E85 Radio Reception

[Brian H]

So I am thinking that the radio reception in my Z4 is not too good when out of town, in fact pretty dismal, a quick search brings up a guide in the resource.

https://zroadster.org/resources/how-to-locate-your-antenna-amplifier.38/

I found and downloaded a PDF detailing the layout of the aerial system, talk about complicated!

Has anyone on here had any experience of this repair?

 

[GazHyde]

Not had any issues with radio reception in mine, has it got the original aerial on it? Quite a lot of Z4's enforcing up with the short aerials fitted.

 

[Brian H]

Not had any issues with radio reception in mine, has it got the original aerial on it? Quite a lot of Z4's enforcing up with the short aerials fitted.

Thanks Gary, yes I've got the long aerial on, I'm away for a few days this week so will have a look at the connectors detailed in the link above.

 

[t-tony]

I fitted a short aerial last year Brian and haven't found it to be any problem at all.

Local FM stations are just as before, Radio 2 etc.

Tony.

 

[Brian H]

Thanks Tony, not a chance I would pick anything up with that

 

[t-tony]

I guess it's pointing to aerial amp. then Brian? I gather it's mounted in the rear bumper area.

Tony.

 

[ppavuk]

Go DAB, fm is pretty crappy in all cars, not only in z4

 

[Redline]

Go DAB, fm is pretty crappy in all cars, not only in z4

FM coverage is actually very good across most of the U.K. (Depending on the station) and is set up for working effectively with car antennas - But, and it's a big but...

Most cars are now fitted with short antennas and an amplifier. The standard Z4 antenna is like this. Fit a stubby and you need a much better rf amp on the much smaller signal that you are picking up. Any minor problems with that amp or with connectors and earthing arrangements will magnify any signal issues and reduce the radio quality.
Having said that, like any broadcast service, there isn't 100% coverage. It's targeted at population coverage, and in some locations, busy roads. The big transmitters like Sutton Coldfield have a good coverage of up to 40 miles but are still unable to reach some valleys and the shadow of large buildings. Only the hillier areas around south west Birmingham might suffer but then there seperate transmitters to cover that area.
Make sure you have RDS on as that supports transmitter switching (Traffic Anouncements are a service on RDS).

DAB is a much more complex signal and needs a good antenna and rf amp to work well. There are however many more DAB transmitters now to cover the weak signal areas. Good DAB radios also support switching to other transmitters as you move from one area to another or even switching to an equivalent FM station if a DAB one isn't available. You usually hear this because the signal timings and decode time on DAB is much longer than FM (and often different on different DAB radios - if anyone wants a masterclass on COFDM coding and decoding just ask).

Reception of most BBC FM around Balsall Common should be good. Some commercial radio stations may not be (they typically use lower transmit power than BBC).

So, if you have problems, check your cabling and amp first. If you have line of sight to Sutton Coldfield you will have a good signal. I can pick up some stations broadcast from there in Daventry in my Z4.

 

[Brian H]

Go DAB, fm is pretty crappy in all cars, not only in z4

DAB for me is a no no, I live in a location that does not get TV reception! (Don't speak to me about the licence fee!!!!!!!!) Having said that the standard FM reception around me is acceptable. My other car can receive FM no problem, sit the cars side by side , one car gets reception the other does not. I'll have a good root around this weekend.

 

[ppavuk]

FM coverage is actually very good across most of the U.K. (Depending on the station) and is set up for working effectively with car antennas - But, and it's a big but...

Most cars are now fitted with short antennas and an amplifier. The standard Z4 antenna is like this. Fit a stubby and you need a much better rf amp on the much smaller signal that you are picking up. Any minor problems with that amp or with connectors and earthing arrangements will magnify any signal issues and reduce the radio quality.
Having said that, like any broadcast service, there isn't 100% coverage. It's targeted at population coverage, and in some locations, busy roads. The big transmitters like Sutton Coldfield have a good coverage of up to 40 miles but are still unable to reach some valleys and the shadow of large buildings. Only the hillier areas around south west Birmingham might suffer but then there seperate transmitters to cover that area.
Make sure you have RDS on as that supports transmitter switching (Traffic Anouncements are a service on RDS).

DAB is a much more complex signal and needs a good antenna and rf amp to work well. There are however many more DAB transmitters now to cover the weak signal areas. Good DAB radios also support switching to other transmitters as you move from one area to another or even switching to an equivalent FM station if a DAB one isn't available. You usually hear this because the signal timings and decode time on DAB is much longer than FM (and often different on different DAB radios - if anyone wants a masterclass on COFDM coding and decoding just ask).

Reception of most BBC FM around Balsall Common should be good. Some commercial radio stations may not be (they typically use lower transmit power than BBC).

So, if you have problems, check your cabling and amp first. If you have line of sight to Sutton Coldfield you will have a good signal. I can pick up some stations broadcast from there in Daventry in my Z4.

Well, at my place fm is pretty ok, but i travel a lot, and it is pretty frustrating when fm just go noisy while driving. From experience dab, which i have on both cars, plenty more robust. I only had issues at the nort of Scotland, but nothing worked there including cellphone

 

[Redline]

DAB for me is a no no, I live in a location that does not get TV reception! (Don't speak to me about the licence fee!!!!!!!!) Having said that the standard FM reception around me is acceptable. My other car can receive FM no problem, sit the cars side by side , one car gets reception the other does not. I'll have a good root around this weekend.

