{"id":33117,"date":"2019-10-31T21:50:51","date_gmt":"2019-10-31T18:50:51","guid":{"rendered":"https:\/\/prohoster.info\/blog\/chto-slyshno-v-radioefire-prinimaem-i-dekodiruem-naibolee-interesnye-signaly-chast-2-ukv\/"},"modified":"2019-10-31T21:50:51","modified_gmt":"2019-10-31T18:50:51","slug":"chto-slyshno-v-radioefire-prinimaem-i-dekodiruem-naibolee-interesnye-signaly-chast-2-ukv","status":"publish","type":"post","link":"https:\/\/prohoster.info\/hr\/blog\/administrirovanie\/chto-slyshno-v-radioefire-prinimaem-i-dekodiruem-naibolee-interesnye-signaly-chast-2-ukv","title":{"rendered":"\u0160to se \u010duje na radiju? Primamo i de\u0161ifriramo najzanimljivije signale. Dio 2, FM","gt_translate_keys":[{"key":"rendered","format":"text"}]},"content":{"rendered":"<p>Pozdrav, Habr.<\/p>\n<p>U <noindex><a rel=\"nofollow\" href=\"https:\/\/habr.com\/ru\/post\/450534\/\">prvom delu<\/a><\/noindex> opisani su neki signali koji se mogu primiti na dugim i kratkim valovima. Podru\u010dje FM tako\u0111er je zanimljivo, gdje se tako\u0111er mo\u017ee prona\u0107i ne\u0161to zanimljivo.<\/p>\n<p><img decoding=\"async\" alt=\"\u0160to se \u010duje na radiju? Primamo i de\u0161ifriramo najzanimljivije signale. Dio 2, FM\" src=\"\/wp-content\/uploads\/2019\/05\/07002c58962c751234675239f7428c33.jpg\" style=\"display:block;margin: 0 auto;\" \/><br \/>\nKao i u prvom dijelu, razmotrit \u0107emo signale koje mo\u017eemo sami de\u0161ifrirati uz pomo\u0107 ra\u010dunala. Tko je znati\u017eeljan kako to funkcionira, nastavak je ispod.<br \/>\n<noindex><a rel=\"nofollow\" name=\"habracut\"><\/a><\/noindex><br \/>\nU prvom dijelu koristili smo nizozemski <noindex><a rel=\"nofollow\" href=\"http:\/\/websdr.ewi.utwente.nl:8901\/\">online prijemnik<\/a><\/noindex> za prijem dugih i kratkih valova. Na\u017ealost, za FM ne postoje sli\u010dne usluge \u2014 opseg frekvencija je prevelik. Stoga \u0107e svi koji \u017eele ponoviti dolje opisane eksperimente morati nabaviti vlastiti prijemnik, od najjeftinijih mo\u017ee se istaknuti <noindex><a rel=\"nofollow\" href=\"https:\/\/www.rtl-sdr.com\/wp-content\/uploads\/2018\/02\/RTL-SDR-Blog-V3-Datasheet.pdf\">RTL SDR V3<\/a><\/noindex>, koji se mo\u017ee nabaviti za 30$. Ovaj prijemnik pokriva opseg do 1.7 GHz, svi dolje opisani signali primljeni su upravo na njega. <\/p>\n<p>Dakle, krenimo. Kao i u prvom dijelu, signale \u0107emo razmatrati prema rastu\u0107oj frekvenciji.<\/p>\n<h2>FM radio<\/h2>\n<p>\nSam FM radio vjerojatno ne\u0107e iznenaditi mnoge, a nas \u0107e zanimati RDS unutar njega. RDS (Radio Data System) omogu\u0107uje prijenos digitalnih podataka 'unutar' FM signala. Spektar FM signala nakon demodulacije izgleda ovako:<\/p>\n<p><img decoding=\"async\" alt=\"\u0160to se \u010duje na radiju? Primamo i de\u0161ifriramo najzanimljivije signale. Dio 2, FM\" src=\"\/wp-content\/uploads\/2019\/05\/47dcf140dffda67ddc71c0a0211c3caf.jpg\" style=\"display:block;margin: 