{"id":1474,"date":"2010-11-05T21:49:59","date_gmt":"2010-11-06T02:49:59","guid":{"rendered":"http:\/\/www.summet.com\/blog\/?p=1474"},"modified":"2010-11-05T21:59:47","modified_gmt":"2010-11-06T02:59:47","slug":"building-an-ota-hdtv-antenna","status":"publish","type":"post","link":"https:\/\/www.summet.com\/blog\/2010\/11\/05\/building-an-ota-hdtv-antenna\/","title":{"rendered":"Building an OTA HDTV Antenna"},"content":{"rendered":"<div class='__iawmlf-post-loop-links' style='display:none;' data-iawmlf-post-links='[{&quot;id&quot;:566,&quot;href&quot;:&quot;http:\\\/\\\/blog.makezine.com\\\/archive\\\/2009\\\/01\\\/maker_workshop_pdf_dtv_antenna.html&quot;,&quot;archived_href&quot;:&quot;&quot;,&quot;redirect_href&quot;:&quot;http:\\\/\\\/makezine.com\\\/archive\\\/2009\\\/01\\\/maker_workshop_pdf_dtv_antenna.html&quot;,&quot;checks&quot;:[],&quot;broken&quot;:false,&quot;last_checked&quot;:null,&quot;process&quot;:&quot;done&quot;}]'><\/div>\n<p><a href=\"http:\/\/www.summet.com\/blog\/wp-content\/uploads\/2010\/11\/screws_washers.jpg\"><img loading=\"lazy\" decoding=\"async\" src=\"http:\/\/www.summet.com\/blog\/wp-content\/uploads\/2010\/11\/screws_washers-225x300.jpg\" alt=\"Screws and Washers holding coat hanger parts to the board\" title=\"Screws and Washers holding coat hanger parts to the board\" width=\"225\" height=\"300\" class=\"alignleft size-medium wp-image-1531\" srcset=\"https:\/\/www.summet.com\/blog\/wp-content\/uploads\/2010\/11\/screws_washers-225x300.jpg 225w, https:\/\/www.summet.com\/blog\/wp-content\/uploads\/2010\/11\/screws_washers-768x1024.jpg 768w, https:\/\/www.summet.com\/blog\/wp-content\/uploads\/2010\/11\/screws_washers.jpg 900w\" sizes=\"auto, (max-width: 225px) 100vw, 225px\" \/><\/a><br \/>\nThis week I built a TV antenna. Previously, we had been using a commercially purchased Radio Shack antenna with a built in pre-amplifier, but we left it mounted on the (tall, exterior) wall of our previous house. We had planned on purchasing a new antenna to place in our attic when I found plans on the Internet for how to make your own out of coat hangers and scrap wood. (Really, what CAN&#8217;T you find plans for on the Internet?)<!--more--><\/p>\n<p>Located in Metro Atlanta, I am lucky to be able to pick up <a href=\"http:\/\/www.summet.com\/blog\/2007\/09\/03\/listing-of-atlantadecatur-high-quality-digital-ota-channels\/\"> quite a few<\/a> HDTV stations using the small Radio Shack antenna.<br \/>\nMy home-built antenna is larger and less aesthetically pleasing, but it does have the benefit of not needing a power injector (for the pre-amplifier) and pulling in some stations that we couldn&#8217;t receive before. Plus, it cost $2.92 for a 300 to 75 ohm transformer that I bought with a pair of rabbit ears at a thrift shop, plus a lot of scrap parts I found in the garage and my wife&#8217;s closet. (If I do all the laundry she runs out of coat hangers&#8230;)<\/p>\n<p><a href=\"http:\/\/www.summet.com\/blog\/wp-content\/uploads\/2010\/11\/coathanger_wires.jpg\"><img loading=\"lazy\" decoding=\"async\" src=\"http:\/\/www.summet.com\/blog\/wp-content\/uploads\/2010\/11\/coathanger_wires-300x225.jpg\" alt=\"The coat hanger wires all cut and laid out.\" title=\"coat hanger wires\" width=\"300\" height=\"225\" class=\"alignleft size-medium wp-image-1532\" srcset=\"https:\/\/www.summet.com\/blog\/wp-content\/uploads\/2010\/11\/coathanger_wires-300x225.jpg 300w, https:\/\/www.summet.com\/blog\/wp-content\/uploads\/2010\/11\/coathanger_wires-1024x768.jpg 1024w, https:\/\/www.summet.com\/blog\/wp-content\/uploads\/2010\/11\/coathanger_wires.jpg 1200w\" sizes=\"auto, (max-width: 300px) 100vw, 300px\" \/><\/a><br \/>\nI cut the metal coat hangers into V&#8217;s where the leg of each V is 8&#8243; long and bent them so that the tips of the V&#8217;s are 3&#8243; apart.  Horizontally, the points of the V&#8217;s are separated by 2&#8243;. Vertically, each V is mounted 5 and 3\/4&#8243; apart. Then I sanded the enamel off of the steel at the connection points so that they would make electrical contact and just screwed them down with big washers. (I tested with a multi-meter, zero ohms at each connection!) I used heat shrink tubing to insulate the upright wire rails from each other when they crossed. The only places I soldered were to connect wires from the center rails to the matching transformer (mounted on the back of the board).