I feel your pain. If we were smart then we wouldn't have DAB+ recpetion problems. I have two identical headunits with same stick on DAB+ windscreen aerials in our cars. The signal is sketchy but we do have much more consistent reception with the Jimny and its more upright windscreen compared to the lower height and steeper slope of the Mazda. The location of the aerial seems to be the blame for me. There isn't *that* much difference in physical height and angle position between them but it clearly shows how picky DAB+ can be,
I also have a cheap DAB+ in the shed which uses the same car windscreen aerial stuck onto the shed's clear roof panel. It works fine 100% of the time but doesn't have to move
It did take some fiddling around to find the right spot for that also. The shed DAB is just a car kit with a USB powered DAB+ receiver plugged into computer speakers + subwoofer and works really well.
As a side point, does your headunit have signal seeking setting which I think tells it how long to stay on the same frequency before hunting for another? Not that I think there a multiple stream broadcasting the same channel but might be worth a try. I have fiddling with it but didn't make much difference at all for me. The signal loss just falls off a cliff all at once.
Anyhow, the reception on the Mazda is the sore point for me. I have considered wiring it to the factory rear antenna but really need to get power up to the antenna to hopefully reduce any noise the hence new cabling is needed to get it done correctly. I have tried with the 12V DAB+ spliiter amp that sits behind the headunit and just amplifys both the FM and DAB+ signals but it ended up just dragging down the FM reception threshold making the FM a bit worse. The DAB+ worked the same but I also don't have the right antenna. Would also need the antenna to be replaced with one that can work in FM and DAB+ frequency bands.
I'm fine to give things a go but would like a firmer idea of the result before pulling things apart.
I assume that you have an external FM and DAB+ antenna? I guess you wouldn't have the windscreen mount. Could there be an amplifer up near the antenna which might have intermittant power supply issues when the car hits some bumps? Does the reception change when the car is not running and power is only drawn when in the accessory position? Is there anywhere when it works fine with the engine off and car is stationary in the strong signal area?
DAB+ is damn picky and the Mazda deck worked pretty well yesterday when I was out an about. The DAB+ being a higher frequency than FM just doesn't bend around corners or work well with geographic like hills as well as FM seems to tolerate. I don't mind spending time to nut it all out but aren't clear on the next steps yet. I have considered getting another stick on antenna and see if I can graft two antennas onto the one amplifier to increase the surface area it has to capture but it won't make it more pretty and I could well mess up the impedance by adding moar aerial. I don't think I need to do that much more but have to do it the right way.
