BMW 3-Series (E90 E92) Forum - View Single Post - Xtrons headunit

BeamerNub · 08-23-2018, 10:45 AM

blueh88

It's taken long enough..... but I have some answers...... Yes, you can tap the factory antenna, and yes, it works...... and yes, you can modify a crappy £10 diversity module from eBay, to work.

I didn't buy a DAB diversity module in the end, however I finally got chance to dismantle the one I bought for a tenner on eBay. Pretty much all of the gubbings for the DAB appear to be already there and according to the BMW dealer I spoke too, the same rear glass was used on every BMW E90, including those with and without DAB.

So, all you really need to do is just solder a proper connector on:
https://www.ebay.co.uk/itm/UK-Seller...8AAOSwjDZYlOuZ

Instead of waiting around, I had an old universal 5cm fakra to fakra connector that wasn't much use to me anymore. I cut one end off and soldered the live wire to the centre pad and the earth to one of the 4 surrounding pads. This was just for testing.

Very sorry to those who like good soldering. I like good soldering too, but I was using my brand new iron and it came with a pack of 100% lead-free solder. Have any of you ever used it? Don't. It's awful. It doesn't flow at all. You can use as much flux as you want, it just doesn't flow at all. It goes into big lumps like that. Terrible stuff. Throw it in the bin and buy some nice lead solder.

I didn't have a long enough cable to test with the USB dongle in the front, so I grabbed an old Kenwood DAB radio that was in my Mazda, hooked it up to a car battery charger used that.

Voila, it works......

So, having come this far, I felt it was worth a punt.....

Grabbed one of these:
https://www.ebay.co.uk/itm/5M-Metre-...IAAOSwICZbc~6S
and
https://www.ebay.co.uk/itm/CEN-SMA-M...AAAOSwSUdbbq7q

(There's a very good reason I didn't buy a 5M Fakra to SMA)

Now unfortunately, I've lost all my photos from here out, but from memory....

Obviously solder the new fakra PCB connector onto the board. I would buy a yellow one, it's more OEM then. You'll need to modifying the plastic casing as it's all blocked off. I just took a dremel to it. Took about 5 minutes to lob off enough to get the case back on and tbh, you'd think it was OEM from the outside if you're careful(ish).

It's held to the car by the two black torx in the middle. Remove the old one carefully. The ribbon cable to the rear cluster is very thin. Screw your new one in. It might be a good time to connect the power connector as it can be a pain to get back in when on the car.

Now, wire routing. I couldn't route the cable through the roof. Everytime I tried, using a coat hanger or something similar, I eventually hit something. I didn't even get very far along tbh, at least I don't think I did.

Your best option without removing the whole roof lining, is to run the wire to the left or right and down the C-pillar, then run it like a normal cable along the floor. I had already run the cabling for the reversing camera down the right hand side, so I decided to go to the left. It's easy. You don't even need a coat hanger, just lever the roof lining at the back slightly with your finger and run the wire along, boom, it'll run straight down the C-pillar. Make sure it is not interfering with the airbag, can't really stress that enough.

Once you've run it down there, you can angle the rear seat cushion forward, run it down the side so it's properly obscured to the floor where the other OEM wiring is and then route it under the 'scuttle panels'(? Not sure what you call them) that run along the floor. All very simple. Took about 20-30 minutes at most. Once you're at the front, there's some trim you have to drop down under the fuse box. I had already done that once before to put the yellow live wire in, so no issue there. Run it up behind the head unit and boom, put in the converter to SMA which is what all those USB dongles work.

There's a fairly generous amount of slack unsurprisingly, so I bunched it up under the fuse box. There's a few places you can cable tie it too. Leave a bit so the wire is nice and floppy and not straining. I notice the OEM antenna is very short. You could try a 3m cable, but I'm not sure if it would be long enough. Probably, but better being safe than sorry and the 5m cable was only a pound more anyway!!

Connect it to the head unit. Cross your fingers and hope it works. Boom.... it does.

The signal is pretty solid. 7.5/10 I would say. I've driven with it like this for a few weeks though and I don't think I'll be going back to the windscreen antenna as it's definitely improved and it's much more seamless. I will probably leave the windscreen antenna just in case, but if I was to do it on another E90, I wouldn't bother with the windscreen one.

I will be honest and say now that it's not as good as my sisters F30 reception wise. There are maybe one or two consistent dead spots on my drive to work where you get that nasty distortion and drop outs (for a second or two) and my sisters doesn't seem to do it as much or at all, but there's potentially a few reasons for that:

1. The DAB interface is a cheap generic piece of kit from China, that wasn't even designed for cars, not a heavily tested and abused piece of kit designed by a big car manufacturer. It's possible that there are edge cases in signal distortion that it can't handle.

2. Although DAB is now considered a fairly mature technology, my E90 was registered September 1st 2006, so it's hardly new. I also suspect still has the original rear windscreen. DAB was a reasonably new technology in 2006, and DAB+ didn't even exist back then! Most car manufacturers didn't adopt DAB technology until DAB+ because the original DAB was so ropey. It's fair to say BMW were working with a fairly limited set of parameters. I suspect they've worked on fine tuning the antenna itself that is built within the windscreen and it is much better. I think they can be forgiven though. Also, age will have no doubt played a part. The metal elements degrade with time, they certainly did on my VW.

3. I've missed something on the diversity module or made a mistake in my install. Although it works, it's entirely possible there's a component I missed on the diversity module or something. The 5m wire is too long? Etc etc etc.