Being in the broadcast industry I shouldn't be saying this, but, you're not missing much on TV


Blackhill between Glasgow and Edinburgh was for many years the only location serving both areas on DAB (although Craigkelly also serves parts of Edinburgh). There have recently been two new transmitter sites set up in Glasgow with a third to be in service soon. These are really fillers for the dead spots in the city. There is als a big tx site S or SE of Glasgow but I can't recall its name. There is DAB there too, but, sadly, the wonderful countryside up there doesn't lend itself to DAB.

As far as your cars are concerned, if you have an old working car radio and speaker (I bet you never throw anything away) try connecting that in to the antenna at the head unit if you can. If that works, it will prove the coax, amp and aerial. It's then just the radio. If it doesn't work then you need to start chasing down the cabling etc. I'd suspect the amp which I think is in the aerial itself. Not sure how the amp gets its power - it might be from the radio itself.
Am sure I've looked before but I'll see what transmitters there are around you - pick a BBC station to test on though.

 

[Redline]

Well, at my place fm is pretty ok, but i travel a lot, and it is pretty frustrating when fm just go noisy while driving. From experience dab, which i have on both cars, plenty more robust. I only had issues at the nort of Scotland, but nothing worked there including cellphone

You may find reception varies at the same location. There is about to be a massive amount of work done on tv to release radio spectrum so everyone can have 5G mobile. Much of this means changing the transmit antennas at many sites. Because when they were put in just a few years ago, this change wasn't envisaged. However, at many transmitter sites, the tv antennas are higher than the radio FM and Dab antennas. To do the work safely (if you can call working at 1000 feet off the ground in any way safe) the power has to be reduced significantly on the radio broadcasts.
Thinking about it - it has already started at Selkirk.
It isn't our fault - it's all down to O2, EE and vodafone. I expect to hear lots of complaints while we do the work though.

 

[ppavuk]

You may find reception varies at the same location. There is about to be a massive amount of work done on tv to release radio spectrum so everyone can have 5G mobile. Much of this means changing the transmit antennas at many sites. Because when they were put in just a few years ago, this change wasn't envisaged. However, at many transmitter sites, the tv antennas are higher than the radio FM and Dab antennas. To do the work safely (if you can call working at 1000 feet off the ground in any way safe) the power has to be reduced significantly on the radio broadcasts.
Thinking about it - it has already started at Selkirk.
It isn't our fault - it's all down to O2, EE and vodafone. I expect to hear lots of complaints while we do the work though.

I see you working in the industry! me not so i can only judge from user point of view

 

[Redline]

I see you working in the industry! me not so i can only judge from user point of view

The end-user point of view is really important. Despite the massive amount of monitoring of services, it's quite common for problems to occur that we don't or can't see (or hear) until someone tells us.
Many people think that radio and tv are available everywhere - sadly, that isn't possible. TV is broadcast from over 1,000 locations and radio is over 1,500. It costs hundreds of millions of pounds each year to set up and run. The electricity bill alone is £millions per month.
The TV work is going to cause real service impact to both tv and radio.

 

[Brian H]

So an update on this issue, Looked at the wiring diagram, the FM on the radio has two sources for reception FM1 & FM2, by process of elimination through the disconnection of various coaxial cables in the boot, I worked out that my car was only receiving signal via the FM2 (bumper) aerial.

E85 Aerial Wiring Diagram

Replaced part 4 below

A trawl on eBay showed a second hand unit for sale, a few days later it arrived and the radio reception is now considerably better. Happy Chap

 

[Redline]

So an update on this issue, Looked at the wiring diagram, the FM on the radio has two sources for reception FM1 & FM2, by process of elimination through the disconnection of various coaxial cables in the boot, I worked out that my car was only receiving signal via the FM2 (bumper) aerial.

E85 Aerial Wiring Diagram

Replaced part 4 below

A trawl on eBay showed a second hand unit for sale, a few days later it arrived and the radio reception is now considerably better. Happy Chap

Was the most likely cause. Pleased you got it fixed.
How much was the replacement?

 

[Brian H]

Was the most likely cause. Pleased you got it fixed.
How much was the replacement?

Not too sure why it failed TBH, quite a lot of circuitry in the small amp, I'll put it down to age. Replacement cost £20.00.

 

[Redline]

Not too sure why it failed TBH, quite a lot of circuitry in the small amp, I'll put it down to age. Replacement cost £20.00.

Most likely to be a capacitor that has dried out. It's quite exposed there taking a lot of summer heat.

 

[Craig Orton]

I bought a genuine Bmw stumpy for mine
Never had a problem seems to the same as the original one also put the same on the wifes mini that's been fine aswell

 

[Brian H]

I bought a genuine Bmw stumpy for mine
Never had a problem seems to the same as the original one also put the same on the wifes mini that's been fine aswell

My radio was fine in built up areas however I live out in the sticks where radio reception is not 100%, if I were to put on a stubby aerial I would not stand a chance of receiving a signal.