HF Antenna Micro-Traps - DIY Build Project

This is the one you've been waiting for - the traps to go with the micro End Fed Halfwave (EFHW) antenna build. Here's how to make them. These traps will work with my Ultimate Ultralight EFHW (https://youtu.be/s-_LyhdGapM) or just about any QRP end-fed halfwave antenna, and you could even build pairs to use with a dipole. LINKS: - LC Resonance Calculator: https://www.omnicalculator.com/physics/resonant-frequency-lc - Toroid Winding Calculator: http://www.66pacific.com/calculators/toroid-coil-winding-calculator.aspx You'll certainly need some MATERIALS: - T37-2 Toroids (my usual): https://amzn.to/3hFsYlj - T50-2 Toroids (a little more efficient and maybe easier to build): https://amzn.to/2QCkGio - 28 ga Magnet Wire: https://amzn.to/3b9Isf4 - 39pF 100v Ceramic Capacitor (0603 case recommended): https://www.digikey.com/product-detail/en/kemet/C0603C390J1GACAUTO/399-15862-1-ND/7516362 NOTE: 100v is marginal for 5w. Consider a 500v or 1kv for better durability and/or higher power. - 500v: https://www.digikey.com/product-detail/en/kemet/C0805C390JCGACTU/399-7155-1-ND/3439396 - 62pF 100v Ceramic Capacitor (0603 case recommended): https://www.digikey.com/product-detail/en/kemet/C0603C620J1GAC7867/399-14992-1-ND/7382541 NOTE: Again, 500v model is needed for 10 or 15w. https://www.digikey.com/product-detail/en/kemet/C0805C680JCRACTU/399-7068-1-ND/3439334 Also, consider a few other capacitors in the 22pF - 100pF range, depending on the traps you'd like to build. - Perforated Prototype Board: https://amzn.to/35lcvzn - 5/8" Heat Shrink Tubing: https://amzn.to/3lwwGjt - 1/4" Heat Shrink Tubing: https://amzn.to/2G9bGzk And you'll need some TOOLS: - Dremel (or similar)high-speed rotary tool: https://amzn.to/3gFEkEL NOTE: I have had my Dremel tool for about 25 years now and it hasn't missed a beat. Based on my personal experience, I would recommend going with the name brand tool. - Diamond Cutting Wheels: https://amzn.to/2QBRHve NOTE: I really like these because you can't cut yourself with them, but they cut the perf board and BNC connector brass just fine. - Soldering Iron (any will do) with a fine tip: https://amzn.to/2GaENlN NOTE: I've been using this one for about a year with no issues. The heat gun is AWESOME for hot air/solder paste construction. The iron works well for traditional soldering. - Electronics Tweezer Set: https://amzn.to/2ENy00w Please share your builds with me when you're done, and tell us about how it works out for you in the comments below. Thanks! de K6ARK