PCCM+ DAB+ Reception

[911-C2]

I drove my car for the first time today since fitting the PCCM+ just before the New Year.

I thought I had the DAB+ stuff sorted by bypassing the amplifier in the Drivers Side A Pillar and then bypassing the Diversity switch in the passenger footwell.

The DAB reception is poor, something seems not right. I am wandering if I bypassed the right aerial in the A-Pillar......

I dont seem to have a picture of the A-Pillar but below is what I bypassed in the passenger footwell. If I unplug that cable I get zero DAB so assume its doing something.

Anybody else have DAB issues or can definitively tell which wire in the a-pillar and footwell should go to what?

Apart from this issue the system is awesome.... spotify and waze in a car nearly 20 years old......

 

[esendia]

This is from the installation instruction, what is in your picture does look to be correct. I'd double checking the A pillar but I have had about 3 other people contact me regarding regarding poor DAB reception, all having the diversity system rather than the single antenna you get in a non PCM car like myself.

My belief is the length of the cable going down under the seat then back to the windshield before it gets to the antenna makes for poor reception compared to the single antenna that goes directly from the radio to the windshield antenna in a pretty short route.

If you have no luck I'd try a cheap DAB antenna rather than trying to bypass all the diversity system or look into a aftermarket wire that has the connector in the A pillar directly to the Fakra connector on the radio.

 

[911-C2]

Thanks for this, I am going to double check.

I'm pretty sure the diversity portion is correct as its keyed and if I remove the jumper I get no signal.

Looking at that picture of the Amplifier you provided in the instructions, it looks upside down to what I have. I have a coax connector at the bottom and the middle and I used the bottom one. The diagram looks more like the middle one is used.

I guess I need to buzz it out with a multimeter to be sure as something is amiss. By poor reception I mean virtually unusable, especially when driving.

 

[Dammit]

I had terrible DAB reception until I earthed the stereo separately - once it had it's own earth the DAB reception got much better, and a "schrp schrp schrp" noise that had driven me insane for years on the FM reception went away.

 

[911-C2]

Ok, I have solved this with my multimeter by taking the A-Pillar trim off again and this time fully removing the Diversity Control Module.

The long and the short of it is the bypass cable only fits on one of the aerial cables in the A-Pillar, the gold smaller one. In my car this traces out to the "non keyed" portion of the Double Cream connector at the Diversity Control module. As it was at the non keyed portion of the connector I was connecting the bypass to the wrong cable.

I simply swapped the cables in the Diversity Connector and have perfect reception now. I hope the pictures show the setup that works for me.

I wander if all 996.2 cars are wired like this.........

 

[Robbidoo]

Necroing this thread as I figure it's as good as any. I recently fitted a Pioneer head unit and used a DAB/FM splitter on the standard 996 FM antenna.

When I was testing it in my drive it was fine - which surprised me as I was expecting to need to pull the a-pillar apart and find some hardware to bypass.

But when I'm driving around I get DAB reception for about 5 seconds before it drifts out. It "feels" like an earthing issue or similar but I would expect a bad earth to affect everything on the head unit not just DAB. FM signal is fine for example.

Any thoughts?

 

[IUI675]

Have you checked to see if your DAB reception gets worse/better if you unplug the dab splitter from the car?

I had the same symptoms of you, after unplugging the dab splitter from the car aerial, reception improved when parked on the drive, which told me that I needed to do the wiring mods discussed above (bypassing the diversity module with a fakra to fakra cable from Amazon, swapping the terminals in the plug on the diversity module, fitting the cable from the pccm+ kit to bypass the module in the A pillar).

 

[Robbidoo]

If I unplug the DAB splitter I will have no DAB reception as I won't have anything to plug into the DAB antenna socket... all I have coming from the car is the "big" FM antenna. I removed the single-DIN tape-deck stereo so maybe that's where we differ.

Sounds like I need to get the thing apart and figure out exactly what's inline already.

 

[IUI675]

I mean unplug the dab splitter from the car, leave it connected to power and the head unit. Reception on mine improved when I unplugged that, which told me the stuff in line between the antenna and the plug was blocking the dab signal.

When you saw 'big fm antenna' do you mean the round silver plug with the pin sticking out the centre? Mine did start with pcm2 and most, so it may be wired differently (mine has a fakra connector for the aerial) although the symptoms are the same.

 

[9EtS]

If I unplug the DAB splitter I will have no DAB reception as I won't have anything to plug into the DAB antenna socket... all I have coming from the car is the "big" FM antenna. I removed the single-DIN tape-deck stereo so maybe that's where we differ.

Sounds like I need to get the thing apart and figure out exactly what's inline already.

Hi, did you find out what the root cause here ? Thanks.

 

[Robbidoo]

I didn't, I ended up having to fix a load of other things and never went back to this - I use BBC Sounds via carplay if I want radio.

There is another thread active where a chap is pulling apart his car to try and solve the same issue at the moment: https://911uk.com/threads/dab-aerial-options.125163/#post-2691265