0 auto;\" \/><br \/>\n<br \/>\nNa frekvenciji 19 kHz nalazi se pilot ton, dok se na njegovoj trostrukoj frekvenciji 57 kHz prenosi RDS signal. Na oscilogramu, kada su oba signala prikazana zajedno, to izgleda otprilike ovako:<\/p>\n<p><img decoding=\"async\" alt=\"\u0160to se \u010duje na radiju? Primamo i de\u0161ifriramo najzanimljivije signale. Dio 2, FM\" src=\"\/wp-content\/uploads\/2019\/05\/beae4480f5b7e1ab3d223d379b26482f.jpg\" style=\"display:block;margin: 0 auto;\" \/><br \/>\n<br \/>\nPomo\u0107u fazne modulacije ovdje je kodiran nizkofrekventni signal s frekvencijom 1187.5 Hz (usput, frekvencija 1187.5 Hz nije odabrana slu\u010dajno \u2014 to je frekvencija 19 kHz pilot tona podijeljena s 16). Nakon bit po bit dekodiranja, de\u0161ifriraju se paketi podataka, kojih je dosta vrsta \u2014 osim teksta, mogu se, primjerice, prenositi alternativne frekvencije emitiranja radiostanice, i kada se u\u0111e u drugo podru\u010dje prijemnik se mo\u017ee automatski prebaciti na novu frekvenciju. <\/p>\n<p>Primiti RDS podatke lokalnih postaja mo\u017ee se putem programa <noindex><a rel=\"nofollow\" href=\"http:\/\/rdsspy.com\/downloads\/\">RDS Spy<\/a><\/noindex>. Mo\u017ee se povezati preko HDSDR-a, odabirom FM modulacije, \u0161irinom signala 120 kHz i bit rateom 192 kHz, kao \u0161to je prikazano na slici.<\/p>\n<p><img decoding=\"async\" alt=\"\u0160to se \u010duje na radiju? Primamo i de\u0161ifriramo najzanimljivije signale. Dio 2, FM\" src=\"\/wp-content\/uploads\/2019\/05\/22b0df17bcb4e8abbea55c66cc5bf2b3.jpg\" style=\"display:block;margin: 0 auto;\" \/><br \/>\n<br \/>\nZatim je dovoljno preusmjeriti signal putem Virtual Audio Cable-a s HDSDR-a na RDS Spy (u postavkama VAC tako\u0111er treba odabrati bitrate 192 kHz). Ako je sve pravilno u\u010dinjeno, vidjet \u0107emo sve informacije o RDS-u, mnogo vi\u0161e nego \u0161to \u0107e pokazati obi\u010dni ku\u0107ni radio prijemnik:<\/p>\n<p><img decoding=\"async\" alt=\"\u0160to se \u010duje na radiju? Primamo i de\u0161ifriramo najzanimljivije signale. Dio 2, FM\" src=\"\/wp-content\/uploads\/2019\/05\/742b3706c8130cffce9125802a0253e9.jpg\" style=\"display:block;margin: 0 auto;\" \/><br \/>\n<br \/>\nOsim FM, mo\u017ee se de\u0161ifrirati i DAB+, za \u0161to je bio <noindex><a rel=\"nofollow\" href=\"https:\/\/habr.com\/ru\/post\/448244\/\">odvojeni \u010dlanak<\/a><\/noindex>. U Rusiji trenutno ne funkcionira, ali u drugim zemljama mo\u017ee biti relevantno.