The low-power radio reference, built by homebrewers.

Calculators, core data, and build notes for homebrew QRP operators.

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Tool. Coordinates, addresses and locators, with the cell on the map.

Tool. Ferrite baluns and transmission-line transformers, 1:1 to 9:1.

Tool. Crystal ladder filters from your measured crystals.

Reference. E6 to E96 series, color codes, SMD codes and dielectrics.

Reference. Copper magnet wire #10 to #40 AWG: size, resistance, turns per inch.

Circuits. Nine sourced circuits with schematics, BOMs and ngspice simulations.