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Discussion Starter #1 (Edited)
so only just purchased this 2015 Q50 hybrid S Sport Tech and love the car. The only issue is that i have no DAB or FM signal. All settings are on for DAB, it just displays 'No Signal'. So no radio at all.
So looking at the wiring diagram the Dab and rear screen FM signal all have a different path to the AV head unit. I have performed the diagnostic tests and everthing comes back ok.
Its looking like at this stage the head unit to have both DAB and FM fail with no signal. Every thing else works perfectly with the entertainment system, just simply no signal.
 

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Discussion Starter #2
So i managed to get another radio, amp and sat nav as the whole unit, its still the same. I still get no DAB or radio antenna signal. Can anyone suggest anything else. There has to be something common to both DAB and Radio antenna other than the radio unit and amp?
 

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2017 Q50 Red Sport 400 RWD
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We don't have Digital Audio Broadcasting (DAB) here in the U.S. We have High Definition Radio (HD Radio). Do you get AM reception? Can you play CDs? Have you tested your antennas? The problem with the antenna theory, is the satellite antenna (roof shark fin) is different than the AM/FM antennas (rear windshield) so it's hard to think both went bad. So what is in common with the AM/FM and satellite signals? The AV control unit. But then I would think you'd have other issues like no AM reception, no CD audio, etc. Maybe it's your antenna amplifier? I don't know, sorry!
 

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Discussion Starter #4 (Edited)
Well i have replaced the AV unit as i thought that according to the wiring diagram only the FM/AM goes through the AMP. The DAB was a straight line into the AV unit. The AMP is located in the rear LH quarter panel, however when looking at it the roof aerial (DAB/HD) and FM from rear window aerial both go into that unit. So ordered a 2nd hand one. if i go to diagnostic mode the AV system tests ok.
Everything else works, CD, bluetooth, Aux etc is perfect, just displays 'No Signal' when i try to tune radio.
I shall post back when i have replaced the FM/HD Signal Amp.
 

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2017 Q50 Red Sport 400 RWD
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Well i have replaced the AV unit as i thought that according to the wiring diagram only the FM/AM goes through the AMP. The DAB was a straight line into the AV unit. The AMP is located in the rear LH quarter panel, however when looking at it the roof aerial (DAB/HD) and FM from rear window aerial both go into that unit. So ordered a 2nd hand one. if i go to diagnostic mode the AV system tests ok.
Everything else works, CD, bluetooth, Aux etc is perfect, just displays 'No Signal' when i try to tune radio.
I shall post back when i have replaced the FM/HD Signal Amp.
The antenna amp is sounding more and more like the culprit. Yes, both satellite and AM/FM go into the amp. Does your AM work?
 

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The antenna amp is sounding more and more like the culprit. Yes, both satellite and AM/FM go into the amp. Does your AM work?
To be accurate, there are three antenna inputs going into the AV Control Unit: AM/FM Main, FM Sub and Satellite Radio. The AM/FM Main antenna and FM Sub antenna are attached to the rear window. Only the AM/FM main antenna goes through the Antenna Amp. I believe the FM sub antenna is part of a Diversity Tuning system.

When listening to the radio, a special electronic circuit monitors the signal strength at both antennas and electronically selects between the stronger of the two. The speed at which this switching process occurs is so rapid that the listener does not even perceive that it has taken place.

Systems that incorporate diversity tuning have excellent multipath rejection. Multipath is that swishing sound you hear when driving around large buildings, structures, or mountains. It is created by the reflections of the radio signal reaching the tuners antenna a brief instant after the direct path of the radio signal. These multiple path (multipath) signals can vary from an in phase condition to one that is completely out of phase at the antenna. When the signals are out of phase, the quality of the reception is very poor. By using two antennas, it is extremely unlikely that multipath signals will be out of phase at both antennas simultaneously, thus assuring good reception at one of the antennas at all times.

This is primarily for close FM broadcasts as multiplexing is more predominant when the signal is strong. I think that's why the FM Sub antenna does not run through an antenna amp. If there is a weak FM signal from a station further away, multiplexing isn't as prevalent so it isn't necessary to amplify the FM Sub antenna to counter it.

Here's a few diagrams:

94060


94059
 

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2017 Q50 Red Sport 400 RWD
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To be accurate, there are three antenna inputs going into the AV Control Unit: AM/FM Main, FM Sub and Satellite Radio. The AM/FM Main antenna and FM Sub antenna are attached to the rear window. Only the AM/FM main antenna goes through the Antenna Amp. I believe the FM sub antenna is part of a Diversity Tuning system.

When listening to the radio, a special electronic circuit monitors the signal strength at both antennas and electronically selects between the stronger of the two. The speed at which this switching process occurs is so rapid that the listener does not even perceive that it has taken place.

Systems that incorporate diversity tuning have excellent multipath rejection. Multipath is that swishing sound you hear when driving around large buildings, structures, or mountains. It is created by the reflections of the radio signal reaching the tuners antenna a brief instant after the direct path of the radio signal. These multiple path (multipath) signals can vary from an in phase condition to one that is completely out of phase at the antenna. When the signals are out of phase, the quality of the reception is very poor. By using two antennas, it is extremely unlikely that multipath signals will be out of phase at both antennas simultaneously, thus assuring good reception at one of the antennas at all times.

This is primarily for close FM broadcasts as multiplexing is more predominant when the signal is strong. I think that's why the FM Sub antenna does not run through an antenna amp. If there is a weak FM signal from a station further away, multiplexing isn't as prevalent so it isn't necessary to amplify the FM Sub antenna to counter it.