<br \/>\n<a href=\"http:\/\/www.summet.com\/blog\/wp-content\/uploads\/2010\/11\/75to300ohmTransformer.jpg\"><img loading=\"lazy\" decoding=\"async\" src=\"http:\/\/www.summet.com\/blog\/wp-content\/uploads\/2010\/11\/75to300ohmTransformer-225x300.jpg\" alt=\"75 to 300 ohm Transformer\" title=\"75 to 300 ohm Transformer\" width=\"225\" height=\"300\" class=\"alignleft size-medium wp-image-1533\" srcset=\"https:\/\/www.summet.com\/blog\/wp-content\/uploads\/2010\/11\/75to300ohmTransformer-225x300.jpg 225w, https:\/\/www.summet.com\/blog\/wp-content\/uploads\/2010\/11\/75to300ohmTransformer-768x1024.jpg 768w, https:\/\/www.summet.com\/blog\/wp-content\/uploads\/2010\/11\/75to300ohmTransformer.jpg 900w\" sizes=\"auto, (max-width: 225px) 100vw, 225px\" \/><\/a><\/p>\n<p> Because my &#8220;in-stock&#8221; wood screws were too long, they stuck out of the back of the board. I eventually used the top two to affix the antenna to a rafter in the attic, so they serve double duty.<br \/>\n<a href=\"http:\/\/www.summet.com\/blog\/wp-content\/uploads\/2010\/11\/attic3_s1.jpg\"><img loading=\"lazy\" decoding=\"async\" src=\"http:\/\/www.summet.com\/blog\/wp-content\/uploads\/2010\/11\/attic3_s1-225x300.jpg\" alt=\"antenna screwed to rafter in attic\" title=\"antenna screwed to rafter in attic\" width=\"225\" height=\"300\" class=\"alignleft size-medium wp-image-1550\" srcset=\"https:\/\/www.summet.com\/blog\/wp-content\/uploads\/2010\/11\/attic3_s1-225x300.jpg 225w, https:\/\/www.summet.com\/blog\/wp-content\/uploads\/2010\/11\/attic3_s1-768x1024.jpg 768w, https:\/\/www.summet.com\/blog\/wp-content\/uploads\/2010\/11\/attic3_s1.jpg 1200w\" sizes=\"auto, (max-width: 225px) 100vw, 225px\" \/><\/a><\/p>\n<p>I was more than happy with the signal quality of this home-built antenna. It easily rivaled my previous small radio shack patch antenna. In addition to the channels I could <a href=\"http:\/\/www.summet.com\/blog\/2007\/09\/03\/listing-of-atlantadecatur-high-quality-digital-ota-channels\/\">previously receive<\/a>, I can now pick up the following additional stations reliably:<\/p>\n<ul>\n<li> 8  (8.1 GPB) 21kW transmitter from Stone Mountain<\/li>\n<li>29 (32.x) APGuide\/Prism\/ThisTV (15kW from Druid Hills site)<\/li>\n<li>35 (53.1) WDTA (1.5kW from the Sun Trust Plaza)<\/li>\n<li>40 (40.1 WIRE) (15kW from WUPA Tower)<\/li>\n<\/ul>\n<p>I found the <a href=\"http:\/\/blog.makezine.com\/archive\/2009\/01\/maker_workshop_pdf_dtv_antenna.html\">instructions<\/a> for this antenna on the Make Blog. I was not impressed with the details of the instructions. They gave a good overview, but some of the measurements and directions were lacking. They say that their wooden board is 3&#8243;x20&#8243;, and that the holes are 1\/2&#8243; in from the outside, but did not actually specify an internal dimension between the two columns of holes. I decided this meant that the holes should be 2&#8243; apart. (My board was not 3&#8243; wide). They also had a random 2&#8243; mark which I interpreted to mean that the top holes started 2&#8243; from the top of the board, and thereafter the sets of holes were to be 5 and 3\/4&#8243; apart. They had a 10&#8243; mark to the &#8220;center&#8221; of the antenna for mounting the wires for the 300 to 75 ohm antenna, but according to my math (2&#8243; + 5 3\/4&#8243;= 7.75&#8243;) and (7.75 &#8211; 10 = 2.25, not 2.875) that isn&#8217;t quite the center distance between a set of holes&#8230;. I just went for the center distance because the text said to mount it in the center. <\/p>\n","protected":false},"excerpt":{"rendered":"<p>This week I built a TV antenna. Previously, we had been using a commercially purchased Radio Shack antenna with a built in pre-amplifier, but we left it mounted on the (tall, exterior) wall of our previous house. We had planned &hellip; <a href=\"https:\/\/www.summet.com\/blog\/2010\/11\/05\/building-an-ota-hdtv-antenna\/\">Continue reading <span class=\"meta-nav\">&rarr;<\/span><\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[13],"tags":[],"class_list":["post-1474","post","type-post","status-publish","format-standard","hentry","category-projects"],"_links":{"self":[{"href":"https:\/\/www.summet.com\/blog\/wp-json\/wp\/v2\/posts\/1474","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.summet.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.summet.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.summet.com\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.summet.com\/blog\/wp-json\/wp\/v2\/comments?post=1474"}],"version-history":[{"count":0,"href":"https:\/\/www.summet.com\/blog\/wp-json\/wp\/v2\/posts\/1474\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.summet.com\/blog\/wp-json\/wp\/v2\/media?parent=1474"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.summet.com\/blog\/wp-json\/wp\/v2\/categories?post=1474"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.summet.com\/blog\/wp-json\/wp\/v2\/tags?post=1474"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}