981 Boxster after market head unit poor DAB signal

[Petrolhead]

I have installed a Poineer head unit with DAB.

I am using a stick on windscreen antenna which is earthed 9n the A pillar.

The problem is the signal is weak and ofter shows no signal. I have checked the earth and the connection on the back of the unit and all seems fine.

So I am wondering if I am the only one with this problem?

There are other antennas but the need to be mounted to the body ie https://incartec.co.uk/product/70-964-dab-amplifie...