I noticed that my photo didn\u2019t get added to the photos tab, So I\u2019m trying again to add it.<\/p>\n\n\n\n
I got a fresh start this Sat. morning. I used another little air band\n receiver to listen for the LO from this one. I turned the tuning pot to\n minimum which should be 118.00 MHz. I then set the other receiver to \n118 + 10.7 or 128.7 MHz. I used a nylon tuning wand to tune the LO \ncoil\u2019s brass slug until I heard the LO fully quiet at 128.7. The speaker\n has hiss at this setting.<\/p>\n\n\n\n
I then set the little receiver for 130, 132, 134, 136, and 138.0 MHz \n(highest it would go), and each time I could hear the LO in the little \nreceiver as I advanced the tune pot. So the LO is oscillating all the \nway up to 138. But with the brass slug out most of the way, as soon as I\n tuned to 130, the hiss from the speaker went down to nothing and stayed\n quiet for all the other frequencies, too. This is puzzling.<\/p>\n\n\n\n
I could hear transmissions on some frequencies in the little \nreceiver. There is activity in the band. This little receiver uses a \npair of ear buds for listening, and the antenna is the wires of the ear \nbuds. So the transmissions have plenty of strength to be heard on a \nshort lengths of wire, which is what I\u2019m using for this receiver. But I \nhave heard nothing but hiss on this receiver or no hiss, wherever I have\n tuned it.<\/p>\n\n\n\n
I\u2019m even more puzzled.<\/p>\n\n\n\n
Update late afternoon \u2013 I forgot I had my Gy560 frequency counter in \nthe drawer. I pulled it out and I touched its antenna to the slug and it\n gave me a reading. With the tune pot at minimum I set the slug for 118 +\n 10.7 or 128.7 MHz. As I tuned the pot, I could see the LO frequency go \nup and up. It should go as high as 136 + 10.7 or 146.7 MHz. But it kept \ngoing higher, all the way up to 158.7 MHz. That\u2019s okay, but I would \nrather have the pot have a smaller range with greater resolution. So \nI\u2019ll have to change the resistors to get the right range. But first I \nhave to get it to receive a signal.<\/p>\n\n\n\n
One thing that bothered me was the PCB coils dipping as high as 200 \nMHz. So I removed one leg of the C5 DC blocking capacitor, and I \nsoldered a tiny switch to the leg so I can choose to have the antenna \nsignal go through the coils on the PCB or bypass the coils and go \ndirectly to Q1. I tried a short length of antenna into the Q1 and it \nstill does not receive any signals across the band. But I can hear the \nstrong signal from my dipmeter at two places on the band, one below and \none above the LO frequency, so it seems to be receiving very strong \nsignals.<\/p>\n\n\n\n Posted to FB group Building Transistor Radios 2018-10-06 First part is here. I noticed that my photo didn\u2019t get added to the photos tab, So I\u2019m trying again to add it. I got a fresh start this Sat. morning. I used another little air band receiver to listen for the LO from this one. I <\/p>\n (Read More…)<\/a><\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[],"class_list":["post-13113","post","type-post","status-publish","format-standard","hentry","category-uncategorized"],"_links":{"self":[{"href":"https:\/\/rustybolt.info\/wordpress\/index.php?rest_route=\/wp\/v2\/posts\/13113","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/rustybolt.info\/wordpress\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/rustybolt.info\/wordpress\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/rustybolt.info\/wordpress\/index.php?rest_route=\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/rustybolt.info\/wordpress\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=13113"}],"version-history":[{"count":2,"href":"https:\/\/rustybolt.info\/wordpress\/index.php?rest_route=\/wp\/v2\/posts\/13113\/revisions"}],"predecessor-version":[{"id":13115,"href":"https:\/\/rustybolt.info\/wordpress\/index.php?rest_route=\/wp\/v2\/posts\/13113\/revisions\/13115"}],"wp:attachment":[{"href":"https:\/\/rustybolt.info\/wordpress\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=13113"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/rustybolt.info\/wordpress\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=13113"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/rustybolt.info\/wordpress\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=13113"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}![\"\"\/](\"https:\/\/rustybolt.info\/wordpress\/wp-content\/uploads\/2018\/10\/IMG_20181005_122658.jpg\")
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