MK6 Golf: Amplified aerials with aftermarket nav
Discussion
I've just bought and fitted an aftermarket Android head unit to my MK6 based 2009 Golf Plus. An Xtrons PS88MTVL if you are curious.
With everything installed, things seem to be mostly good, however the radio reception is considerably worse than with the original OEM radio (the car did not have nav from the factory). I am trying to get to the bottom of what the issue(s) might be and would welcome a view on my understanding and also any suggestions.
Context:
- Radio reception with the original unit was excellent (although I have only ever really listened to FM)
- The original radio had a diversity aerial (two separate aerials I think) with two FAKRA type connectors
- The new nav unit came with an aerial adapter that had an ISO type connector at one end and two FAKRA type connectors at the other. There was a junction box of some kind about half way along its length, with a blue unterminated wire coming out of it
- The FAKRA connectors on the car's loom were very slightly different to the connectors on the adapter. Essentially the connectors on the harness for the car had one of the mounting tabs slightly offset
- In order to mate the FAKRA connectors on the loom to those on the adapter, I removed one of the outer plastic connectors (thus removing the offending mounting tab) on the adapter
- I did not do anything with the blue unterminated wire.
As I understand it / what I suspect:
- The car has an inbuilt aerial amplifier that is turned on when the radio is turned on
- On the factory setup, the amplifier receives +12v and this is fed through the aerial harness (I suspect one or both of the cores) and sent to the amplifier in the car
- The new radio *may* do the same as the factory radio. If this were the case, it would also be sending 12v down the aerial connection (although I'm not sure if that is part of the ISO standard)
- The blue wire on the adapter is to inject +12v into the aerial harness for the car. This could be for all head units, or just the ones that don't supply it from the aerial connection.
- If the above were true, I need to ensure that +12v is getting in to the aerial harness. If not from the aerial connection then via the blue wire. The simplest solution I'd imagine would be to take a switched +12v from the nav unit (amp on or similar)
Am I right on all of this? Any experience?
It will be a while before I have the time to pull the car apart again (I realize a multimeter will give me at least half the answers I need) and I would like to know exactly what I need to do beforehand.
To add, there is obviously a chance that the physical aerial connection is not great. Probably a contributor, but I do think it is more than just that.
Terrible pictures of the connections below:
https://www.navi4all.com/wp-content/uploads/2019/02/PS88MTVL_8.jpg
https://www.navi4all.com/wp-content/uploads/2019/02/PS88MTVL_7.jpg
Thanks in advance...
With everything installed, things seem to be mostly good, however the radio reception is considerably worse than with the original OEM radio (the car did not have nav from the factory). I am trying to get to the bottom of what the issue(s) might be and would welcome a view on my understanding and also any suggestions.
Context:
- Radio reception with the original unit was excellent (although I have only ever really listened to FM)
- The original radio had a diversity aerial (two separate aerials I think) with two FAKRA type connectors
- The new nav unit came with an aerial adapter that had an ISO type connector at one end and two FAKRA type connectors at the other. There was a junction box of some kind about half way along its length, with a blue unterminated wire coming out of it
- The FAKRA connectors on the car's loom were very slightly different to the connectors on the adapter. Essentially the connectors on the harness for the car had one of the mounting tabs slightly offset
- In order to mate the FAKRA connectors on the loom to those on the adapter, I removed one of the outer plastic connectors (thus removing the offending mounting tab) on the adapter
- I did not do anything with the blue unterminated wire.
As I understand it / what I suspect:
- The car has an inbuilt aerial amplifier that is turned on when the radio is turned on
- On the factory setup, the amplifier receives +12v and this is fed through the aerial harness (I suspect one or both of the cores) and sent to the amplifier in the car
- The new radio *may* do the same as the factory radio. If this were the case, it would also be sending 12v down the aerial connection (although I'm not sure if that is part of the ISO standard)
- The blue wire on the adapter is to inject +12v into the aerial harness for the car. This could be for all head units, or just the ones that don't supply it from the aerial connection.
- If the above were true, I need to ensure that +12v is getting in to the aerial harness. If not from the aerial connection then via the blue wire. The simplest solution I'd imagine would be to take a switched +12v from the nav unit (amp on or similar)
Am I right on all of this? Any experience?
It will be a while before I have the time to pull the car apart again (I realize a multimeter will give me at least half the answers I need) and I would like to know exactly what I need to do beforehand.
To add, there is obviously a chance that the physical aerial connection is not great. Probably a contributor, but I do think it is more than just that.
Terrible pictures of the connections below:
https://www.navi4all.com/wp-content/uploads/2019/02/PS88MTVL_8.jpg
https://www.navi4all.com/wp-content/uploads/2019/02/PS88MTVL_7.jpg
Thanks in advance...
SteBrown91 said:
The blue wire is to power the amplifier on the adaptor. You just need to connect it to the switches live on the head units adaptor harness (using a scotch connector or a bullet connector if the harness has a second connection which they sometimes do)
Thanks for your response.I’ve seen references to phantom adapters (that simply push 12v back into the harness) and proper inline amplifiers, like you describe. I thought more of the former looking at the packaging (and cost, it was free in the box).
I think the answer is to get 12v to it and see what it does, whilst also having a play with the connections. If that doesn’t work, get a separate amplifier, which should work either way.
Does anybody have any specific advice for VWs over the same period? Anything obvious I am missing for this type of unit? The nav unit was set up for USA radio when I got it. Swapping to Euro definitely improved things.
Tommie38 said:
Thanks for your response.
I’ve seen references to phantom adapters (that simply push 12v back into the harness) and proper inline amplifiers, like you describe. I thought more of the former looking at the packaging (and cost, it was free in the box).
I think the answer is to get 12v to it and see what it does, whilst also having a play with the connections. If that doesn’t work, get a separate amplifier, which should work either way.
Does anybody have any specific advice for VWs over the same period? Anything obvious I am missing for this type of unit? The nav unit was set up for USA radio when I got it. Swapping to Euro definitely improved things.
If the aerial amp is not being supplied a 12v, you will have no AM and poor FM. The AM test is the most obvious, the poor FM less so.I’ve seen references to phantom adapters (that simply push 12v back into the harness) and proper inline amplifiers, like you describe. I thought more of the former looking at the packaging (and cost, it was free in the box).
I think the answer is to get 12v to it and see what it does, whilst also having a play with the connections. If that doesn’t work, get a separate amplifier, which should work either way.
Does anybody have any specific advice for VWs over the same period? Anything obvious I am missing for this type of unit? The nav unit was set up for USA radio when I got it. Swapping to Euro definitely improved things.
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