Living collection of notes on the topic of amateur radio.

Operations

Propagation conditions

• dr2w.de DX
• hf.dxview.org

Special events

• Parks on the Air
• Summits on the Air
• SOTA Atlas

Exam prep

This section covers the Polish ham radio license exams.

• egzaminKF.pl – exam questions, tests, topic-focused guides.
• Anki deck – Pytanie Egzaminacyjne Klasa A (by SP9TEM)

Radio theory

• lcamtuf – Radios, how do they work?
• Superheterodyne receivers (PL 🇵🇱) – dr inż. Wojciech Kazubski, Politechnika Warszawska

CW (morse code)

• LCWO — Online CW learning site.

Digital

• SQ9JDO — personal page of Andrzej, the Polish DMR mastermind.
• HamTetra — all about Tetra for amateur radio ops.
• M17 — free and open-source digital radio protocol for voice and data.

Radiosondes

• Hot air baloon lift calculator (SP9UNB).

Antenna building

• ¼ wave GP antenna
• Coax cable signal loss
• SimNEC — RF circuit analysis
• NanoVNA
  • nanovna-saver — dumping data from NanoVNA
  • AntScope2 — VNA data analysis
• Chokes
  • Common-mode choke impedances (G3TXQ)