I've found that it is possible to use the existing rear screen antenna to feed a DAB / FM radio signal to a head unit. I disconnected all of the wiring from the existing antenna amplifier (apart from the ground feed to and from the heated rear screen of course). The 12v feed from the head unit was used to power the a new amplifier (A4721.01 about £50 from www.co-star.co.uk). I also purchsed some FAKRA Female Water Blue connectors from the same place so that the input and output signals could be connected to the amplifier. I connected both rear screen antenna wires together before feeding them into the amplifier. I used the existing FM/AM cable and I already had another SMB co-ax cable in place for the DAB signal from an earlier failed attempt using an E-bay amplifier that proved to be rubbish! My head unit is a Pure Highway H260DBi and I'm getting 4 out of 4 bars DAB signal strength on many stations
Bog standard!
Re: DAB radio signal using the rear screen antennas
[Re: MIB]
#1637356 06/12/201913:3506/12/201913:35
I can't quite work out the wiring arrangement that is referred to however, perhaps MIB can give us a nice diagram? In particular, is there a DAB aerial anywhere? I was thinking of something like this https://www.co-star.co.uk/3839/dab-glass-mount-antenna-gmdab3l-5f/
1996 Portofino 20vt & 2000 Pearl White Plus 2008 Ferrari F430 & 2017 Fiat 124 Spider
Re: DAB radio signal using the rear screen antennas
[Re: MIB]
#1637986 06/01/202018:5906/01/202018:59
Part of the reason for this mod is that I didn't want to use one of those ugly stick on DAB antennas The heated screen elements are all the antennas needed. In fact DAB signals are horizontally polarised, so the rear screen antenna is ideal! The reason that an amplifier was used in the first place is to boost the FM/AM signals, which are transmitted by vertical antennas, to make up for the inherent losses when trying to receive a signal with a cross polarised receive antenna.
If I was to do this mod from scratch, I would do the following:
For the AM/FM signal output from the new amplifier to the radio Google 'Female FAKRA to Male Din 5m cable'.
For the DAB signal output from the new amplifier to the radio Google 'Female FAKRA to SMB 5m cable'.
Run these two cables from the new amplifier down the nearside of the car behind the left rear speaker, under the carpet by the passenger door and over the footwell to the radio.
Google 'Female FAKRA cable repair kit'. This is FAKRA connector to a flying coax lead. Solder the centre wire of this coax (make sure to not connect the coax outer screen to anything) to the ends of cables 2 and 3 in the attached picture. This connects together the two AM and FM antennas built into the rear screen and their received signals are now used as the input to the new radio amplifier.
I think that this is a far better way to do it than my bit of a bodge up!
Last edited by MIB; 06/01/202019:00.
Bog standard!
Re: DAB radio signal using the rear screen antennas
[Re: MIB]
#1641563 06/06/202016:5506/06/202016:55
Looks like that adapter is Fakra to SMA. The connector used on the original radio amplifier for the radio is not SMA so this is no good for you. I don't know what Fiat have used, but it doesn't look standard! As you will need to run a female Fakra to SMB cable from the new amplifier to the radio for the DAB signal, I would also buy a female Fakra to male DIN for the FM signal at the same time.
Bog standard!
Re: DAB radio signal using the rear screen antennas
[Re: MIB]
#1641626 09/06/202018:5309/06/202018:53
I've got the same Pure dab radio in mine but using a stick-on film aerial on the front screen(from halfords) on the n/s, work OK and doesn't look bad. Didn't think of using the existing
Re: DAB radio signal using the rear screen antennas
[Re: MIB]
#1641646 10/06/202015:2510/06/202015:25
In fact DAB signals are horizontally polarised, so the rear screen antenna is ideal!
The reason that an amplifier was used in the first place is to boost the FM/AM signals, which are transmitted by vertical antennas, to make up for the inherent losses when trying to receive a signal with a cross polarised receive antenna.
I'm in the process of investigating this mod, not only to dispense with the stick-on windscreen aerial but to improve reception.
Reading this very informative article posted by a retail establishment in Yorkshire it reckons that DAB transmissions are actually vertical, although if the coupe rear screen aerial does better than the adhesive one I'm fine with that! Indeed I was advised to align mine the same way after having originally located it horizontally - but tbh I didn't gain much difference.
