I Need Help - AI Part 2302

Prompt: I bought a spool of tiny PTFE tubing by mistake. It's about the same diameter as 18 or 20 gauge wire. It would work as a spacer. I also have some 20 gauge enameled wire and a lot of 22 gauge silicone insulated wire. I'm not hooked on the 28. I have 12 and 16 gauge PVC wire (plain old house wiring). Suggestions? Using insulated would simplify winding.

Switching to the 22 AWG silicone-insulated wire is the best move for this build. You are completely right that using insulated wire simplifies the process, but more importantly, it solves the high-frequency capacitance problem automatically.

Here is how your available materials stack up for a Band 2–6 HF coil:

## 1. The Winner: 22 AWG Silicone Insulated

The silicone jacket acts as a perfect, built-in dielectric spacer. By winding the insulated wire tightly against itself, the copper conductors inside remain physically separated by twice the thickness of the insulation.

• The Benefit: This naturally drops the inter-turn capacitance without the tedious process of dual-winding a spacer, making it ideal for the 42 MHz top end of Band 6. It is also extremely flexible, making it easy to create the tap loops for your plug-board junctions. * The Constraint: You need to check the outer diameter (OD) of the insulation. If you need roughly 80 to 100 turns for Band 2, and you have a strict 5-inch winding window, the total wire OD cannot exceed 0.05 inches (1.27 mm). If the silicone is exceptionally thick, you will run out of space on the form.

## 2. The Backup: 20 AWG Enameled + PTFE Tubing

If the silicone wire is too fat to fit the required turns in 5 inches, use the 20 AWG enameled wire and wind the PTFE tubing alongside it as a physical spacer.

• The Benefit: You get exact spacing control. PTFE (Teflon) has phenomenal RF dielectric properties. You do not even need to unwind the tubing afterward; simply leave it permanently coiled between the copper turns. * The Constraint: Winding two strands tightly at the same time requires a bit more patience and tension control to keep the coil uniform.

## 3. The Upgrade: Skin Effect

Ditching the 28 AWG wire for 20 or 22 AWG is a massive electrical upgrade for Bands 4, 5, and 6. As frequencies climb into the MHz range, RF current stops flowing through the core of the wire and rides exclusively on the outside surface — a phenomenon called the skin effect. The thicker 20/22 AWG wire provides significantly more surface area, lowering the resistance and raising the "Q" (efficiency) of the coil.

## 4. Skip the House Wire

Leave the 12 and 16 AWG solid PVC house wiring on the spool. It is far too stiff to cleanly wrap around a 1/2-inch PVC form. Trying to force it into a 5-inch tight wrap will likely deform the pipe or create irregular, springing coils that make consistent tuning impossible.

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Last modified: Wednesday, 29 Jul 2026