Fixing the nRF24L01+ “magic finger” antenna problem @ncrmnt

Necromancer’s notes documents nRF24L01+ radio modules that only seem to work when you touch the antenna:

A quick googling found out that a problem is well known. There are a dozen or even more threads on the arduino forums and others. Here are some of them:

• nRF24L01+ only working when I place my finger on it
• NRF24L01 failing. Placing finger on aerial fixes it!
• Problem using nrf24l01+ modules. Print details seem ok. Only work when touching.

And the list goes on. All recommendations were down to “throw those into the garbage bin and order from a different seller” & “Needz moar ceramic capacitors on the power rails“.

As expected, a ton of capacitors of various kinds, shapes and sizes didn’t help much, oscilloscope showed no issues with the power. So, what’s so magical about my finger?

Looking at the schematic vs the boards showed one difference:

C6 is missing from all my nRF24L01+ modules. Like every single one of them, even those working with no problems! I marked the place on the next photo (above) where it should theoretically be.

Success! And what happens if we solder it?

Magic happens, the modules flashed and worked with no big issues, just as if my finger was placed on them.

Read more on the post here.