Anyway, I would still say it's a success and wouldn't hesitate to recommend this as a cheap OEM way to take advantage of DAB

Took a while, but we got there

08-23-2018, 10:45 AM	#49
BeamerNub Private 12 Rep 65 Posts Drives: 3 series Join Date: Jun 2018 Location: England iTrader: (0)	blueh88 It's taken long enough..... but I have some answers...... Yes, you can tap the factory antenna, and yes, it works...... and yes, you can modify a crappy £10 diversity module from eBay, to work. I didn't buy a DAB diversity module in the end, however I finally got chance to dismantle the one I bought for a tenner on eBay. Pretty much all of the gubbings for the DAB appear to be already there and according to the BMW dealer I spoke too, the same rear glass was used on every BMW E90, including those with and without DAB. So, all you really need to do is just solder a proper connector on: https://www.ebay.co.uk/itm/UK-Seller...8AAOSwjDZYlOuZ Instead of waiting around, I had an old universal 5cm fakra to fakra connector that wasn't much use to me anymore. I cut one end off and soldered the live wire to the centre pad and the earth to one of the 4 surrounding pads. This was just for testing. Very sorry to those who like good soldering. I like good soldering too, but I was using my brand new iron and it came with a pack of 100% lead-free solder. Have any of you ever used it? Don't. It's awful. It doesn't flow at all. You can use as much flux as you want, it just doesn't flow at all. It goes into big lumps like that. Terrible stuff. Throw it in the bin and buy some nice lead solder. I didn't have a long enough cable to test with the USB dongle in the front, so I grabbed an old Kenwood DAB radio that was in my Mazda, hooked it up to a car battery charger used that. Voila, it works...... So, having come this far, I felt it was worth a punt..... Grabbed one of these: https://www.ebay.co.uk/itm/5M-Metre-...IAAOSwICZbc~6S and https://www.ebay.co.uk/itm/CEN-SMA-M...AAAOSwSUdbbq7q (*There's a very good reason I didn't buy a 5M Fakra to SMA) Now unfortunately, I've lost all my photos from here out, but from memory.... Obviously solder the new fakra PCB connector onto the board. I would buy a yellow one, it's more OEM then. You'll need to modifying the plastic casing as it's all blocked off. I just took a dremel to it. Took about 5 minutes to lob off enough to get the case back on and tbh, you'd think it was OEM from the outside if you're careful(ish). It's held to the car by the two black torx in the middle. Remove the old one carefully. The ribbon cable to the rear cluster is very thin. Screw your new one in. It might be a good time to connect the power connector as it can be a pain to get back in when on the car. Now, wire routing. I couldn't route the cable through the roof. Everytime I tried, using a coat hanger or something similar, I eventually hit something. I didn't even get very far along tbh, at least I don't think I did. Your best option without removing the whole roof lining, is to run the wire to the left or right and down the C-pillar, then run it like a normal cable along the floor. I had already run the cabling for the reversing camera down the right hand side, so I decided to go to the left. It's easy. You don't even need a coat hanger, just lever the roof lining at the back slightly with your finger and run the wire along, boom, it'll run straight down the C-pillar. Make sure it is not interfering with the airbag, can't really stress that enough. Once you've run it down there, you can angle the rear seat cushion forward, run it down the side so it's properly obscured to the floor where the other OEM wiring is and then route it under the 'scuttle panels'(? Not sure what you call them) that run along the floor. All very simple. Took about 20-30 minutes at most. Once you're at the front, there's some trim you have to drop down under the fuse box. I had already done that once before to put the yellow live wire in, so no issue there. Run it up behind the head unit and boom, put in the converter to SMA which is what all those USB dongles work. There's a fairly generous amount of slack unsurprisingly, so I bunched it up under the fuse box. There's a few places you can cable tie it too. Leave a bit so the wire is nice and floppy and not straining. I notice the OEM antenna is very short. You could try a 3m cable, but I'm not sure if it would be long enough. Probably, but better being safe than sorry and the 5m cable was only a pound more anyway!! Connect it to the head unit. Cross your fingers and hope it works. Boom.... it does. The signal is pretty solid. 7.5/10 I would say. I've driven with it like this for a few weeks though and I don't think I'll be going back to the windscreen antenna as it's definitely improved and it's much more seamless. I will probably leave the windscreen antenna just in case, but if I was to do it on another E90, I wouldn't bother with the windscreen one. I will be honest and say now that it's not as good as my sisters F30 reception wise. There are maybe one or two consistent dead spots on my drive to work where you get that nasty distortion and drop outs (for a second or two) and my sisters doesn't seem to do it as much or at all, but there's potentially a few reasons for that: 1. The DAB interface is a cheap generic piece of kit from China, that wasn't even designed for cars, not a heavily tested and abused piece of kit designed by a big car manufacturer. It's possible that there are edge cases in signal distortion that it can't handle. 2. Although DAB is now considered a fairly mature technology, my E90 was registered September 1st 2006, so it's hardly new. I also suspect still has the original rear windscreen. DAB was a reasonably new technology in 2006, and DAB+ didn't even exist back then! Most car manufacturers didn't adopt DAB technology until DAB+ because the original DAB was so ropey. It's fair to say BMW were working with a fairly limited set of parameters. I suspect they've worked on fine tuning the antenna itself that is built within the windscreen and it is much better. I think they can be forgiven though. Also, age will have no doubt played a part. The metal elements degrade with time, they certainly did on my VW. 3. I've missed something on the diversity module or made a mistake in my install. Although it works, it's entirely possible there's a component I missed on the diversity module or something. The 5m wire is too long? Etc etc etc. Anyway, I would still say it's a success and wouldn't hesitate to recommend this as a cheap OEM way to take advantage of DAB Took a while, but we got there Last edited by BeamerNub; 08-23-2018 at 10:55 AM..*
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