<\/p>\n<h2>Aviodijalog<\/h2>\n<p>\nTako je historijski postavljeno da se u avijaciji koristi amplitude modulation (AM) i frekvencijski raspon 118-137 MHz. Razgovori pilota i kontrolora leta nisu nikako \u0161ifrirani, te ih mo\u017ee primiti svatko tko \u017eeli. Prije 20 godina, za to su se koristili obi\u010dni jeftini kineski radio prijemnici \u2014 dovoljno je bilo pomaknuti zavojnice heterodina i frekvencija se pomicala, a ako je bilo sre\u0107e, u smjeru vi\u0161ih frekvencija. Zainteresirani za \"digitalnu arheologiju\" mogu pro\u010ditati raspravu <noindex><a rel=\"nofollow\" href=\"http:\/\/www.radioscanner.ru\/forum\/topic13565.html\">na forumu radioscanner<\/a><\/noindex> iz 2004. godine. Kasnije su kineski proizvo\u0111a\u010di iza\u0161li u susret korisnicima i jednostavno dodali raspon Air u prijemnike (u komentarima prve dijela preporu\u010divali su Tecsun PL-660 ili PL-680). Naravno, kori\u0161tenje specijaliziranih ure\u0111aja (primjerice, prijemnika AOR, Icom) je mnogo po\u017eeljnije \u2014 oni imaju \u0161umovni filtar (zvuk se isklju\u010duje kada nema signala i nema stalnog \u0161uma) i ve\u0107u brzinu pretra\u017eivanja frekvencija.<\/p>\n<p>Svaka ve\u0107a zra\u010dna luka koristi prili\u010dno mnogo frekvencija, evo primjera, frekvencije zra\u010dne luke Pulkovo, uzete s web stranice radioscanner:<\/p>\n<p><img decoding=\"async\" alt=\"\u0160to se \u010duje na radiju? Primamo i de\u0161ifriramo najzanimljivije signale. Dio 2, FM\" src=\"\/wp-content\/uploads\/2019\/05\/c1b79780a12362f182b215d7dc5117e8.jpg\" style=\"display:block;margin: 0 auto;\" \/><br \/>\n<br \/>\nUsput, prijenose razgovora iz raznih ruskih gradova (Moskva, S-Pb, \u010celjabinsk i neki drugi) mo\u017eete slu\u0161ati online na <noindex><a rel=\"nofollow\" href=\"http:\/\/live.radioscanner.net\/\">http:\/\/live.radioscanner.net<\/a><\/noindex>. <\/p>\n<p>Za nas je u aviodijalu zanimljiv digitalni protokol <noindex><a rel=\"nofollow\" href=\"https:\/\/ru.wikipedia.org\/wiki\/ACARS\">ACARS<\/a><\/noindex> (Aircraft Communications Addressing and Reporting System). Njegovi signali se prenose na frekvencijama 131.525 i 131.725 MHz (europski standard, frekvencije razli\u010ditih regija <noindex><a rel=\"nofollow\" href=\"https:\/\/www.acarsd.org\/ACARS_frequencies.html\">mogu se razlikovati<\/a><\/noindex>). To su digitalne poruke s bitrate-om 2400 ili 1200 bps, putem takvog sustava piloti mogu razmjenjivati poruke s kontrolorom leta. Za dekodiranje u MultiPSK treba se postaviti na signal u AM re\u017eimu (potreban je SDR prijemnik, budu\u0107i da je \u0161irina pojasa signala ve\u0107a od 5 kHz) i preusmjeriti zvuk putem Virtual Audio Card. <\/p>\n<p>Rezultat je prikazan na snimci ekrana.<\/p>\n<p><img decoding=\"async\" alt=\"\u0160to se \u010duje na radiju? Primamo i de\u0161ifriramo najzanimljivije signale. Dio 2, FM\" src=\"\/wp-content\/uploads\/2019\/05\/6a4bf480d2f932cddbb9c4935c488f73.jpg\" style=\"display:block;margin: 0 auto;\" \/><br \/>\n<br \/>\nFormat signala ACARS je prili\u010dno jednostavan, a mo\u017ee se pregledati u programu SA Free. Dovoljno je otvoriti fragment zapisa, i vidjet \u0107emo da \"unutar\" AM zapisa zapravo postoji frekvencijska modulacija.