Will an independently wired microphone from a kit suffer from which the interference the factory wired one suffers? Is there an obvious culprit or cure for the interference?

I feel slightly embarrassed as I'm completing nearly six years after I started what should have been a simple project, thanks to StevePAA's help and gift, .

I've installed a Nokia CK300 bluetooth handsfree using a Nexxia/Autoleads harness, the Jaguar's factory wiring and StevePAA's connector for RT2 and 5 in the trunk.

With the engine off, everything works fine, muting, call set up, call quality etc.

With the engine on, when I make a call, I send to the other end a loud, high, variable pitched whistling interference along with my voice. The incoming audio to the front speakers is fine.

If I plug the Nokia mike direct into the blue tooth receiver, with the mike wiring 'loose' in the cabin, away from the body of the car, the interference cannot be heard.

I'f also tried an OEM jag microphone into the overhead console - whistling interference on outgoing audio.

The whistling is RPM dependent - higher the RPM the higher the frequency. I think at above 3000rpm it is no longer audible, though it suppresses my "testing 1-2-3 messages".

I've done obvious things like clean and reconnect connectors. One of the connectors in the boot was recently replaced with the replacement's leads etc soldered and insulated.

I'm going to get a Parrot with its microphone installed - but I'm concerned it could be impacted by the same issue. Advice most welcome.

 

Alternator noise suppressor as this removes the AC signal the gets past the rectifier as you want a pure DC power source . The stray AC signal frequency is dependent on the alternator rotation speed . One way to test this with is the stereo AM receiver .

 

Thank you - have not tried the AM radio with the engine on. Will check it tomorrow am.

Just had a service and spark plugs were changed, so will check those as WhiteXKR indicates they are a source - though I'd expect clicks rather than a whistle?

 

So, you seem to say the noise is dependent on the routing of the microphone wire. Have you tried re-routing it? Or, conversely, insulate it more, like wrapping it in aluminum foil? Not saying there is no underlying issue, but n=maybe these tricks will be enough to get this setup usable for now...

 

I've tried foil in places - no luck.

I get "static" type noise with engine off, ignition on - so I assume it is not the alternator.

I'm wondering if the "whistle" noise is actually high frequency clicks from sparks.

I need to get someone to listen to the noises....

 

Paddy, I looks like I might need a little more info to help out here. It sounds like the microphone or mike cable is picking up RFI from the alternator or you have bad connections somewhere.

Can you tell us about the system's hook up? Where and how did you connect to power (both ignition on and battery)? Where, how, and how many times is the unit grounded? I want to know the ground connection is good, tight, properly placed and to eliminate ground loops by inadvertently grounding the chassis to 2+ sites.

When I say How, I mean type of connection (twisted wire, soldered wire, male female pins, did you crimp on any connectors?). Bad connections are a prime source of introducing noise.

Help me understand the different microphone you mention. Do they each connect to the unit the same way? Did you say some make the noise, others do not? Is some dont, what is different about them.

Btw, can you, the transmitter, hear any noise or is it only on the receivers end?

Paddy, If you feel like diving into this further, let us know. If not I understand.

John

 

Many thanks for taking an interest John,

• Interference is receiver end only
• One option is OEM microphone, factory wiring and connectors only, as per original condition, plus a Nexxia adaptor harness
• An exception to factory wiring and connectors only is that I had to replace a connector (RT2) with one from a breaker's yard, which has been connected using soldered connections and heat shrink

I've also connected the kit microphone (ie the second option) to the factory wiring using an adaptor that uses a compatible connector to the car's factory wiring and provides a 2.5mm jack for the kit microphone. I get the same noises with this option. A third thing I have tried is to connect the kit microphone to the BT receiver "loose" ie just for testing, connected it without any installing or routing within the car. All of these options use factory wiring and unaltered kit components,

With the ignition off, the system works fine. As indicated above ignition on/ engined off or on produces the interference. (would I be right in discounting the alternator as that would not be active if the engine is off and it is not rotating?)

I'm assuming by using the car's factory wiring, the grounding etc is fit for purpose. Ignition on and battery is provided from the car's "Radio Telephone" (RT connectors, connecting to a Nexxia harness that splits out ignition, battery and mute to interconnect to the Nokia CK300, and provides 3.5/2.5mm jacks to connect to the BT receivers speaker output and microphone input sockets.

From the comments I have had so far, my best guess would be one of the soldered connections for the new RT2 connector (eg the one's for the microphone) is bad or some issue related to new spark plugs is creating an issue. (Hmm - will try shielding the ignition wire....)

I'll give it a few days for more advice then I'll try installing the kit microphone, which is the best bet - I'll have to put my stubbornness to make it work on the factory wiring behind me......

 

Don't think you said this so verification: both (all) microphones you've used make this noise in receiver's speaker when transmitting car has ignition on.

1) absolutely yes discount alternator since this happens without engine running.

2) how can you test it with ignition off? What is power source battery only? By that I mean car battery.

3) for a this unit connect to any ignition power at all?

4) I'm beginning to suspect defective bt unit. Can you please tell us more about what this bt unit does? What brand model? Best yet are installation instructions on line?

I was trying to think of way to isolate bt head unit performance without mic connection, but can't visualize this system.

Afterthought: if all mics whistle, could the mics ground connection (grounds shield inside wire) be open or intermittent?

Ahh Paddy I better stop speculating til I have a better picture.

John

 

There is a noise suppressor on the fuel pump harness , but not on all X100's . To test pull the fuel pump relay(s) then turn ignition on before start detente . There are 2 fuel pumps on the supercharged models .

 

Just thought: if you can use it ignition off, noise only happens with ignition on, it's almost certain that you have an ignition connection (power to unit from ignition on source). Disconnect that ignition power source. Noise gone?

Yes- that ignition power source wire is the culprit.

No - we just proved that the bt unit doesn't know whether ignition is on or not. The only difference it'll se is battery voltage level.
Whistle is introduced by something in the car that transmits with ign on.

A) we have to figure how signal enters transmission circuit.

Let's hope noise goes away with ignition wire disconnected.

John

 

I gave up on the factory fitted microphone wiring and ran a Parrot mike to the armrest.

All working fine.

Thanks to everyone for taking an interest.

 

I'm glad it worked out for you. Thanks for the update, sometimes it's frustrating when you spend time trying to help someone out and the thread goes silent with no feedback.

So it sounds like a defective microphone. Hey as I typed this it occurred to me: if you have a chance, please post the make and model of that defective microphone for future reference.

John