{"id":4523,"date":"2014-09-22T20:23:11","date_gmt":"2014-09-23T01:23:11","guid":{"rendered":"http:\/\/w0ep.us\/OM\/?p=4523"},"modified":"2014-09-22T20:23:11","modified_gmt":"2014-09-23T01:23:11","slug":"antenna-work","status":"publish","type":"post","link":"http:\/\/w0ep.us\/OM\/?p=4523","title":{"rendered":"Antenna work"},"content":{"rendered":"

[today’s run: 3.4 miles]<\/p>\n

I have not been making much progress on the radio station project in September.<\/p>\n

Over the weekend I did start a technical project: build a transmitting antenna.<\/p>\n

We want omni-directional, horizontal polarization.<\/p>\n

Using information in my ARRL Antenna Book, I built a small transmitting loop out of 1\/2 copper water pipe.\u00a0\u00a0\u00a0 I used the specifications from a web page tool<\/a> which will calculate small loop antenna designs.\u00a0 The design has to have a small amount of capacitance to tune it to the right frequency.\u00a0 I used a “trombone” capacitor made from 1\/4″ copper pipe inside the 1\/2″ copper pipe.<\/p>\n

The first thing I noticed from this design is that it needs more physical robustness to avoid moving in such a way as to detune it from the design frequency.\u00a0 That’s not good.<\/p>\n

So I have a second idea which I have not yet been able to try: replace the trombone capacitor with a piece of double sided copper circuit board material, about 1 square inch in size and solder to both sides.\u00a0 Then I can use some tin snips and a file to tune it.<\/p>\n

I also need to figure out mounting and feeding it.<\/p>\n

The thing is a nice little loop about the size of a dinner plate.\u00a0 If I can make it work it will save us a few hundred dollars.<\/p>\n","protected":false},"excerpt":{"rendered":"

[today’s run: 3.4 miles] I have not been making much progress on the radio station project in September. Over the weekend I did start a technical project: build a transmitting antenna. We want omni-directional, horizontal polarization. Using information in my ARRL Antenna Book, I built a small transmitting loop out of 1\/2 copper water pipe.\u00a0\u00a0\u00a0 […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[13,5],"tags":[],"class_list":["post-4523","post","type-post","status-publish","format-standard","hentry","category-classic-book-radio","category-ham-radio"],"_links":{"self":[{"href":"http:\/\/w0ep.us\/OM\/index.php?rest_route=\/wp\/v2\/posts\/4523","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=4523"}],"version-history":[{"count":1,"href":"http:\/\/w0ep.us\/OM\/index.php?rest_route=\/wp\/v2\/posts\/4523\/revisions"}],"predecessor-version":[{"id":4524,"href":"http:\/\/w0ep.us\/OM\/index.php?rest_route=\/wp\/v2\/posts\/4523\/revisions\/4524"}],"wp:attachment":[{"href":"http:\/\/w0ep.us\/OM\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=4523"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/w0ep.us\/OM\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=4523"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/w0ep.us\/OM\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=4523"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}