<\/p>\n<p><img decoding=\"async\" alt=\"\u0160to se \u010duje na radiju? Primamo i de\u0161ifriramo najzanimljivije signale. Dio 2, FM\" src=\"\/wp-content\/uploads\/2019\/05\/6de57323223f2e4eac8328ac77563c0f.jpg\" style=\"display:block;margin: 0 auto;\" \/><br \/>\n<br \/>\nNakon toga, primjenom frekvencijskog detektora na zapis, lako dobivamo bitstream. U stvarnosti, te\u0161ko da \u0107e se to raditi, jer su gotovi programi za dekodiranje ACARS-a ve\u0107 davno napisani.<\/p>\n<h2>Meteosateliti NOAA<\/h2>\n<p>\nSlu\u0161aju\u0107i razgovore avioprijevoznika, mo\u017eemo se popeti \u010dak i vi\u0161e \u2014 u svemir. U kojem su nam zanimljivi meteosateliti <noindex><a rel=\"nofollow\" href=\"https:\/\/en.wikipedia.org\/wiki\/NOAA-15\">NOAA 15<\/a><\/noindex>, <noindex><a rel=\"nofollow\" href=\"https:\/\/en.wikipedia.org\/wiki\/NOAA-18\">NOAA 18<\/a><\/noindex> i <noindex><a rel=\"nofollow\" href=\"https:\/\/en.wikipedia.org\/wiki\/NOAA-19\">NOAA 19<\/a><\/noindex>, koji prenose slike povr\u0161ine Zemlje na frekvencijama 137.620, 137.9125 i 137.100MHz. Signal se mo\u017ee dekodirati pomo\u0107u programa <noindex><a rel=\"nofollow\" href=\"https:\/\/wxtoimgrestored.xyz\/downloads\/\">WXtoImg<\/a><\/noindex>.<\/p>\n<p>Primljena slika mo\u017ee izgledati otprilike ovako (slika s web stranice radioscanner):<\/p>\n<p><img decoding=\"async\" alt=\"\u0160to se \u010duje na radiju? Primamo i de\u0161ifriramo najzanimljivije signale. Dio 2, FM\" src=\"\/wp-content\/uploads\/2019\/05\/5987ac91e7333d37a04be18e34117e36.jpg\" style=\"display:block;margin: 0 auto;\" \/><br \/>\n<br \/>\nNa\u017ealost (zakoni fizike se ne mogu prevariti, a Zemlja je ipak okrugla iako ne vjeruju svi u to), signal satelita se mo\u017ee primiti samo kada leti iznad nas, i ne uvijek su ti letovi u prikladno vrijeme i pod pravim kutom iznad horizonta. Nekada je za saznanje vremena i datuma najbli\u017eeg leta trebalo instalirati program <noindex><a rel=\"nofollow\" href=\"http:\/\/www.stoff.pl\/\">Orbitron<\/a><\/noindex> (program-legend koji postoji od 2001. godine), sada je to lak\u0161e u\u010diniti online putem linkova <noindex><a rel=\"nofollow\" href=\"https:\/\/www.n2yo.com\/passes\/?s=25338\">https:\/\/www.n2yo.com\/passes\/?s=25338<\/a><\/noindex>, <noindex><a rel=\"nofollow\" href=\"https:\/\/www.n2yo.com\/passes\/?s=28654\">https:\/\/www.n2yo.com\/passes\/?s=28654<\/a><\/noindex> i <noindex><a rel=\"nofollow\" href=\"https:\/\/www.n2yo.com\/passes\/?s=33591\">https:\/\/www.n2yo.com\/passes\/?s=33591<\/a><\/noindex> odgovaraju\u0107e. <\/p>\n<p>Signal satelita je prili\u010dno jak i \u010duje se gotovo na svaku antensko i svaku prijemniku. No, kako bi se primila slika dobre kvalitete, ipak je po\u017eeljna posebna antena i dobar pregled horizonta. Oni koji \u017eele mogu pogledati <noindex><a rel=\"nofollow\" href=\"https:\/\/youtu.be\/0efTTWMl3v0?t=19\">anglophoneski tutorijal na youtube<\/a><\/noindex> ili pro\u010ditati <noindex><a rel=\"nofollow\" href=\"https:\/\/www.rtl-sdr.com\/rtl-sdr-tutorial-receiving-noaa-weather-satellite-images\/\">detaljan opis<\/a><\/noindex>. Osobno, nisam imao strpljenja dovr\u0161iti to, ali mo\u017eda \u0107e drugim biti sretniji.