I use this one from Amazon [https://www.amazon.co.uk/dp/B0D2MNRKWC?ref=ppx_yo2ov_dt_b_fed_asin_title] and I am surprised how well it works with the windscreen mount. I have had windscreen mounts before with bad performance but follow the instructions and definitely, as suggested above scratch/grind the paint off the metal and smooth it out with fine emery cloth or sandpaper and clean it, make sure all the copper strip is in contact with the bare metal. Also give the window a good clean before sticking, yes its a bit of a faf but its worth it. I have 92 stations with full signal and very few dropouts
Terrible DAB reception with official Mekede USB adapter
robdx2 Thanks. If all else fails I may give one a try (although I did read somewhere that most of the devices actually use the same chip?).
a month later
Well things have taken a turn, after installing the dudu7. In my original post above it was before installation I was still using an Eonon Q30pro head unit (topway TS18 based) and the signal was fantastic, could and often did, drive round the whole county(West Yorkshire UK) with barely any dropouts. Since putting in the dudu7 the signal is rubbish. Its 5 miles to my mums and thats down a hill, through a town centre along a road with high buildings either side, then up a valley with plenty of roadside trees, on the old unit full signal all the way, on the dudu its unlistenable most of the way.
Same dongle, same antenna. So whats different:
Reverse camera wires now run up same A pillar...Possible interference but unlikely as only powered when in reverse and set that way in dudu settings...I had no reverse camera on old unit
GPS antenna wire runs alongside dab antenna for about 100mm...possible interference, on old unit the cable was routed straight up and away from dab cable
I now have a DVR dash cam...very possible source of interference, though cables don't run together
Dab dongle plugged into new USB cables(USB2) on dudu which is the six pin, on old unit was plugged into the 4 pin one...its possible the new USB cables are not well shielded
I have a usb flas drive in USB1 and on old unit both DAB and flash drive were never plugged in together as only had 2 usb not 3 like the dudu and the 6 pin on old unit had a 4g modem always plugged in as no built in 4g and wifi on Eonon was rubbish.
I have an adas DVR in USB3 but that is a good 100 mm away from other 2 ports
I have a cheap usb c fast charge cable plugged into the usbc port on the back......very possibly badly sheilded as very cheap aliexpress thing
The dudu is Qled screen(I believe so anyway??) so could be a cause of interference.
So conclusion is that something on that list is causing inteference in the signal, it must be so maybe the OP is having similar.
My starting point will be to remove the dudu's 4 pin single usb and replace with the one from my old unit and remove the usbc fastcharge cable(which I won't really need anyway) and possibly fit ferrite cores on the DVR cable
Well by jove chaps I think I have solved it. Here is what I did and using Dabdream app I seem to have a 80-90% signal improvement.
I decided against swapping over the 4 pin USB for the moment and removing the fastcharge usb c cable because to do either of those it means taking apart the entire centre console to access the back of the unit, so instead I decided to ferrite core everything as they arrived early this afternoon.
I moved the dongle from one of the double USB slots to the single 4 pin slot and added ferrite cores to all 3 usb slot cables near to the slots.
Added ferrite cores to the usb c fast charge cable, the dvr camera cable at both ends and both ends round the plug in the middle of the cable.
Even added ferrite cores to the reverse camera wire where it runs alongside the antenna cable, and to the gps antenna and even the 4g antenna even though its on the opposite side of the windscreen. Overkill maybe but its a major major imoprovement.
After adding the cores I performed a rescan on DabZ and went from 82 to 92 stations. I also thought it was worth testing Dabdream( 86 stations but for some reason always gets a few less) and the DAB-H app that comes with a lot of these dongles (92 stations) so already a big improvement.
I then drove the 5 mile trip over to my mums as I know how that went on the old unit and how it went before making the changes so it would be an accurate test. On the way from home to mums I used Dabz where I had 3 to 4 minor drop outs of a second or 2. Halfway I swapped to DAB-H similar amount of dropouts but again no more than a second or 2. On the way back I used Dabdream and switched on the apps noise suppressor setting and I didn't have any full dropouts and was changing stations regularly. I even took a diversion at the last half mile along a road that runs through a forrest and only one dropout and that was at a known blackspot.
So would definitely recommend using dabdream app and having the dongle in the single 4 pin USB slot and adding the ferrite cores....These are the ones I have used https://www.amazon.co.uk/dp/B08ZSGFPTN?ref=ppx_yo2ov_dt_b_fed_asin_title
I had the same problem, I will try with the OEM DAB antenna, there is an adapter to buy between the screwing model (USB adapter) and plugin model (OEM DAB cable) 
Hi I tried the SMA/SMB adapter today. It works perfectly. All DAB channels are received at full power (quite a few were with low power with the separate antenna) so I will just remove the provided antenna. There is a small caveat: the physical connection with the SMA/SMB adapter and the OEM DAB is weak. You need some strong « gorilla tape » to make sure it stays connected
- Edited
You need to verify if your OEM DAB antenna has small/big SMB and on the DAB stick side male/female SMA
There are also FAKRA to SMA/SMB adapters
Thanks for the suggestion. Yes the Fakra connector is a better option. Definitely more reliable.