<unk> awọn wavelengths osise pin si awọn amateurs ni Oṣu Kẹwa ati ki o kere wavelengths; sibẹsibẹ, amateurs won ni opin nipa ilana si wavelengths gun ju 150 mita (2 MHz). A diẹ orire amateurs ti o gba pataki igbanilaaye fun igbeyewo awọn ibaraẹnisọrọ ni wavelengths kuru ju 150 mita pari ogogorun ti gun ijinna ọna meji awọn olubasọrọ lori 100 mita (3 MHz) ni 1923 pẹlu awọn akọkọ transatlantic ọna meji awọn olubasọrọ. nipa 1924 ọpọlọpọ awọn afikun pataki iwe-aṣẹ amateurs won routinely ṣiṣe transoceanic olubasọrọ ni ijinna ti 6,000 miles (9,600 km) ati siwaju sii. lori 21 September 1924 orisirisi awọn amateurs ni california pari meji-ọna olubasọrọ pẹlu kan amateur ni October. lori 19 October ni New Zealand ati lori 25 November ni New Zealand. awọn United States ati awọn United States ti a ti ṣe ni ayika awọn 80 mita ọna meji olubasọrọ ni ayika ayika 90 mita band (14 MHz). lori awọn kẹta International Radio Conference (Ohun ti a ti a ti a ti fi fun ni idaji-ọna ọna) bi ọpọlọpọ awọn igba ni
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