{"id":662,"date":"2014-04-07T20:08:11","date_gmt":"2014-04-07T18:08:11","guid":{"rendered":"http:\/\/www.pa3hcm.nl\/?p=662"},"modified":"2021-01-18T17:20:38","modified_gmt":"2021-01-18T16:20:38","slug":"30m-qrp-transceiver-part-3","status":"publish","type":"post","link":"https:\/\/www.pa3hcm.nl\/?p=662","title":{"rendered":"30m QRP transceiver \u2013 Part 3"},"content":{"rendered":"\n
\"[image]\"<\/a>
Receiver part of the 30m QRP transceiver. From left to right: preselector, 1st mixer, IF filter, 2nd mixer, 8 MHz oscillator<\/figcaption><\/figure><\/div>\n\n\n\n

Now all LF parts and the VFO were finished, it was time to build the RF-part of the receiver.<\/p>\n\n\n\n\n\n\n\n

This receiver consists of multiple sections. The first section is the (fixed) preselector, which is a combination of a bandpass filter for 10 MHz and a band reject filter for 6 MHz. The 6 MHz band must be filtered out, since this band contains lots of strong AM broadcast stations and is also the mirror frequency for this receiver: the input signal is mixed with the 2.10-2.15 MHz VFO frequency. The 10 MHz band is mixed down to the 8 MHz IF (10.1 – 2.1 = 8 MHz). simultaneously 6 MHz is mixed up to 8 MHz (5.9 + 2.1 = 8 MHz), disturbing our reception. So getting rid of the 6 MHz is very important.<\/p>\n\n\n\n

I soldered each mixer (SA612) onto a very small part of breadboard (6×4 pads), with the solder side upward. Then I put the breadboard on my desk and placed the DIL-8 packaged chip in the center. Along each row of pins a row of pads remains unused for the moment. The pins of the chip line up with the (normally) component side of the board. Then I soldered the pins to the pads, with the chip package on a small distance of the board. Finally I soldered the directly connected components on the unused pads (through-hole mounting is not necessary) and connected them to the corresponding pin.<\/p>\n\n\n\n

Just behind the first mixer is the IF filter. This is made of 3 crystals of 8 MHz. The output of the filter is inserted in a second mixer with an 8 MHz fixed oscillator. The output is the LF signal, ready to be inserted into the LF filter and amplifier.<\/p>\n\n\n\n

I managed to put the preselector, IF filter, both mixers and the 8 MHz oscillator at a small piece of copper clad, which measures only 7×3 cm. See the pictures how I did this!<\/p>\n\n\n\n

\"[image]\"<\/a>
Another view of the receiver part of the 30m QRP transceiver.<\/figcaption><\/figure><\/div>\n","protected":false},"excerpt":{"rendered":"

Now all LF parts and the VFO were finished, it was time to build the RF-part of the receiver.<\/p>\n","protected":false},"author":1,"featured_media":664,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[14],"tags":[55,87,28,79,30,29],"class_list":["post-662","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-transmitters_and_receivers","tag-30m","tag-40-30","tag-cw","tag-manhattan-style","tag-qrp","tag-transceiver"],"blocksy_meta":{"styles_descriptor":{"styles":{"desktop":"","tablet":"","mobile":""},"google_fonts":[],"version":6}},"_links":{"self":[{"href":"https:\/\/www.pa3hcm.nl\/index.php?rest_route=\/wp\/v2\/posts\/662","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.pa3hcm.nl\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.pa3hcm.nl\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.pa3hcm.nl\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.pa3hcm.nl\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=662"}],"version-history":[{"count":8,"href":"https:\/\/www.pa3hcm.nl\/index.php?rest_route=\/wp\/v2\/posts\/662\/revisions"}],"predecessor-version":[{"id":1901,"href":"https:\/\/www.pa3hcm.nl\/index.php?rest_route=\/wp\/v2\/posts\/662\/revisions\/1901"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.pa3hcm.nl\/index.php?rest_route=\/wp\/v2\/media\/664"}],"wp:attachment":[{"href":"https:\/\/www.pa3hcm.nl\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=662"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.pa3hcm.nl\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=662"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.pa3hcm.nl\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=662"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}