<\/p>\n<h2>Paging poruke FLEX\/POCSAG<\/h2>\n<p>\nRadi li jo\u0161 paging komunikacija za korporativne klijente u Rusiji, ne znam, dok u Europi ona sasvim dobro funkcionira, koriste je vatrogasci, policija i razne slu\u017ebe. <\/p>\n<p>Signale FLEX i POCSAG mogu\u0107e je primiti pomo\u0107u HDSDR i Virtual Audio Cable, dok se za dekodiranje koristi program <noindex><a rel=\"nofollow\" href=\"https:\/\/www.discriminator.nl\/pdw\/\">PDW<\/a><\/noindex>. Napisan je 2004. godine, a su\u010delje mu odgovara, ali iznena\u0111uju\u0107e, jo\u0161 uvijek funkcioni\u0161e.<\/p>\n<p><img decoding=\"async\" alt=\"\u0160to se \u010duje na radiju? Primamo i de\u0161ifriramo najzanimljivije signale. Dio 2, FM\" src=\"\/wp-content\/uploads\/2019\/05\/42bee0f2a5b253d94dbc1489c9f972e1.jpg\" style=\"display:block;margin: 0 auto;\" \/><br \/>\n<br \/>\nTako\u0111er postoji dekoder multimon-ng, koji radi pod Linuxom, a njegovi izvorni kodovi su dostupni <noindex><a rel=\"nofollow\" href=\"https:\/\/github.com\/EliasOenal\/multimon-ng\">na githubu<\/a><\/noindex>. O protokolu prijenosa POCSAG tako\u0111er postoji poseban \u010dlanak, oni zainteresirani mogu se upoznati s njim <noindex><a rel=\"nofollow\" href=\"https:\/\/habr.com\/ru\/post\/438602\/\">detaljnije<\/a><\/noindex>.<\/p>\n<h2>Daljinski prekida\u010di<\/h2>\n<p>\nNa 433MHz nalaze se razna ure\u0111aja \u2014 be\u017ei\u010dni prekida\u010di i uti\u010dnice, zvona, senzori pritiska guma automobila i sli\u010dno. <\/p>\n<p><img decoding=\"async\" alt=\"\u0160to se \u010duje na radiju? Primamo i de\u0161ifriramo najzanimljivije signale. Dio 2, FM\" src=\"\/wp-content\/uploads\/2019\/05\/eab3a22484e00ff9f42a51cadeba1265.jpg\" style=\"display:block;margin: 0 auto;\" \/><br \/>\n<br \/>\nTo su \u010desto jeftini kineski ure\u0111aji s najjednostavnijom modifikacijom. Nema nikakvog \u0161ifriranja, a koristi se jednostavni binarni kod (OOK \u2014 on-off keying). Dekodiranje takvih signala razmatrano je u <noindex><a rel=\"nofollow\" href=\"https:\/\/habr.com\/ru\/post\/414285\/\">odvojenom \u010dlanku<\/a><\/noindex>. Mo\u017eemo koristiti gotovi dekoder rtl_433, koji se mo\u017ee preuzeti <noindex><a rel=\"nofollow\" href=\"https:\/\/cognito.me.uk\/computers\/rtl_433-windows-binary-32-bit\/\">odavde<\/a><\/noindex>. <\/p>\n<p><img decoding=\"async\" alt=\"\u0160to se \u010duje na radiju? Primamo i de\u0161ifriramo najzanimljivije signale. Dio 2, FM\" src=\"\/wp-content\/uploads\/2019\/05\/020c4302a1ffe5d609eef949e19f304d.jpg\" style=\"display:block;margin: 0 auto;\" \/><br \/>\n<br \/>\nPokretanjem programa, mo\u017eete vidjeti razli\u010dite ure\u0111aje, a (ako se u blizini nalaze parkirani automobili) saznati, na primjer, pritisak u gumama susjedovog automobila. Prakti\u010dnog smisla u tome nema puno, ali sa \u010disto matemati\u010dke to\u010dke gledi\u0161ta, prili\u010dno je zanimljivo \u2014 protokoli tih signala su jednostavni za dekodiranje.