I've also read that there are different types of ferrite core and which one is best will depend on the frequency you are trying to shield from. Farnell apparently make some good ones (although I admit to knowing very little about all this so couldn't really say!) and they do a large range of cores for various different frequencies.
Which leads to the question....does anyone know what frequency an A129 Pro would produce?!
Exactly!Yes I just noticed that as well. Given it's advertised as being specifically for shielding dashcams from DAB radio, I'd very much hope that was the correct frequency range!
I guess you want one that absorbs DAB frequency well, which for most of us will be in the range 200-300MHz, so you don't want a GHz ferrite core, but any that have a range centred around 200MHz would do, and 100MHz or 300MHz is probably close enough since they normally have a wide frequency range. But I think there is a lot of guesswork involved, there is no way of knowing what effect it will have on the video signal, so best to go with a recommended one if possible.Which leads to the question....does anyone know what frequency an A129 Pro would produce?!
I'm sure that installing a proper antenna is always the best solution, the windscreen ones are only adequate, and that is with the car in factory condition with nothing added!
That is the problem with digital radio, it either works perfectly, or it works terribly! A very small change in reception or interference can make it useless.
It has to be both, it is impossible for any digital electronics to operate without causing some interference, it can only be minimised, while a cheap DAB rooftop antenna will pick up a much better signal than a windscreen antenna. Of course with DAB it is hard to hear any difference in signal quality, until it stops working.Or maybe DAB radios should be shielded against any outside intereference?
Or maybe DAB radios should be shielded against any outside intereference?
I believe there are standards for rf emissions which the dashcams comply with. It is the car that can't cope with devices even when they are operating within the standards that is the problem, but there is no standard that ensures that cars are fitted with adequate antenna to avoid problems, thus the car manufacturers save a $ per car by fitting a stick on antenna instead of a proper one, and because we now have digital radio which works perfectly until it doesn't, the car manufactures can get away with it when 20 years ago in the analog age they always fitted high quality antenna since the owners could hear the difference during a test drive.
I'm sure this is true but the conclusion of your logic is slightly off-course. Both car and dashcam manufacturers are at fault here- both could be designed better to mitigate possible interference but neither does because of costs and because only a small percentage of users will have problems. Neither is free of fault but it's not easy to design against all possible problems so nobody does that- they only design against common problems. Carmakers can test with what they install, but not all aftermarket devices so that's why their stuff works but cams might not
As far as DAB, I think more fault is in the car designs where better antennas and better cable shielding almost always cure these issues. When you consider that even a slight cost increase will make huge financial numbers given how many cars of a particular model are made, then we should expect this as the norm. Dashcam manufacturers have lesser numbers involved but also lesser total profits, so they're not going to spend to do better either
What we really need is higher standards of non-interference for electronic devices- they're all quite nasty EMF/RFI polluters. That will cost us as consumers though so until the problem becomes more widespread (which it will with our thirst for more and better wireless devices) then we have to find our own solutions.
Phil