{"version":"1.0","provider_name":"Johnson&#039;s Techworld","provider_url":"https:\/\/johnsonfrancis.org\/techworld","author_name":"Johnson Francis","author_url":"https:\/\/johnsonfrancis.org\/techworld\/author\/jf\/","title":"Comparing Submarine Communication Systems: ELF vs VLF - Johnson&#039;s Techworld","type":"rich","width":600,"height":338,"html":"<blockquote class=\"wp-embedded-content\" data-secret=\"PkIeKAnPih\"><a href=\"https:\/\/johnsonfrancis.org\/techworld\/comparing-submarine-communication-systems-elf-vs-vlf\/\">Comparing Submarine Communication Systems: ELF vs VLF<\/a><\/blockquote><iframe sandbox=\"allow-scripts\" security=\"restricted\" src=\"https:\/\/johnsonfrancis.org\/techworld\/comparing-submarine-communication-systems-elf-vs-vlf\/embed\/#?secret=PkIeKAnPih\" width=\"600\" height=\"338\" title=\"&#8220;Comparing Submarine Communication Systems: ELF vs VLF&#8221; &#8212; Johnson&#039;s Techworld\" data-secret=\"PkIeKAnPih\" frameborder=\"0\" marginwidth=\"0\" marginheight=\"0\" scrolling=\"no\" class=\"wp-embedded-content\"><\/iframe><script>\n\/*! This file is auto-generated *\/\n!function(d,l){\"use strict\";l.querySelector&&d.addEventListener&&\"undefined\"!=typeof URL&&(d.wp=d.wp||{},d.wp.receiveEmbedMessage||(d.wp.receiveEmbedMessage=function(e){var t=e.data;if((t||t.secret||t.message||t.value)&&!\/[^a-zA-Z0-9]\/.test(t.secret)){for(var s,r,n,a=l.querySelectorAll('iframe[data-secret=\"'+t.secret+'\"]'),o=l.querySelectorAll('blockquote[data-secret=\"'+t.secret+'\"]'),c=new RegExp(\"^https?:$\",\"i\"),i=0;i<o.length;i++)o[i].style.display=\"none\";for(i=0;i<a.length;i++)s=a[i],e.source===s.contentWindow&&(s.removeAttribute(\"style\"),\"height\"===t.message?(1e3<(r=parseInt(t.value,10))?r=1e3:~~r<200&&(r=200),s.height=r):\"link\"===t.message&&(r=new URL(s.getAttribute(\"src\")),n=new URL(t.value),c.test(n.protocol))&&n.host===r.host&&l.activeElement===s&&(d.top.location.href=t.value))}},d.addEventListener(\"message\",d.wp.receiveEmbedMessage,!1),l.addEventListener(\"DOMContentLoaded\",function(){for(var e,t,s=l.querySelectorAll(\"iframe.wp-embedded-content\"),r=0;r<s.length;r++)(t=(e=s[r]).getAttribute(\"data-secret\"))||(t=Math.random().toString(36).substring(2,12),e.src+=\"#?secret=\"+t,e.setAttribute(\"data-secret\",t)),e.contentWindow.postMessage({message:\"ready\",secret:t},\"*\")},!1)))}(window,document);\n\/\/# sourceURL=https:\/\/johnsonfrancis.org\/techworld\/wp-includes\/js\/wp-embed.min.js\n<\/script>\n","thumbnail_url":"https:\/\/johnsonfrancis.org\/techworld\/wp-content\/uploads\/2026\/07\/Comparing-Submarine-Communication-Systems-ELF-vs-VLF.jpg","thumbnail_width":1268,"thumbnail_height":712,"description":"While both Extremely Low Frequency (ELF) and Very Low Frequency (VLF) systems are designed to overcome the barrier that seawater presents to standard radio waves, they operate on different scales and serve completely different tactical purposes for submarine fleets. Here is how VLF (operating between 3 kHz and 30 kHz) compares to ELF (operating between [&hellip;]"}