{"id":122,"date":"2014-03-14T02:58:20","date_gmt":"2014-03-14T02:58:20","guid":{"rendered":"http:\/\/elderslie-ars.org.uk\/?p=122"},"modified":"2014-04-05T02:49:48","modified_gmt":"2014-04-05T02:49:48","slug":"psk31-receiver-project-testing","status":"publish","type":"post","link":"http:\/\/elderslie-ars.org.uk\/?p=122","title":{"rendered":"PSK31 Receiver Project: Testing"},"content":{"rendered":"<p><a href=\"http:\/\/elderslie-ars.org.uk\/wp-content\/uploads\/2014\/04\/rf-amplifier-Q1.png\"><img loading=\"lazy\" class=\"size-medium wp-image-220 alignleft\" alt=\"rf amplifier Q1\" src=\"http:\/\/elderslie-ars.org.uk\/wp-content\/uploads\/2014\/04\/rf-amplifier-Q1-203x300.png\" width=\"203\" height=\"300\" srcset=\"http:\/\/elderslie-ars.org.uk\/wp-content\/uploads\/2014\/04\/rf-amplifier-Q1-203x300.png 203w, http:\/\/elderslie-ars.org.uk\/wp-content\/uploads\/2014\/04\/rf-amplifier-Q1.png 352w\" sizes=\"(max-width: 203px) 100vw, 203px\" \/><\/a>Testing of the PSK31 Receiver has shown that the audio output section is satisfactory. White noise is clearly heard on headphones inserted in the output jack socket. The level is easily controlled by preset resistor R8,\u00a0the gain control for IC2\u00a0(LM386) [<a href=\"http:\/\/www.rsgbshop.org\/acatalog\/PDF\/RSGB%20Centenary%20Receiver%2020m%20version%20circuit%20diagram.pdf\" target=\"_blank\">1<\/a>] . With an antenna connected to the board however the PSK31 tones were not heard. Further investigation showed that rf amplifer transistor Q1 was not the 2n3819 JFET specified. The relevant section of the board and schematic are shown below.<a href=\"http:\/\/elderslie-ars.org.uk\/wp-content\/uploads\/2014\/04\/schematic-rf-amplifier.png\"><img loading=\"lazy\" class=\" wp-image-223 alignright\" alt=\"schematic rf amplifier\" src=\"http:\/\/elderslie-ars.org.uk\/wp-content\/uploads\/2014\/04\/schematic-rf-amplifier-300x195.png\" width=\"314\" height=\"228\" \/><\/a><\/p>\n<p>The incorrect device seems to be marked as a BC256B. This is a pnp Bipolar transistor and not the JFET required.\u00a0It has been removed.\u00a0The board will be re-tested when\u00a0the 2n3819 is fitted. An update will follow.<\/p>\n<p>[1] <a title=\"Circuit Diagram\" href=\"http:\/\/www.rsgbshop.org\/acatalog\/PDF\/RSGB%20Centenary%20Receiver%2020m%20version%20circuit%20diagram.pdf\" target=\"_blank\">Complete Circuit Diagram<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"<p>Testing of the PSK31 Receiver has shown that the audio output section is satisfactory. White noise is clearly heard on headphones inserted in the output jack socket. The level is easily controlled by preset resistor R8,\u00a0the gain control for IC2\u00a0(LM386) [1] . With an antenna connected to the board however the PSK31 tones were not\u2026 <span class=\"read-more\"><a href=\"http:\/\/elderslie-ars.org.uk\/?p=122\">Read More &raquo;<\/a><\/span><\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":[],"categories":[9],"tags":[],"_links":{"self":[{"href":"http:\/\/elderslie-ars.org.uk\/index.php?rest_route=\/wp\/v2\/posts\/122"}],"collection":[{"href":"http:\/\/elderslie-ars.org.uk\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/elderslie-ars.org.uk\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/elderslie-ars.org.uk\/index.php?rest_route=\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"http:\/\/elderslie-ars.org.uk\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=122"}],"version-history":[{"count":9,"href":"http:\/\/elderslie-ars.org.uk\/index.php?rest_route=\/wp\/v2\/posts\/122\/revisions"}],"predecessor-version":[{"id":231,"href":"http:\/\/elderslie-ars.org.uk\/index.php?rest_route=\/wp\/v2\/posts\/122\/revisions\/231"}],"wp:attachment":[{"href":"http:\/\/elderslie-ars.org.uk\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=122"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/elderslie-ars.org.uk\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=122"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/elderslie-ars.org.uk\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=122"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}