<\/p>\n<p>Usput, kupci takvih be\u017ei\u010dnih prekida\u010da trebali bi imati na umu da nisu za\u0161ti\u0107eni, i teoretski va\u0161 haker-susjed s HackRF ili sli\u010dnim ure\u0111ajem mogao bi vam isklju\u010diti svjetlo u kupaonici u najneprikladnijem trenutku ili u\u010diniti ne\u0161to sli\u010dno. Osobno se ne optere\u0107ujem time, ali ako je pitanje sigurnosti aktualno, mo\u017eete koristiti ozbiljnije i skuplje ure\u0111aje s pravim klju\u010devima i autentifikacijom (Z-Wave, Philips Hue itd.).<\/p>\n<h2>TETRA<\/h2>\n<p>\n<noindex><a rel=\"nofollow\" href=\"https:\/\/ru.wikipedia.org\/wiki\/TETRA\">TETRA<\/a><\/noindex> (Terrestrial Trunked Radio) \u2014 to je profesionalni sustav korporativne radio veze s dovoljno velikim mogu\u0107nostima (grupni pozivi, \u0161ifriranje, povezivanje vi\u0161e mre\u017ea itd.). Njegovi signali, ako nisu \u0161ifrirani, tako\u0111er se mogu primati pomo\u0107u ra\u010dunala i SDR prijemnika.<\/p>\n<p>TETRA dekoder za Linux postojao je <noindex><a rel=\"nofollow\" href=\"https:\/\/osmocom.org\/projects\/tetra\/wiki\/OsmocomTETRA\">prili\u010dno davno<\/a><\/noindex>, ali njegova konfiguracija bila je daleko od trivijalne, a otprilike prije godinu dana ruski programer stvorio je <noindex><a rel=\"nofollow\" href=\"https:\/\/www.rtl-sdr.com\/sdr-tetra-plugin-now-available-at-rtl-sdr-ru\/\">plugin za prijem TETRA<\/a><\/noindex> za SDR#. Sada se taj zadatak rje\u0161ava gotovo doslovno u dva klika, program omogu\u0107uje prikaz informacija o sustavu, slu\u0161anje glasovnih poruka, prikupljanje statistike i sli\u010dno.<\/p>\n<p><img decoding=\"async\" alt=\"\u0160to se \u010duje na radiju? Primamo i de\u0161ifriramo najzanimljivije signale. Dio 2, FM\" src=\"\/wp-content\/uploads\/2019\/05\/c6ecdd05402b9f420acde1cfd0cec51b.jpg\" style=\"display:block;margin: 0 auto;\" \/><br \/>\n<br \/>\nPlugin ne implementira sve mogu\u0107nosti standarda, ali osnovne funkcije vi\u0161e-manje rade.<\/p>\n<p>Prema Wikipediji, Tetra se mo\u017ee koristiti u hitnoj pomo\u0107i, policiji, na \u017eeljezni\u010dkom prijevozu itd. \u0160to se ti\u010de njene rasprostranjenosti u Rusiji, nisam siguran (izgleda da je Tetra mre\u017ea kori\u0161tena na SP2018, ali to nije potvr\u0111eno), zainteresirani mogu provjeriti sami \u2014 Tetra signali su lako prepoznatljivi i imaju \u0161irinu od 25KHz, kao \u0161to se mo\u017ee vidjeti na snimci ekrana. <\/p>\n<p>Naravno, ako je u mre\u017ei omogu\u0107eno \u0161ifriranje (takva mogu\u0107nost postoji u Tetri), dodatak ne\u0107e raditi \u2014 umjesto govora \u010dut \u0107ete samo \u00abmuhanje\u00bb.