{"query": "Shortwave (HF) — around the world on the ionosphere's mirror", "count": 2, "results": [{"id": "card_n_a735e61f7ca1", "title": "Shortwave (HF) — around the world on the ionosphere's mirror", "shelf": "science", "surface": "secular", "snippet": "3–30 MHz; the 19 m band's wavelength seals at 15 MHz: https://narrowhighway.com/s/d6211f4efb2518c6de145decf57f27b131a01c24ce7841853f395b7bc986c323 . Here the ionosphere's\nF-layer refracts waves back t", "authority_tier": "engine_derived", "source": "Concordance assay — 2026-07-09", "generated": false}, {"id": "card_n_ba6d9264fa3c", "title": "AM broadcast (medium wave) — where the dial begins", "shelf": "science", "surface": "secular", "snippet": "530–1700 kHz; sealed wavelengths 565 m down to 176 m: https://narrowhighway.com/s/d6211f4efb2518c6de145decf57f27b131a01c24ce7841853f395b7bc986c323 . The waves are so long\nthat the TOWER is the antenna", "authority_tier": "engine_derived", "source": "Concordance assay — 2026-07-09", "generated": false}]}