{"id":3126,"date":"2012-11-14T17:14:30","date_gmt":"2012-11-14T23:14:30","guid":{"rendered":"http:\/\/w0ep.us\/OM\/?p=3126"},"modified":"2012-11-14T17:17:10","modified_gmt":"2012-11-14T23:17:10","slug":"more-gpsdo","status":"publish","type":"post","link":"http:\/\/w0ep.us\/OM\/?p=3126","title":{"rendered":"More GPSDO"},"content":{"rendered":"<p>[Today&#8217;s run: white house &#8211; 3 miles]<\/p>\n<p>My GPSDO has been running since summer and I&#8217;ve noticed a problem with it.\u00a0 It will go fine for about a week, maybe less, then it will start to slow down.\u00a0 The change accelerates and eventually I get to the negative voltage rail for the frequency control.\u00a0 That&#8217;s no good.\u00a0 I have it do this cycle at least twice now, I don&#8217;t remember.<\/p>\n<p>I have tried two different fixes so far.\u00a0 First, I thought maybe the oscillator was seeing a varying output impedance so I changed out the very small 50 Ohm output resistor for a quarter-watt job.<\/p>\n<p>That didn&#8217;t fix the problem.\u00a0 So now I have added some shielding on the 10 Mhz output line and I&#8217;m running with that to see what happens.<\/p>\n<p>I have also ordered another line-buffer IC which is the gizmo that processes the signal coming from the oscillator.\u00a0 Between that resistor and the line-buffer, I still wonder if something in the output circuit is causing the oscillator to see a changing impedance.<\/p>\n<p><a href=\"http:\/\/w0ep.us\/OM\/?attachment_id=3129\" rel=\"attachment wp-att-3129\"><img loading=\"lazy\" decoding=\"async\" class=\"alignleft size-medium wp-image-3129\" title=\"IMG00701-20121108-0929\" src=\"http:\/\/w0ep.us\/OM\/wp-content\/uploads\/2012\/11\/IMG00701-20121108-0929-700x525.jpg\" alt=\"\" width=\"700\" height=\"525\" srcset=\"http:\/\/w0ep.us\/OM\/wp-content\/uploads\/2012\/11\/IMG00701-20121108-0929-700x525.jpg 700w, http:\/\/w0ep.us\/OM\/wp-content\/uploads\/2012\/11\/IMG00701-20121108-0929.jpg 1024w\" sizes=\"auto, (max-width: 700px) 100vw, 700px\" \/><\/a><\/p>\n","protected":false},"excerpt":{"rendered":"<p>[Today&#8217;s run: white house &#8211; 3 miles] My GPSDO has been running since summer and I&#8217;ve noticed a problem with it.\u00a0 It will go fine for about a week, maybe less, then it will start to slow down.\u00a0 The change accelerates and eventually I get to the negative voltage rail for the frequency control.\u00a0 That&#8217;s [&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-3126","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\/3126","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=3126"}],"version-history":[{"count":3,"href":"http:\/\/w0ep.us\/OM\/index.php?rest_route=\/wp\/v2\/posts\/3126\/revisions"}],"predecessor-version":[{"id":3128,"href":"http:\/\/w0ep.us\/OM\/index.php?rest_route=\/wp\/v2\/posts\/3126\/revisions\/3128"}],"wp:attachment":[{"href":"http:\/\/w0ep.us\/OM\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=3126"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/w0ep.us\/OM\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=3126"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/w0ep.us\/OM\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=3126"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}