{"id":1531,"date":"2013-09-29T19:16:00","date_gmt":"2013-09-29T09:16:00","guid":{"rendered":"https:\/\/www.homebrewradio.us\/blog\/2013\/09\/29\/bitx-build-update-11-peakin-and-tweakin\/"},"modified":"2013-09-29T19:16:00","modified_gmt":"2013-09-29T09:16:00","slug":"bitx-build-update-11-peakin-and-tweakin","status":"publish","type":"post","link":"https:\/\/www.homebrewradio.us\/blog\/2013\/09\/29\/bitx-build-update-11-peakin-and-tweakin\/","title":{"rendered":"BITX Build Update #11 &#8212; Peakin&#8217; and Tweakin&#8217;"},"content":{"rendered":"<p><strong>Oh how I love the sound of a newly built receiver! I&#8217;m sitting here listening to G0MJS on 17 meters. Lots of other stations from across the pond coming in very nicely. <\/strong><br \/> <strong><\/strong><br \/> <strong>Earlier in the week I had some sensitivity problems. I could hear the noise floor, but just barely. And the receiver just seemed to have trouble inhaling. So I started poking around. It seemed that each poke improved things a bit. I had used Farhan&#8217;s original schematic (mostly). Later versions put an additional transistor in the IF amp. So I went ahead and added that mod. That helped a bit. Then I noticed that BFO energy was getting into the AF amp. So I put a .1uF cap to ground at the input to the AF preamp. That took care of the RF and did no damage to the AF. <\/strong><br \/> <strong><\/strong><br \/> <strong>But the rig still seemed a bit hard of hearing. This morning Farhan advised me to take a look at the mixers. I used some junk-box diodes that I didn&#8217;t know too much about&#8230; I measured the forward resistance and found it to be quite a bit higher than the usual 1N914s. So I switched all 6 mixer diodes. That helped noticeably. <\/strong><br \/> <strong><\/strong><br \/> <strong>I also checked the input bandpass filter. It seems OK. In the process I learned to use the EMRFD filter programs (thanks Wes) and the ELSIE filter program (also very nice). <\/strong><br \/> <strong><\/strong><br \/> <strong>Anyway, the rig sounds great now. On to the transmitter. <\/strong><br \/> <strong><\/strong><br \/> <strong>Farhan advises building the power amplifier on a separate copper clad board. But I have room for it on my main board. Should I live dangerously?<\/strong> <\/p>\n<p> Our book: &#8220;SolderSmoke &#8212; Global Adventures in Wireless Electronics&#8221; <a href=\"http:\/\/soldersmoke.com\/book.htm\">http:\/\/soldersmoke.com\/book.htm<\/a> Our coffee mugs, T-Shirts, bumper stickers: <a href=\"http:\/\/www.cafepress.com\/SolderSmoke\">http:\/\/www.cafepress.com\/SolderSmoke<\/a> Our Book Store: <a href=\"http:\/\/astore.amazon.com\/contracross-20\">http:\/\/astore.amazon.com\/contracross-20<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"<p>Oh how I love the sound of a newly built receiver! I&#8217;m sitting here listening to G0MJS on 17 meters. Lots of other stations from across the pond coming in very nicely. Earlier in the week I had some sensitivity problems. I could hear the noise floor, but just barely. And the receiver just seemed &hellip; <a href=\"https:\/\/www.homebrewradio.us\/blog\/2013\/09\/29\/bitx-build-update-11-peakin-and-tweakin\/\" class=\"more-link\">Continue reading<span class=\"screen-reader-text\"> &#8220;BITX Build Update #11 &#8212; Peakin&#8217; and Tweakin&#8217;&#8221;<\/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":[28,66,60],"tags":[],"class_list":["post-1531","post","type-post","status-publish","format-standard","hentry","category-bitx20","category-farhan","category-hayward-wes"],"_links":{"self":[{"href":"https:\/\/www.homebrewradio.us\/blog\/wp-json\/wp\/v2\/posts\/1531","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.homebrewradio.us\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.homebrewradio.us\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.homebrewradio.us\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.homebrewradio.us\/blog\/wp-json\/wp\/v2\/comments?post=1531"}],"version-history":[{"count":0,"href":"https:\/\/www.homebrewradio.us\/blog\/wp-json\/wp\/v2\/posts\/1531\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.homebrewradio.us\/blog\/wp-json\/wp\/v2\/media?parent=1531"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.homebrewradio.us\/blog\/wp-json\/wp\/v2\/categories?post=1531"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.homebrewradio.us\/blog\/wp-json\/wp\/v2\/tags?post=1531"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}