{"id":186,"date":"2024-04-06T19:39:10","date_gmt":"2024-04-06T17:39:10","guid":{"rendered":"http:\/\/theme-fusion.com\/avada\/classic\/?p=186"},"modified":"2024-11-08T19:00:58","modified_gmt":"2024-11-08T18:00:58","slug":"mikrovlnka","status":"publish","type":"post","link":"https:\/\/www.mwtc.tech\/index.php\/2024\/04\/06\/mikrovlnka\/","title":{"rendered":"Trochu infantiln\u00fd pokus s mikrovlnnou r\u00farou"},"content":{"rendered":"
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S dostupn\u00fdmi prostriedkami<\/h2><\/span>
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Nedalo mi to … V\u0161etky tie „overen\u00e9“ inform\u00e1cie o mikrovlnnej r\u00fare. Vy\u017earuje do prostredia? Upe\u010die ma, ke\u010f budem v jej bl\u00edzkosti? Ako je mo\u017en\u00e9, \u017ee ke\u010f do mikrovlnky vlo\u017e\u00edm mobil a zavol\u00e1m na\u0148, tak zazvon\u00ed. Ve\u010f to je „d\u00f4kaz“ toho, \u017ee to zariadenie je nebezpe\u010dn\u00e9…. M\u00f4\u017eeme si da\u0165 e\u0161te ve\u013ea ot\u00e1zok o tomto v princ\u00edpe kuchynskom pr\u00edstroji, na ktor\u00e9 dostaneme, bu\u010f zl\u00e9 alebo rozporupln\u00e9 odpovede.<\/p>\n

A tak som sa rozhodol str\u010di\u0165 do mikrovlnej r\u00fary nakonfigurovan\u00fa zapnut\u00fa Malinu, teda Raspberry Pi 4. WiFI na Raspberry bolo nakonfigurovane na 2,4GHz a m\u00f3d access point. Pokus, ako u\u017e samotn\u00fd \u010dl\u00e1nok nazna\u010duje bol trochu infantiln\u00fd, ale ak\u00fa tak\u00fa predstavu o tieniacej \u00fa\u010dinnosti mikrovlnky n\u00e1m vie poskytn\u00fa\u0165. R\u00fara pracuje na frekvencii 2,45 GHz a na tej mojej je nap\u00edsan\u00e9: V\u00fdkon mikrovlnenia 800 W. Ako meracie zariadenie som pou\u017eil mobil s nain\u0161talovanou aplik\u00e1ciou WiFi Analyzer<\/b> (tu sa skr\u00fdva nedokonalos\u0165 cel\u00e9ho pr\u00edbehu). Pri otvoren\u00fdch dvierkach som nameral -17 dBm<\/em> vzdialenosti asi 1 m od mikrovlnnej r\u00fary. Po uzatvoren\u00ed dvierok som pokus zopakoval a v\u00fdsledok bol -69 dBm<\/em>. Oby\u010dajn\u00fdm od\u010d\u00edtan\u00edm dostaneme tieniacu \u00fa\u010dinnos\u0165<\/p>\n<\/div>

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TF[db]=\u00a0-17-(-69)\u00a0=\u00a052\u00a0dB<\/span><\/p>\n

\u010c\u00edslo nie je ani ve\u013ek\u00e9 ani mal\u00e9. Na porovnanie, napr\u00edklad tieniaca kab\u00edna v na\u0161ej poprednej technickej vysokej \u0161kole FEI STU m\u00e1 viac ako 100 dB<\/em>. Ale pracujme z \u00fadajom 52 dB<\/em>. Na z\u00e1klade tohto \u010d\u00edsla m\u00f4\u017eeme vypo\u010d\u00edta\u0165 ak\u00fd v\u00fdkon \u017eiarenia bude 1 m od mikrovlnnej r\u00fary, ke\u010f je t\u00e1to zapnut\u00e1. Vieme, \u017ee<\/p>\n

TF=10logfrac{P1}{P2}<\/span><\/p>\n

Na mojej mikrovlnnej r\u00fare je nap\u00edsan\u00fd v\u00fdkon mikrovlnn\u00e9ho \u017eiarenia, ktor\u00fd je 800<\/em> W<\/em> a predpoklad\u00e1m, \u017ee \u017eiaden v\u00fdkon nebude spotrebovan\u00fd v komore mikrovlnnej r\u00fary, potom<\/p>\n

P_2 = frac{P_1}{10^{TF\/10}}=frac{800}{10^{5.2}}=5.047, mW<\/span><\/p>\n

Pozorn\u00fd \u010ditate\u013e ur\u010dite n\u00e1jde mno\u017estvo ch\u00fdb v metodike merania, ale ako predstava o tom ako vy\u017earuje mikrovlnn\u00e1 r\u00fara sa toto \u010d\u00edslo d\u00e1 pou\u017ei\u0165. Ak porovn\u00e1me vy\u017earovanie WIFI routera, alebo IoT, tak r\u00fara je na tom r\u00e1dovo lep\u0161ie. A ke\u010f vezmeme do \u00favahy \u010das ktor\u00fd je v prev\u00e1dzke tak to je vzh\u013eadom na celkov\u00fa expoz\u00edciu \u010dloveka MW \u017eiaren\u00edm, \u010fal\u0161\u00ed r\u00e1d.<\/p>\n

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\"quotes\"<\/div>\n
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Jestli se c\u00edt\u00ed\u0161 dob\u0159e, uklidni se, ono t\u011b to p\u0159ejde.<\/p>\n

– Edward A. Murphy<\/span><\/p>\n<\/div>\n<\/div>\n<\/div><\/div><\/div><\/div><\/div>\n","protected":false},"excerpt":{"rendered":"

Vy\u017earovanie mikrovlnnej r\u00fary a jej tieniaci faktor.<\/p>\n","protected":false},"author":1,"featured_media":5724,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[46],"tags":[],"class_list":["post-186","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-vysokofrekvencna-technika"],"_links":{"self":[{"href":"https:\/\/www.mwtc.tech\/index.php\/wp-json\/wp\/v2\/posts\/186","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.mwtc.tech\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.mwtc.tech\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.mwtc.tech\/index.php\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.mwtc.tech\/index.php\/wp-json\/wp\/v2\/comments?post=186"}],"version-history":[{"count":13,"href":"https:\/\/www.mwtc.tech\/index.php\/wp-json\/wp\/v2\/posts\/186\/revisions"}],"predecessor-version":[{"id":5738,"href":"https:\/\/www.mwtc.tech\/index.php\/wp-json\/wp\/v2\/posts\/186\/revisions\/5738"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.mwtc.tech\/index.php\/wp-json\/wp\/v2\/media\/5724"}],"wp:attachment":[{"href":"https:\/\/www.mwtc.tech\/index.php\/wp-json\/wp\/v2\/media?parent=186"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.mwtc.tech\/index.php\/wp-json\/wp\/v2\/categories?post=186"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.mwtc.tech\/index.php\/wp-json\/wp\/v2\/tags?post=186"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}