Audible oscillation from...?

Howdy folks.

Just got my hands on a RAK4630 with a 5005 running the meshtastic kit. I have done nothing but take it out of the packaging, plug in the antennas, and plug it into USB. Best I can tell its functioning, but I haven’t done anything with it one way or another. As such no problem with that.

However, I’m noticing a curious audible high frequency whine coming from the device at regular intervals. I’d guess it’s from whenever there’s a spike in power draw since it coincides with the LED lighting up. It’s not especially loud, but I can hear it easily enough when it’s sitting on my desk (~18 inches from ears?).

So, my question(s): is this normal? Has anyone else observed this noise and/or pinpointed where it’s coming from specifically? Assuming it isn’t indicative of some other issue, it’s not actually a problem, especially if it’ll live in a case. More so just a curiosity to me.

Otherwise, I’m quite a fan of what I’m seeing so far. :grinning:

Welcome to the forum @steve

Some of the base boards are creating a nice coming from the inductors of the voltage regulator, if you here it while the green or blue LED is on it is most likely caused by current raise when the module is transmitting a packet over LoRa.

It is normal and is no defect.

I poked at it a bit more and yes that does appear to be what I’m hearing. It seems to have a quiet but constant audible noise that mostly blends into the background, and then when it transmits it’s relatively louder.

Nothing harmful, I have 10 different WisBlock Base boards laying around here, some are making a little bit of noise, others don’t.