Craig - might be worth documenting? Maybe a "pre-requisite" section that goes out with the purchase email?
I also have a lot of interference from the DAB module that needs sorting. I'm afraid that this isn't the 'Ultimate' DAB/FM radio yet.
it is possible you are picking up noise through the power supply. All of the radio pcbs I built had matched filters so each filter was a matched pair of capacitors and inductor. In case you were not aware the tolerance on capacitors is typically +/- 10% and that can have a big influence if the filter set is unmatched.
I do not know if the ones craig distributes have matched filters or not.
If Craig could confirm that then please?
Just to be clear, when I say interference I'm talking about a high pitched noise from the ignition and alternator whine which I don't get from the Silabs (or the CarPC at all in fact).
It's possible you are getting a ground loop caused between the ground of the aerial you are using and the ground to the PC.
dont fight the noise... you prob wont win :)
use a HQ ground loop isolator
even for this a moderate qual one will do, for this...
the loop is prob from usb ground to the soundcard ground
(soundcards not made to be in a car)
and remember, the noise is flowing on all ground
it just entereds the audio, because of single ended designs of
of the input on the soundcard, also can get right into audio cable(even shielded) cause
alternator noise is low freq, shields due little to keep that out...
It's very possible that it's a ground loop problem, odd though that it's only an issue with the DAB unit. The Silabs is connected to the same aerial...............but the DAB is connected to the line-in of the sound card................
Then again, it's advertised as 'tweaked for the Car PC enviroment to avoid interference' which suggests these bases are covered? Maybe not until it goes audio over USB like a Silabs?
I'll do some investigation with grounding stuff..........and if I loose I might try an isolator.
like i said, sound card... they not made for automotive use!!!
audio over usb is completely differnt... noise anint getting into 1s and 0s
On the issue of noise, increasing the volume of the unit via the DAB_Master certainly helped with mine and my mast antenna. I have a small amount of alternator whine now, and have one of those filters mentioned above on order to see if that resolves it.
wolvers, there are a couple of things to check.
If you've installed a new antenna (or even if its the existing) check the base of the antenna is grounded. Car bodies are galvanised and a bit of sandpaper under the locking nut could be enough to sort your problem out.
also check your line in cable is double screened.
Additionally the radios I built have switchcraft connectors, you could try swapping the one on the board to that type but you need to check with craig for warranty and all that.
finally if you get stuck, send it to me and i'll have a look (I am in the uK)