Here's a few diagrams:

View attachment 94060

View attachment 94059
So what is your diagnoses to pdt's problem Dr. Avedis?
 

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Let's be clear here. DAB is not received on the satellite antenna on the roof. That's for satellite radio. DAB is broadcasted digitally on a higher frequency than FM but it is still terrestrial-based and received on the FM antennas.

I'd say the antenna amp is the first thing to check out and if that's not the problem, then I'd started checking wiring continuity from the glass antennas to the antenna amp and then from the antenna amp to the AV Control Unit.
 

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2017 Q50 Red Sport 400 RWD
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Let's be clear here. DAB is not received on the satellite antenna on the roof. That's for satellite radio. DAB is broadcasted digitally on a higher frequency than FM but it is still terrestrial-based and received on the FM antennas.

I'd say the antenna amp is the first thing to check out and if that's not the problem, then I'd started checking wiring continuity from the glass antennas to the antenna amp and then from the antenna amp to the AV Control Unit.
Oh!
 

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Discussion Starter #10
So Antenna Amp replaced and fault still there. This is now baffling as to why there is no FM, AM or DAB signal.
As i have replaced all the multimedia components in the centre console as one unit and Antenna Amp in the rear, i really have to start looking at wiring and continuity.
 

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2017 Q50 Red Sport 400 RWD
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So Antenna Amp replaced and fault still there. This is now baffling as to why there is no FM, AM or DAB signal.
As i have replaced all the multimedia components in the centre console as one unit and Antenna Amp in the rear, i really have to start looking at wiring and continuity.
Bummer. Is it possible your rear windshield was replaced and the antenna wiring was damaged or not plugged back in correctly?
 

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Newport, Oregon
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Damn! I'm about tapped out here. Did you have AM before the antenna amp swap? Is the antenna amp getting power? Wiring and continuity checks are the next step but if that doesn't pan out, maybe the AV Control Unit?
 

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Discussion Starter #13
i have replaced the AV Unit. I do however have a hunch, i only just purchased this car and the radio has never worked with me. The previous owner had fitted window tint film in the side and rear windows. I just have a feeling it might be causing the issue. I have known it to degrade on other cars if fitted to the rear window but not to stop the signal completely. I will make my own aerial and bypass the rear window with it and report back to you guys.
 

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i have replaced the AV Unit. I do however have a hunch, i only just purchased this car and the radio has never worked with me. The previous owner had fitted window tint film in the side and rear windows. I just have a feeling it might be causing the issue. I have known it to degrade on other cars if fitted to the rear window but not to stop the signal completely. I will make my own aerial and bypass the rear window with it and report back to you guys.
Geezus! You didn't mention that earlier. Section 4, Page 3 of my Owner's Manual says:

" Do not place metalized film near the
rear window glass or attach any
metal parts to it. This may cause poor
reception or noise."


If your tint is metalized, that could be your problem. Ceramic tint should be used on the rear window.
 

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Discussion Starter #16
So disconnected rear window aerial and rigged up my own but still no signal, so at this stage i will assume the window film is not the cause.
So checked power supply to Aerial Amp and i dont seem to be getting anything.
The connector from the Amp does however go into the roof lining towards the Roof Satellite Aerial, does it get its volts from there?
If so what voltage is it? If its 12v then thats easy to get from elsewhere.

Key point here is where the Amp gets it power source from. Almost there!
Thanks for the comments so far.
 

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Discussion Starter #17
so have checked all the back end out, the LH rear quarter houses the Amp and the RH rear quarter houses the mixer unit
94115
94116
94117
94118
 

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Discussion Starter #18
So i am convinced its a power supply issue to the Amp and that by looking at the wiring in the roof, goes to the front.........
 

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European cars have that DAB Mixing Unit and we don't so I'm unfamiliar with how the wiring is arranged and what inputs and outputs it has. Also, I don't know if the pinouts on the connectors are the same for your car. But assuming they are:

The Antenna Amp is 12 VDC. It receives power from the AV Control Unit. The Antenna Amp has a 2-pin connector wire that goes to the AV Control Unit .

94119


Pin #1 is the Antenna Amp On Signal which should be 12 VDC. Pin #2 is the amplified radio signal from the antennas. That 2-lead wire goes from the Antenna Amp along with the FM Sub wire to the AV Control Unit that you replaced in the front console.

The AV Control Unit has many connectors on the back side. There is one 3-pin connector that carries the FM Sub, AM/FM Main and Antenna Amp ON signal from the rear of the car. Pin 150 carries the FM Sub, pin 151 carries the AM/FM Main and pin 152 carries the 12 VDC Antenna Amp ON signal.

94121


Again, I have no idea if this is the same for your car. I don't know where the DAB Mixing Unit connects into all of this. Can you see how it is wired? What are its inputs and outputs? If it has its own power supply, could it be the problem? I have no idea.

I would think you should see a 12 VDC signal at pin 152 when the AV Control Unit is powered. Likewise, a 12 VDC signal on pin 1 of the Antenna Amp connector.

I don't know if any of this helps you but it's all I know.
 

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Discussion Starter #20
94158

Here is a stock pic of the DAB mixer, as of yet i do not know where it sits in the system and which are input or output connectors. It does not seem to have a power supply. Managed to get a 2nd hand one cheap from Poland so at least i will have spares for everything!
Not the best way to go about things but next i will check the power outputs from the back of the AV Unit.​
 

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