{"id":3452,"date":"2013-03-27T21:10:13","date_gmt":"2013-03-28T02:10:13","guid":{"rendered":"http:\/\/w0ep.us\/OM\/?p=3452"},"modified":"2013-03-27T21:10:13","modified_gmt":"2013-03-28T02:10:13","slug":"40-db-tap-by-n5ese","status":"publish","type":"post","link":"http:\/\/w0ep.us\/OM\/?p=3452","title":{"rendered":"-40 db tap (by N5ESE)"},"content":{"rendered":"<p>[Today&#8217;s run: Schafers Chapel 5 miles]<\/p>\n<p>Now that I have a really cool power meter, I need a device that will let me measure larger quantities.<\/p>\n<p>The power meter I built goes way down to somewhere around -70 dbm.\u00a0 That is a very small signal.\u00a0 And it goes up to around +10 dbm.\u00a0 That&#8217;s a range of about\u00a0 100 picowatts to 10 milliwatts.\u00a0 It is a big range but heavy toward the little-bitty end of the scale.<\/p>\n<p>So what an intrepid guy does is do a google search for a &#8220;tap&#8221;.\u00a0 In this case<a title=\"N5ESE 40 db tap attenuator\" href=\"http:\/\/www.n5ese.com\/tap_atten.htm\"> I found a great web page for a -40 db tap<\/a>.\u00a0 Which means that it taps off\u00a0 a very small portion of the real signal and sends that small portion to the meter.\u00a0 The rest continues on to the dummy load or the antenna or wherever it is going.\u00a0 The small portion is 1\/10,000th of the power of the total signal.\u00a0 That will let me then measure from -30 dbm to +50 dbm (100 watts).<\/p>\n<p>He uses a short length of copper pipe and puts the parts inside with two pipe-end plugs and a bnc connector on each end.<\/p>\n<p>When you get into building radio things sometimes the shape of the thing has significance in how it works.\u00a0 I don&#8217;t know how much that is true in this case, but having the cylindrical shape probably does help it work better.\u00a0 And it is completely enclosed in copper pipe.\u00a0 That is good.<\/p>\n<p>Unfortunately, Lowes doesn&#8217;t carry that kind of end plug.\u00a0 So I have some more shopping to do to find that.<\/p>\n<p>Add it to the project list!<\/p>\n","protected":false},"excerpt":{"rendered":"<p>[Today&#8217;s run: Schafers Chapel 5 miles] Now that I have a really cool power meter, I need a device that will let me measure larger quantities. The power meter I built goes way down to somewhere around -70 dbm.\u00a0 That is a very small signal.\u00a0 And it goes up to around +10 dbm.\u00a0 That&#8217;s a [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[5],"tags":[],"class_list":["post-3452","post","type-post","status-publish","format-standard","hentry","category-ham-radio"],"_links":{"self":[{"href":"http:\/\/w0ep.us\/OM\/index.php?rest_route=\/wp\/v2\/posts\/3452","targetHints":{"allow":["GET"]}}],"collection":[{"href":"http:\/\/w0ep.us\/OM\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/w0ep.us\/OM\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/w0ep.us\/OM\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/w0ep.us\/OM\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=3452"}],"version-history":[{"count":1,"href":"http:\/\/w0ep.us\/OM\/index.php?rest_route=\/wp\/v2\/posts\/3452\/revisions"}],"predecessor-version":[{"id":3453,"href":"http:\/\/w0ep.us\/OM\/index.php?rest_route=\/wp\/v2\/posts\/3452\/revisions\/3453"}],"wp:attachment":[{"href":"http:\/\/w0ep.us\/OM\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=3452"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/w0ep.us\/OM\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=3452"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/w0ep.us\/OM\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=3452"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}