At the outset, DAB stations were allocated a high data rate giving excellent sound quality. More recently, this bandwidth has been reduced, with the sound quality suffering accordingly. The digital radio offered on satellite transmission currently has a better quality than DAB.
So I'm wondering whether the drop-off in reception on my stick-on aerial might have something to do with that...
BumbleBee carer
Re: DAB radio signal using the rear screen antennas
[Re: Edinburgh]
#1641731 13/06/202013:4713/06/202013:47
Yes mate, that's the one, assuming the DAB input on the back of your head unit is an SMB male plug. After loads of searching, I've found this https://www.dabonwheels.co.uk/what-do-the-aerial-connectors-look-like/ It looks like the socket on the original amp in the coupe is a Hirschmann male plug, it seems to be a much less common version of the F connector with the thread on the outside rather than inside. As well as the FAKRA to SMB cable, I'll be ordering this https://www.dabonwheels.co.uk/product/dow-6-fakra-f-to-hirschmann-m/ to join the coax to the new amp/splitter. It's a bit of a punt, so fingers crossed it fits!
Re: DAB radio signal using the rear screen antennas
[Re: MIB]
#1641732 13/06/202014:0913/06/202014:09
Well I've taken the plunge and ordered the DAB lead and the amp - someone has just given me a £25 voucher for Amazon which worked out the cheapest anyway, so I'm rockin'
BumbleBee carer
Re: DAB radio signal using the rear screen antennas
[Re: Edinburgh]
#1642951 26/07/202020:0626/07/202020:06
So I'm wondering whether the drop-off in reception on my stick-on aerial might have something to do with that...
No. That doesn't affect the DAB broadcast signal strength - just the bandwidth (number of bits per second) allocated to each channel. The amount of data remains constant but it's shared between more audio channels, to the general unhappiness of listeners.
I used a dual FM/DAB (1 input 2 outputs - DAB and FM) adaptor (a few quid) to wire the standard rear screen amplified signal straight to my DAB/FM head unit and it works fantastically with both DAB and FM. The adaptor was the only additional cost. Signal strength is great!
Last edited by KevinW; 21/08/202014:53.
KevinW Milton Keynes UK
Re: DAB radio signal using the rear screen antennas
[Re: MIB]
#1673375 20/08/202407:3020/08/202407:30
Hi all (my first post on the forum! :-) . Just resurecting this old thread. I'm fitting a Sony DAB unit and was going down the route of looking at fitting a DAB amplifier next to the old FM one. I even scouted out what looked to be a great option on ebay, to get a second hand DAB amp from a Jaguar Land Rover - many of these available for £20 or less.
However I was just re-reading this thread when I picked up on KevinW saying to just get a simple cable splitter. That seems like a far easier solution so I'll try that first! Only a few quid on ebay for these. (Search for "DAB & FM / AM Car Radio Aerial Active Antenna SMB DIN Splitter Adapter Cable UK")
I'll update again once I've fitted to say how well it works (though many other reviews of this splitter suggest it should be very effective, as KevinW said too).
Last edited by C90; 20/08/202407:31.
Re: DAB radio signal using the rear screen antennas
[Re: C90]
#1673384 20/08/202413:2020/08/202413:20
I had the cable splitter without any further modifications. It hardly works. Now I have the sticker on the front screen, much more channels. An intermediate solution could be to use a splitter in combination with an amplifyer in the c-style with an improved frequence range, has not been tested yet afaik.
Last edited by jaaps2; 20/08/202413:21.
20VT, build in 1997, first used in 1998
Re: DAB radio signal using the rear screen antennas
[Re: MIB]
#1673385 20/08/202414:0020/08/202414:00
The only fool-proof solution is to have an external aerial. The splitter didn't work for me either.
If like me there was no way you were going to make holes in the bodywork then for a tenner from Halfords you can get a magnetic aerial which is efficient and strongly magnetised enough to stay put except perhaps at speed in exceptionally windy conditions.
I keep mine in the boot and stick it on the rear 3/4 panel when necessary; much further forward and it starts to pick up engine interference. The cable is long enough to route along the floor to the head unit.
BumbleBee carer
Re: DAB radio signal using the rear screen antennas
[Re: MIB]
#1673524 2 hours ago2 hours ago
I have the same solution as Simon. I put it on the boot lid whenever I drive the Coupe. ( when I remember to to put it on…..). When I do it works a treat Henk