{"id":310,"date":"2020-09-22T12:58:53","date_gmt":"2020-09-22T12:58:53","guid":{"rendered":"https:\/\/maritimesa.org\/nautical-science-grade-12\/?p=310"},"modified":"2020-09-22T17:41:53","modified_gmt":"2020-09-22T17:41:53","slug":"radio-direction-finding-system-marine-radio-beacons","status":"publish","type":"post","link":"https:\/\/maritimesa.org\/nautical-science-grade-12\/2020\/09\/22\/radio-direction-finding-system-marine-radio-beacons\/","title":{"rendered":"Radio direction finding system (marine radio beacons)"},"content":{"rendered":"<p>One of the systems which were used along the Namibian and South African coasts was a series of marine radio beacons situated along the coastline and which provided vessels navigating in our waters with a means of obtaining radio bearings. Six of these stations were situated in Namibia and twenty four in South Africa.<br \/>\nThe system operated in the MF (medium frequency) band (280 \u2013 315 KHz) and had a range of between 25 and 100 nautical miles. Since the bearings obtained were great circle bearings, they had to be corrected for convergency before they could be plotted on a Mercator chart. The systems two main shortcomings were:<\/p>\n<ul>\n<li>The signal was prone to distortion when it passed over the coastline. Radio waves travel more slowly over land than over the sea.<\/li>\n<li>At night the sky waves interfere with the ground waves, causing fading when the two signals are received simultaneously. The sky waves also cause bearing errors.<\/li>\n<\/ul>\n<div id=\"attachment_146\" style=\"width: 910px\" class=\"wp-caption alignnone\"><img loading=\"lazy\" decoding=\"async\" aria-describedby=\"caption-attachment-146\" class=\"wp-image-146 size-full\" src=\"https:\/\/maritimesa.org\/nautical-science-grade-12\/wp-content\/uploads\/sites\/7\/2020\/09\/12-1-4-10-fig1.jpg\" alt=\"\" width=\"900\" height=\"742\" srcset=\"https:\/\/maritimesa.org\/nautical-science-grade-12\/wp-content\/uploads\/sites\/7\/2020\/09\/12-1-4-10-fig1.jpg 900w, https:\/\/maritimesa.org\/nautical-science-grade-12\/wp-content\/uploads\/sites\/7\/2020\/09\/12-1-4-10-fig1-300x247.jpg 300w, https:\/\/maritimesa.org\/nautical-science-grade-12\/wp-content\/uploads\/sites\/7\/2020\/09\/12-1-4-10-fig1-768x633.jpg 768w, https:\/\/maritimesa.org\/nautical-science-grade-12\/wp-content\/uploads\/sites\/7\/2020\/09\/12-1-4-10-fig1-177x146.jpg 177w, https:\/\/maritimesa.org\/nautical-science-grade-12\/wp-content\/uploads\/sites\/7\/2020\/09\/12-1-4-10-fig1-50x41.jpg 50w, https:\/\/maritimesa.org\/nautical-science-grade-12\/wp-content\/uploads\/sites\/7\/2020\/09\/12-1-4-10-fig1-91x75.jpg 91w\" sizes=\"(max-width: 900px) 100vw, 900px\" \/><p id=\"caption-attachment-146\" class=\"wp-caption-text\"><strong>The distribution of radio beacons and radar transponders was as indicated above.<\/strong><\/p><\/div>\n","protected":false},"excerpt":{"rendered":"<p>One of the systems which were used along the Namibian and South African coasts was a series of marine radio beacons situated along the coastline and which provided vessels navigating in our waters with a means of obtaining radio bearings. Six of these stations were situated in Namibia and twenty [&hellip;]<\/p>\n","protected":false},"author":6,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[24,34],"tags":[],"class_list":["post-310","post","type-post","status-publish","format-standard","hentry","category-12-1-4-electronic-navigation-systems","category-12-1-4-10-radio-direction-finding-system-marine-radio-beacons"],"_links":{"self":[{"href":"https:\/\/maritimesa.org\/nautical-science-grade-12\/wp-json\/wp\/v2\/posts\/310"}],"collection":[{"href":"https:\/\/maritimesa.org\/nautical-science-grade-12\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/maritimesa.org\/nautical-science-grade-12\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/maritimesa.org\/nautical-science-grade-12\/wp-json\/wp\/v2\/users\/6"}],"replies":[{"embeddable":true,"href":"https:\/\/maritimesa.org\/nautical-science-grade-12\/wp-json\/wp\/v2\/comments?post=310"}],"version-history":[{"count":4,"href":"https:\/\/maritimesa.org\/nautical-science-grade-12\/wp-json\/wp\/v2\/posts\/310\/revisions"}],"predecessor-version":[{"id":358,"href":"https:\/\/maritimesa.org\/nautical-science-grade-12\/wp-json\/wp\/v2\/posts\/310\/revisions\/358"}],"wp:attachment":[{"href":"https:\/\/maritimesa.org\/nautical-science-grade-12\/wp-json\/wp\/v2\/media?parent=310"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/maritimesa.org\/nautical-science-grade-12\/wp-json\/wp\/v2\/categories?post=310"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/maritimesa.org\/nautical-science-grade-12\/wp-json\/wp\/v2\/tags?post=310"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}