Ddpai affecting cars DAB signal

[Bad-Alias]

Hi all

I have just installed 1 x mini 3 up front and 1 x mini one at the rear.

both are hard wired with there own hard wire kit

yellow to + on battery
back to - on battery
red on a piggyback fuse that comes on with the engine.


The problem I am having, is when the rear camera is plugged in, I lose DAB signal in my car, unplug the rear camera, and it works again.

What could be causing this please? I think it is something to do with the rear camera?

would changing to the mini 3 at the rear be better?

both my mini 3 and mini one are the 3.5mm jack version, both running up to date firmware.

Front camera mounted on the window at the very top.
rear mounted on the window at the top

my car is a bmw 1 series

many thanks

 

[SawMaster]

Welcome to DCT @Bad-Alias

You've encountered a well known issue with dashcams, and while there is often a way to improving things, it doesn't always happen and it isn't always a full cure

Check the thread HERE for help with this. There are more links posted there as well. Something which may not be mentioned there is that apparently many car manufacturers use cheap and nasty DAB antennas which can be more prone to intereference. If after trying the recommended fixes in that thread you are still having problems, it might be worth trying a better aftermarket antenna But save that for last because the main problem is almost always location-related and even the best antenna won't fix that.

Phil

 

[jokiin]

my car is a bmw 1 series

antenna in the rear roof/window area?

 

[Bad-Alias]

antenna in the rear roof/window area?

it is yes, it is in the small fin on the roof

 

[jokiin]

going to be a challenge to try and overcome the signal issues

 

[Bad-Alias]

I have found this ''
High-Shielding Conductive Adhesive Tape
''

would sticking this between the DAB areal on the roof and the camera help it work better?

https://www.amazon.co.uk/gp/B07CRLCGCH

 

[SawMaster]

Best to try the suggestions in the thread I linked as they will be the most effective. The metal car body will already shield the antenna itself and I presume the cable to it is already shielded so I doubt that there's anything to gain with that tape

The basic problem is that EMI is getting through the existing shielding or bypassing it. As radiation of all kinds has a power to distance ratio based on squaring of numbers, an added unit of distance reduces it's power exponentially which is why distancing between components and cables is most effective here Ferrite chokes can stop EMI from traveling beyond where they are placed and are usually easier to do so give them a try as well.

With the DAB antenna being centrally mounted, try moving to cam to one side (away from the antenna cable if you know where it's routed). You'll still have a good FOV for the cam and that alone is the most effective of all the solutions since there's usually more EMI originating in the cam than in the cabling. As you experiment, use painter's tape to hold things in place as you test to facilitate the moving while emulating the (hopefully) final installation as closely as is possible.

Sorry there's not really any easier solutions here, but there's just no getting around nature's laws on how things like EMI work.

Phil

 

[Bad-Alias]

Hi Phil

Thank you for your reply

I have been playing about with different locations, and I have found one place so far where the dab works but move it a inch or so forward or back and the signal is lost.
I have ordered some farried cores to try also. But I think my problem is from the camera and not the cable.

Fingers crossed that this position works well when driving around.

Thanks again

 

[SawMaster]

Location can be sensitive like that if the EMI is leaving the cam in a specific direction or if the 'sweet spot' doesn't allow any bypassing of shielding found with other locations. Here's to hoping the ferrite chokes complete the cure for you

Phil

 

[Bad-Alias]

thanks you all, I found a sweet spot and added a couple of the ferried cores, and fingers crossed, all is working well.

many thanks