Most of this week's crop was hashtag-heavy Shorts and factory clips, but this Brazilian lab video is a genuine hands-on RF exercise. A viewer in the channel's WhatsApp group posted an unknown coil and asked the classic question: on what frequency does this thing actually resonate? The host takes that question and turns it into a full bench workflow.

Expect to see practical techniques for characterizing an unknown inductor: pairing it with a known capacitance to form a tank circuit, sweeping with a signal generator or NanoVNA-style instrument, and reading the resonant dip or peak. For hobbyists who have a drawer full of scavenged coils from old radios, SMPS transformers, or unmarked toroids, this is exactly the skill that unlocks reusing them in filters, oscillators, or matching networks.

The channel sits at the upper end of the "small channel" threshold (~9.8k subs), but the format — a real lab bench, real test gear, and a specific measurement problem worked end to end — is what makes it worth the time. Portuguese narration with an Italian title quote, but the schematics and instrument screens carry most of the technical content, so language shouldn't be a barrier for most viewers.