i'm stuck, any suggestions?

thanks,
smoki


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## tom @ eas (May 5, 2004)

Smoki said:


> hey,
> 
> i'm having the same problem, i swapped the tape deck, with a 2005 bmw business cd.
> right now my antenna is not connected anywhere, just the dps is hooked up. i was looking for adapters online, but it's not making much sense to me right now.
> ...


You will need only the larger of the 2 connectors, this adapter is required:

*BMW Business CD Radio Antenna Adapter*
http://www.europeanautosource.com/product_info.php?products_id=292


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## rootehound (Nov 4, 2006)

Does anyone know if there is an adapter for an E36 - The EAS one seems to be only for later cars.

Thanks!


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## Blak Blur (Aug 6, 2006)

Is an adapter needed when going from a C33 to a CD43?


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## frankc (Jun 20, 2011)

Hi. I appreciate that this thread is old, but you guys seem to know what you are talking about.

I have just fitted a new Headunit, a Hualingan. My old radio had two aerial type leads coming out of the back of it. I bought an adaptor and fitted the larger aerial into my new unit. That leaves the Diversity aerial unconnected. So can you tell me please

1. Should I try and connect this Diversity to the new unit somehow?
2. If it is connected what benifits will I get from it?
3. If I should connect it what should I use?
4. My Hualingan RDS/AF does not work on my new unit could this be the cause?

Thanks guys !


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## frankc (Jun 20, 2011)

Nothing?? No ideas ??


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## DennisCooper! (Jan 29, 2011)

Hi frank!

You must be thinking I'm stalking you ! I'm not! really I'm not!

I think you'll find this audio section on this forum not very busy at all, also, recently there's not been much discussed in terms of more in depth audio ideas and issues etc so knowledge is sparse at best.

I'm afraid you're going to have to trawl more websites, keep knocking on the door of the seller and the manufacturer for any help and I suspect, keep having to tear your hair out looking to finally have your unit working...

Diversity antenna are where two (or more) actual antenna are used to pick up radio frequencies. They are then connected to a box which can analyse the signals and combine or use the one with the strongest signal to be passed to the audio head unit/tuner module etc. As far as i'm aware in our BMW's the oem antenna and amplifier unit does this function and a single lead is output which connects to the back of the oem head unit, I've not heard of a head unit that goes in the dash area of our cars which has two aerial inputs. 

The RDS/AF function is of course dependant on a good quality signal arriving - thats the same on any head unit with a tuner module. The oem Amplifier unit in our cars does need a 12V supply in order to process the signals it recieves, previously with the oem unit, there was a 12V supply fed back from it to do this. Aftermarket obviously doesn't have that. I have the same issue with lousy FM reception with my Alpine due to this. My solution is that I'll probably just find a 12V switched source to connect to the oem amplifier, and longer term, to mount an external aftermarket quality antenna that's capable of FM/AM/DAB/TV and GPS signals and use that. 

Cheers, Dennis!


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