{"id":2213,"date":"2012-02-23T17:38:51","date_gmt":"2012-02-23T23:38:51","guid":{"rendered":"http:\/\/w0ep.us\/OM\/?p=2213"},"modified":"2012-02-23T17:40:02","modified_gmt":"2012-02-23T23:40:02","slug":"toward-the-finish-of-the-gpsdo-project","status":"publish","type":"post","link":"http:\/\/w0ep.us\/OM\/?p=2213","title":{"rendered":"Toward the finish of the GPSDO project"},"content":{"rendered":"

[Today’s run: Watson Road]<\/p>\n

I think I am getting down toward the finish of my GPSDO project.\u00a0 I need to do a bit of tuning.\u00a0 And, I need to eventually change the way my GPS antenna is attaching.\u00a0 Otherwise I think it is complete enough for the time being.<\/p>\n

I started out with a chassis that had been some sort of heater controller unit.\u00a0 I was hoping I could use the existing +\/- power supply for my control voltage source.\u00a0 But that supply failed when I started integrating all the parts.\u00a0 So I built a different +\/- 5 VDC supply to replace it.<\/p>\n

I also replaced my\u00a0 +12\/+5\/+3.3 regulator board because my 3-pin regulators were getting very hot.\u00a0 I measured the current to that supply at 0.5 A.\u00a0 I also reconfigured it so that the +5\/+3.3 are downstream from the +12 regulator.\u00a0 I put a big heat sink on that +12 regulator.\u00a0 It is still getting hot, but I think I’ve improved the situation.<\/p>\n

I’ve built at least 7 circuit boards for this project using the toner-transfer method.\u00a0 I’m getting better at it.\u00a0 One improvement is that I now upsize the traces and pads in EagleCad.\u00a0 There’s no reason to use hair-thin traces when all my parts are through-hole stuff and I’m working on power supply circuits.<\/p>\n

I have had the GPSDO working and up to operating temp at least three times now.\u00a0 I want to get back to that spot and adjust the rough-tune so that my control voltage is as near to zero as I can get it.\u00a0 My previous runs have shown it having a frequency accuracy of around 0.001 Hz over a long term.\u00a0 Over the short term it is more like 0.1 Hz.\u00a0 That still beats anything else I’ve got.<\/p>\n

(The green light on the front means it is “locked” to the GPS.)<\/p>\n

\"\"<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"

[Today’s run: Watson Road] I think I am getting down toward the finish of my GPSDO project.\u00a0 I need to do a bit of tuning.\u00a0 And, I need to eventually change the way my GPS antenna is attaching.\u00a0 Otherwise I think it is complete enough for the time being. I started out with a chassis […]<\/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-2213","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\/2213","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=2213"}],"version-history":[{"count":6,"href":"http:\/\/w0ep.us\/OM\/index.php?rest_route=\/wp\/v2\/posts\/2213\/revisions"}],"predecessor-version":[{"id":2220,"href":"http:\/\/w0ep.us\/OM\/index.php?rest_route=\/wp\/v2\/posts\/2213\/revisions\/2220"}],"wp:attachment":[{"href":"http:\/\/w0ep.us\/OM\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=2213"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/w0ep.us\/OM\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=2213"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/w0ep.us\/OM\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=2213"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}