<\/p>\n<h2>ADSB<\/h2>\n<p>\nPodi\u0107i \u0107emo se jo\u0161 vi\u0161e po frekvenciji, na frekvenciji od 1.09GHz prenose se signali transpondera zrakoplova, \u0161to omogu\u0107uje web stranicama poput FlightRadar24 da prate letove. Ovaj protokol je ve\u0107 bio obra\u0111en ranije, pa se ne\u0107u ponavljati (\u010dlanak je i ovako prevelik), zainteresirani mogu pro\u010ditati <noindex><a rel=\"nofollow\" href=\"https:\/\/habr.com\/ru\/post\/408003\/\">prvi<\/a><\/noindex> i <noindex><a rel=\"nofollow\" href=\"https:\/\/habr.com\/ru\/post\/443498\/\">drugi<\/a><\/noindex> dio.<\/p>\n<h2>Zaklju\u010dak<\/h2>\n<p>\nKao \u0161to se mo\u017ee vidjeti, \u010dak i s prijemnikom od 30$ mo\u017ee se prona\u0107i mnogo zanimljivih stvari u eteru. Siguran sam da ovdje nije nabrojano sve, a ne\u0161to sam mo\u017eda propustio ili ne znam. Zainteresirani mogu probati sami \u2014 to je dobar na\u010din da se bolje razumije princip rada takvih ili onakvih sustava.<\/p>\n<p>Amatersku radiokomunikaciju nisam razmatrao, iako postoji i na VHF-u, ali \u010dlanak je ipak o slu\u017ebenoj komunikaciji.<\/p>\n<p>P.S.: Posebno za <noindex><a rel=\"nofollow\" href=\"http:\/\/lurkmore.to\/%D0%9A%D1%83%D0%BB%D1%85%D0%B0%D1%86%D0%BA%D0%B5%D1%80\">kulha\u010dke<\/a><\/noindex> mo\u017ee se primijetiti da se u otvorenom eteru ve\u0107 otprilike 50 godina ne prenosi ni\u0161ta stvarno tajno, tako da s 'ovog' stanovi\u0161ta, ne vrijedi tro\u0161iti vrijeme i novac. No, s aspekta prou\u010davanja principa komunikacije i raznih in\u017eenjerskih sustava, upoznavanje s pravim radom pravih mre\u017ea je sasvim zanimljivo i pou\u010dno.<br \/>\n<br \/>Izvor: <a content=\"nofollow\" rel=\"nofollow\" href=\"https:\/\/habr.com\/ru\/post\/450578\/\">habr.com<\/a><\/p>","protected":false,"gt_translate_keys":[{"key":"rendered","format":"html"}]},"excerpt":{"rendered":"<p>\u041f\u0440\u0438\u0432\u0435\u0442, \u0425\u0430\u0431\u0440. \u0412 \u043f\u0435\u0440\u0432\u043e\u0439 \u0447\u0430\u0441\u0442\u0438 \u0431\u044b\u043b\u0438 \u043e\u043f\u0438\u0441\u0430\u043d\u044b \u043d\u0435\u043a\u043e\u0442\u043e\u0440\u044b\u0435 \u0441\u0438\u0433\u043d\u0430\u043b\u044b, \u043a\u043e\u0442\u043e\u0440\u044b\u0435 \u043c\u043e\u0436\u043d\u043e \u043f\u0440\u0438\u043d\u044f\u0442\u044c \u043d\u0430 \u0434\u043b\u0438\u043d\u043d\u044b\u0445 \u0438 \u043a\u043e\u0440\u043e\u0442\u043a\u0438\u0445 \u0432\u043e\u043b\u043d\u0430\u0445. \u041d\u0435 \u043c\u0435\u043d\u0435\u0435 \u0438\u043d\u0442\u0435\u0440\u0435\u0441\u043d\u044b\u043c \u044f\u0432\u043b\u044f\u0435\u0442\u0441\u044f \u0434\u0438\u0430\u043f\u0430\u0437\u043e\u043d \u0423\u041a\u0412, \u043d\u0430 \u043a\u043e\u0442\u043e\u0440\u043e\u043c \u0442\u043e\u0436\u0435 \u043c\u043e\u0436\u043d\u043e \u043d\u0430\u0439\u0442\u0438 \u043a\u043e\u0435-\u0447\u0442\u043e \u0438\u043d\u0442\u0435\u0440\u0435\u0441\u043d\u043e\u0435. \u041a\u0430\u043a \u0438 \u0432 \u043f\u0435\u0440\u0432\u043e\u0439 \u0447\u0430\u0441\u0442\u0438, \u0431\u0443\u0434\u0443\u0442 \u0440\u0430\u0441\u0441\u043c\u043e\u0442\u0440\u0435\u043d\u044b \u0442\u0435 \u0441\u0438\u0433\u043d\u0430\u043b\u044b, \u043a\u043e\u0442\u043e\u0440\u044b\u0435 \u043c\u043e\u0436\u043d\u043e \u0441\u0430\u043c\u043e\u0441\u0442\u043e\u044f\u0442\u0435\u043b\u044c\u043d\u043e \u0434\u0435\u043a\u043e\u0434\u0438\u0440\u043e\u0432\u0430\u0442\u044c \u0441 \u043f\u043e\u043c\u043e\u0449\u044c\u044e \u043a\u043e\u043c\u043f\u044c\u044e\u0442\u0435\u0440\u0430. \u041a\u043e\u043c\u0443 \u0438\u043d\u0442\u0435\u0440\u0435\u0441\u043d\u043e, \u043a\u0430\u043a \u044d\u0442\u043e \u0440\u0430\u0431\u043e\u0442\u0430\u0435\u0442, \u043f\u0440\u043e\u0434\u043e\u043b\u0436\u0435\u043d\u0438\u0435 \u043f\u043e\u0434 \u043a\u0430\u0442\u043e\u043c. \u0412 [&hellip;]<\/p>\n","protected":false,"gt_translate_keys":[{"key":"rendered","format":"html"}]},"author":1,"featured_media":24864,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[688],"tags":[],"class_list":["post-33117","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-administrirovanie"],"aioseo_notices":[],"aioseo_head":"\n\t\t<!-- All in One SEO 5.0.4 - aioseo.com -->\n\t<meta name=\"description\" content=\"\u041f\u0440\u0438\u0432\u0435\u0442, \u0425\u0430\u0431\u0440. \u0412 \u043f\u0435\u0440\u0432\u043e\u0439 \u0447\u0430\u0441\u0442\u0438 \u0431\u044b\u043b\u0438 \u043e\u043f\u0438\u0441\u0430\u043d\u044b \u043d\u0435\u043a\u043e\u0442\u043e\u0440\u044b\u0435 \u0441\u0438\u0433\u043d\u0430\u043b\u044b, \u043a\u043e\u0442\u043e\u0440\u044b\u0435 \u043c\u043e\u0436\u043d\u043e \u043f\u0440\u0438\u043d\u044f\u0442\u044c \u043d\u0430 \u0434\u043b\u0438\u043d\u043d\u044b\u0445 \u0438 \u043a\u043e\u0440\u043e\u0442\u043a\u0438\u0445 \u0432\u043e\u043b\u043d\u0430\u0445.\" \/>\n\t<meta name=\"robots\" content=\"max-image-preview:large\" \/>\n\t<meta name=\"author\" content=\"Yuri Gagarin\"\/>\n\t<link rel=\"canonical\" href=\"https:\/\/prohoster.info\/hr\/blog\/administrirovanie\/chto-slyshno-v-radioefire-prinimaem-i-dekodiruem-naibolee-interesnye-signaly-chast-2-ukv\" \/>\n\t\t<meta name=\"generator\" content=\"All in One SEO (AIOSEO) 5.0.4\" \/>\n\t\t<meta property=\"og:locale\" content=\"hr_HR\" \/>\n\t\t<meta property=\"og:site_name\" content=\"ProHoster | \u041a\u0443\u043f\u0438\u0442\u044c \u043d\u0430\u0434\u0435\u0436\u043d\u044b\u0439 \u0445\u043e\u0441\u0442\u0438\u043d\u0433 \u0434\u043b\u044f \u0441\u0430\u0439\u0442\u043e\u0432 \u0441 \u0437\u0430\u0449\u0438\u0442\u043e\u0439 \u043e\u0442 DDoS, VPS VDS \u0441\u0435\u0440\u0432\u0435\u0440\u044b\" \/>\n\t\t<meta property=\"og:type\" content=\"article\" \/>\n\t\t<meta property=\"og:title\" content=\"\ud83e\udd47\u0427\u0442\u043e \u0441\u043b\u044b\u0448\u043d\u043e \u0432 \u0440\u0430\u0434\u0438\u043e\u044d\u0444\u0438\u0440\u0435? 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