Notes concerning “Radio”

• Can you do direct digital synthesis (DDS) at over a gigahertz? 02021-02-08 (updated 02021-02-24) (30 minutes)
• A bargain-basement Holter monitor with a BOM under US$2.50 02021-04-07 (updated 02021-07-27) (33 minutes)
• Flux-gate downconversion in a loopstick antenna? 02021-06-15 (updated 02021-07-27) (2 minutes)