From FB group Building Transistor Radios, Jul 30<\/p>\n
Hey, if you live in Central Florida, you really do need an optocoupler!<\/p>\n
I got a Tennelec Memoryscan scanner on sale for a really cheap price back in the ’70s (the company quickly went out of business). I connected it to a VHF\/UHF discone antenna on my roof. This had 3 elements only a few feet in diameter.<\/p>\n
So a thunderstorm passed through and afterwards the VHF channels stopped working – UHF were ok.<\/p>\n
Fortunately it came with a schematic. I immediately saw why. The VHF RF amp was directly connected to the antenna. No coil to give a DC path to ground. So I replaced the 2N3904 RF amp, and it started working again. So it’s a Big Mistake to connect a transistor, and especially a FET(!) to the antenna directly. Many good designs totally ignore this absolute no-no! And it happened to me with a tiny discone antenna. Imagine what happens with a hundred foot long wire!!<\/p>\n","protected":false},"excerpt":{"rendered":"
From FB group Building Transistor Radios, Jul 30 Hey, if you live in Central Florida, you really do need an optocoupler! I got a Tennelec Memoryscan scanner on sale for a really cheap price back in the ’70s (the company quickly went out of business). I connected it to a VHF\/UHF discone antenna on my <\/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":[7,262],"tags":[],"class_list":["post-13034","post","type-post","status-publish","format-standard","hentry","category-radio-frequency","category-receiver"],"_links":{"self":[{"href":"https:\/\/rustybolt.info\/wordpress\/index.php?rest_route=\/wp\/v2\/posts\/13034","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=13034"}],"version-history":[{"count":1,"href":"https:\/\/rustybolt.info\/wordpress\/index.php?rest_route=\/wp\/v2\/posts\/13034\/revisions"}],"predecessor-version":[{"id":13035,"href":"https:\/\/rustybolt.info\/wordpress\/index.php?rest_route=\/wp\/v2\/posts\/13034\/revisions\/13035"}],"wp:attachment":[{"href":"https:\/\/rustybolt.info\/wordpress\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=13034"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/rustybolt.info\/wordpress\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=13034"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/rustybolt.info\/wordpress\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=13034"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}