1.0SADARS: Shefford and District Amateur Radio Societyhttps://sadars.co.uk/wprich600338<blockquote class="wp-embedded-content" data-secret="OSWrVRfBtB"><a href="https://sadars.co.uk/wp/archives/910">16 April 2015 – THE AGE OF SPARK WIRELESS BY BRIAN HAWES, G2KQ</a></blockquote><iframe sandbox="allow-scripts" security="restricted" src="https://sadars.co.uk/wp/archives/910/embed#?secret=OSWrVRfBtB" width="600" height="338" title="“16 April 2015 – THE AGE OF SPARK WIRELESS BY BRIAN HAWES, G2KQ” — SADARS: Shefford and District Amateur Radio Society" data-secret="OSWrVRfBtB" frameborder="0" marginwidth="0" marginheight="0" scrolling="no" class="wp-embedded-content"></iframe><script> /*! This file is auto-generated */ !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); //# sourceURL=https://sadars.co.uk/wp/wp-includes/js/wp-embed.min.js </script> Brian started by explaining that many persons contributed to the inventions which led to the start of the wireless age. Mentioned were famous names, such as Clark Maxwell, Heinrich Hertz and Edouard Branly. It was Branly’s invention of the coherer that was used in all early detection of radio waves. In 1894 Prof. Oliver Lodge … Continue reading →http://sadars.co.uk/wp/wp-content/uploads/2015/04/two-up.jpg