{"id":5820,"date":"2024-04-06T19:39:10","date_gmt":"2024-04-06T17:39:10","guid":{"rendered":"https:\/\/www.mwtc.tech\/index.php\/2024\/04\/06\/a-somewhat-infantile-experiment-with-a-microwave-oven\/"},"modified":"2024-11-13T23:42:33","modified_gmt":"2024-11-13T22:42:33","slug":"a-somewhat-infantile-experiment-with-a-microwave-oven","status":"publish","type":"post","link":"https:\/\/www.mwtc.tech\/index.php\/2024\/04\/06\/a-somewhat-infantile-experiment-with-a-microwave-oven\/?lang=en","title":{"rendered":"A somewhat infantile experiment with a microwave oven"},"content":{"rendered":"
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With available resources<\/h2><\/span>
<\/div><\/div><\/div>

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. 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>

<\/span><\/div>

TF[db]= -17-(-69) = 52 dB<\/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

An attentive reader will certainly find many errors in the measurement methodology, but this number can be used as an idea of how a microwave oven radiates. If we compare the radiation of a WIFI router or IoT, the oven is an order of magnitude better. And when we take into account the time it is in operation, it is another order of magnitude with respect to the total exposure of a person to MW radiation. <\/p>\n

\n
\"quotes\"<\/div>\n
\n

If you feel good, take it easy, it will pass.<\/p>\n

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

Microwave radiation and its shielding factor.<\/p>\n","protected":false},"author":1,"featured_media":5823,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[71],"tags":[],"class_list":["post-5820","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-rf-techniques"],"_links":{"self":[{"href":"https:\/\/www.mwtc.tech\/index.php\/wp-json\/wp\/v2\/posts\/5820","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=5820"}],"version-history":[{"count":3,"href":"https:\/\/www.mwtc.tech\/index.php\/wp-json\/wp\/v2\/posts\/5820\/revisions"}],"predecessor-version":[{"id":5826,"href":"https:\/\/www.mwtc.tech\/index.php\/wp-json\/wp\/v2\/posts\/5820\/revisions\/5826"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.mwtc.tech\/index.php\/wp-json\/wp\/v2\/media\/5823"}],"wp:attachment":[{"href":"https:\/\/www.mwtc.tech\/index.php\/wp-json\/wp\/v2\/media?parent=5820"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.mwtc.tech\/index.php\/wp-json\/wp\/v2\/categories?post=5820"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.mwtc.tech\/index.php\/wp-json\/wp\/v2\/tags?post=5820"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}