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-   -   Cellphone interference in car speakers (https://www.team-bhp.com/forum/car-entertainment/38292-cellphone-interference-car-speakers.html)

To the Gurus:
I got my ICE setup for my Swift diesel recently and discovered that there is a lot of cellphone interference through my speakers.
After trying(unsuccessfully I must add) to identify the cause, I took the car to my installer (Sound Factor) and surprise, surprise, there was no problem at all and everything seemed normal. I took couple of spins with the installer and after looking quite stupid, I dropped him back and made my way back home grumpily. And again, it happened...the irritating sound (like the one you get when your cellphone is close to your landline) was back. After spending more time trying to troubleshoot, here's what I've discovered:

• the interference occurs in all source modes i.e tuner, USB, CD.
• engine running or not does not have a bearing on the interference (happens in both states).
• bluetooth on or off also does not affect the interference (happens in both modes).
• I just now found out that the interference happens when the cellphone is close to the HU or placed on the front co-passenger seat. If I leave the cellphone in my pocket or near the driver side door, then there is no interference.

I've never had this problem before in my earlier cars or in other cars that I've travelled in. My ICE setup includes a Pio 5090 HU, JBL GTO 607c components, and JBL GTO 637 coaxials at the rear.
My cellphone is a Nokia 6151 and am on an Airtel connection.
Any inputs on solving this problem will be greatly appreciated!! please:

This is likely to happen with any HU
* when a call is active
* when a call is being connected or disconnected
* if GPRS is on and there is data activity

Did you check by actually trying to make a call when you were testing?

Solution? The simplest is to keep the handset away from the HU. Also, check the grounding of the outer shell of the HU.

Thanks DerAlte
Yes, I did try making a call while I was testing.
The interference occurs when a call is about to come in or when a number is being dialled. After connectivity, the interference goes away.
The closer the handset is to the HU, the louder the interference.

How do I check the grounding of the HU? Will the installer help me with this or will I need the help of an electrical guy? stupid:

Also when the phone changes/switches the cell tower.

Found quite an interesting article after some Googling:
macosxhints.com - How to prevent iPhone audio interference in speakers

The suggestion is to use some aluminium foil behind the cellphone to prevent the interference.
I tried that and voila, it worked!! Also, juggled with removing and replacing the aluminium foil. The interference was not audible as long as the aluminium foil was behind the handset, and came back as soon as I removed the foil.
The HU in my previous car was a Sony 5500 (I think...) and it had an aluminium trim around the border. Maybe that was what prevented the interference. My current HU is a Pio 5090 and has no aluminium trims.
It would be interesting to know from fellow T-BHPians their experience of HUs with/without aluminium trims with regards to cellphone interference.

I never had any cellphone interference in my Pio 2950 when using any of the cellphones.

Did you try using any other cellphones other than Nokia 6151 ?

Yes, I've tried a MotoSlvr and couple of other cellphones. Same problem. Interestingly, a co-worker at office has the same HU in an Alto and faces the same interference problem. Quite weird :Frustrati
Will try visiting my installer over the weekend for any possible solution.

If you have the habit of leaving the cell phone on the dash, under the HU (on the double DIN space) this will happen, look at the bright side, i use this to intimate myself, of incoming calls :)