{"id":19,"date":"2026-10-28T00:05:27","date_gmt":"2026-10-28T00:05:27","guid":{"rendered":"https:\/\/k0axx.net\/?page_id=19"},"modified":"2026-10-28T00:05:27","modified_gmt":"2026-10-28T00:05:27","slug":"vhf-propagation-modes","status":"publish","type":"page","link":"https:\/\/k0axx.net\/?page_id=19","title":{"rendered":"VHF\/UHF Propagation Modes Explained"},"content":{"rendered":"<p class=\"k-kicker wp-block-paragraph\">TECHNICAL NOTE \/ PROPAGATION<\/p><h2 class=\"wp-block-heading\">Sporadic-E<\/h2><p class=\"wp-block-paragraph\">Sporadic-E can support very long 50 MHz contacts when ionized E-region patches form. Openings can shift rapidly in distance and bearing. Higher frequencies sometimes benefit under strong conditions, but success on 6 meters is not proof of a 2-meter opening.<\/p><h2 class=\"wp-block-heading\">Meteor scatter<\/h2><p class=\"wp-block-paragraph\">Meteor trails can create brief, rapidly changing reflections, particularly useful around 50 and 144 MHz. Fast digital protocols such as MSK144 are designed for bursty conditions. A path may be workable by meteor scatter when normal tropospheric service is not.<\/p><h2 class=\"wp-block-heading\">Tropospheric enhancement<\/h2><p class=\"wp-block-paragraph\">Temperature and humidity gradients influence refractivity. Stable inversions can favor unusually long VHF\/UHF paths, but a local barometer reading cannot establish that a duct spans the full route.<\/p><h2 class=\"wp-block-heading\">EME \/ Moonbounce<\/h2><p class=\"wp-block-paragraph\">Earth\u2013Moon\u2013Earth links face very large path loss and require careful accounting of antenna gain, receiver noise, pointing and lunar visibility. The apparent lunar disk is roughly half a degree across; broad antenna beamwidth does not eliminate large two-way path loss.<\/p><h2 class=\"wp-block-heading\">Modes and evidence<\/h2><p class=\"wp-block-paragraph\">CW\/SSB reports, FT8\/Q65 decoding, beacons and validated on-air exchanges each add different evidence. Compare frequency, exact UTC time, polarization and geographic path before attributing a contact to a propagation mechanism.<\/p>","protected":false},"excerpt":{"rendered":"<p>Sporadic-E, meteor scatter, tropospheric enhancement and EME explained for practical amateurs.<\/p>\n","protected":false},"author":1,"featured_media":0,"parent":0,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"","meta":{"footnotes":""},"class_list":["post-19","page","type-page","status-publish","hentry"],"_links":{"self":[{"href":"https:\/\/k0axx.net\/index.php?rest_route=\/wp\/v2\/pages\/19","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/k0axx.net\/index.php?rest_route=\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/k0axx.net\/index.php?rest_route=\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/k0axx.net\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/k0axx.net\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=19"}],"version-history":[{"count":0,"href":"https:\/\/k0axx.net\/index.php?rest_route=\/wp\/v2\/pages\/19\/revisions"}],"wp:attachment":[{"href":"https:\/\/k0axx.net\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=19"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}