nr51822: No radio with custom PCB

[Henry]

Hi,

I have created a custom PCB that more or less follows the Nordic SmartBeacon design: Beacon_V2.pdf

Instead of BAL-NRF01D3 I used the BALF-NRF01D3 as this is supposed to be compatible with the QFAAG0 chips, which I use.

So now, when I load the SmartBeacon FW, everything seems to operate fine: LED pulsing, change to orange LED on button press (DFU mode)...

But what is missing is that I cannot capture any signal on my iPhone on the custom PCB... With the original Smart Beacon HW everything works fine. On the custom PCB I use the same shape and dimension PCB antenna.

I already switched from external 32Mhz crystal to internal but everything stays the same.

Now, how can I find out what is going wrong? Is there a way to see wether the soldering of the Balun was ok?

Thanks for your help!

Henry

[Henry]

Here a picture of how the balun is placed.

Please let me know your comments

Thanks

EDIT: Attached please find a new version, this time with GND plane. Please let me know your comments, if this should be sufficient.

Thanks, Henry

[Asbjørn]

This look like a good improvement with regard to ground. It look like a really small board, but to me it seems like you have added the amount of ground plane on both top and bottom layer that you could. Because of its small size it wouldn't be the best performing board, but you should be able to get some OK range with this one nevertheless.

You should move the trace that runs under the L1 component. It seems to be a button (BTN2 or 3?), but it could be something else that's powered. Avoid routing signal traces underneath the trace from the balun towards the antenna. Would it be possible to use a gpio on the opposite side of the chip to avoid this conflict?