The Etsy QRO Miracle: Five Ferrites to Rule Them All
Ah yes... another glorious day in influencer engineering. Today’s hero? A YouTube hamfluencer proudly recommending “Super QRO Chokes” sold on Etsy — because nothing says RF confidence like handmade ferrite necklaces for your coax.
Five Sleeves of #31 – The Titan of QRO!
Five clamp-on ferrites on 7 mm coax, all #31 mix. Labeled “QRO.” Claimed to handle legal limit. Reality check: it’s not even a decent receive-only choke. At HF, that combo barely reaches a few hundred ohms of common-mode impedance — and by 20 m, it’s as useful as a paperweight with BNCs.
The QRP Edition: Three Sleeves of Shame
Because physics must be linear, right? Half the ferrites, half the power — perfect symmetry! Why design a real choke when you can simply multiply your Etsy listings by the number of sleeves? It’s marketing efficiency at its finest.
Ferrite Economics 101
• 3 sleeves = QRP (≈ 100 Ω Zcm)
• 5 sleeves = QRO (≈ 200 Ω Zcm)
• 7 sleeves = NASA Deep-Space Probe (≈ 300 Ω Zcm and a warm feeling inside)
Meanwhile, in the real world, a proper 1–30 MHz QRO choke starts around 5 – 10 kΩ Zcm, not 200 Ω. That takes stacked 2.4-inch cores, multi-turn winding, and materials that survive both voltage and heat. You know... actual RF design.
“It Works for Me!” — The Eternal Defense
Ah, the classic justification. “It works fine for me!” Sure — until your coax shield becomes an antenna, your neighbor’s TV glows blue, and your ferrites radiate harder than your feedpoint. It’s not a choke. It’s a Common-Mode Heater Kit™.
Closing Thoughts from the Burnt Lab
Friends don’t let friends buy QRO dreams from craft platforms. Measure first, brag later — and remember: if your QRO choke fits in a coffee mug, it’s not a QRO choke.
Disclaimer: this roast is for educational entertainment — no ferrites were harmed in the making of this article (though a few egos overheated).
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